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Analizirali smo vpliv žlindre z nizko bazičnostjo na kemično sestavo in nekovinske vključke v jeklu 46MnVS5 v primerjavi s standardno žlindro. Cilj naloge je bil izboljšati stabilnost procesa legiranja žvepla in povečati njegov izkoristek z uporabo nizko-bazične žlindre. Nizko-bazična žlindra ima primerno nizko sulfidno kapaciteto in izpolnjuje pogoje za nastanek deformabilnih nekovinskih vključkov z nizkim tališčem, hkrati pa ni preveč agresivna do ognjevzdržne obzidave ponovce. Naredili smo kemično analizo vzorcev žlindre in jekla za šarži s standardno in nizko bazično žlindro. Med izdelavo posameznih šarž smo vzorce jekla in žlindre vzeli tik po začetku in tik pred koncem obdelave na ponovčni peči. Vzorec jekla smo vzeli še iz vmesne ponovce med litjem na kontinuirni napravi, odvzeli pa smo tudi vzorec iz valjanca s premerom 95 mm. S podatki meritev smo izračunali sulfidno kapaciteto žlindre, porazdelitveni koeficient žvepla med žlindro in talino ter grafično prikazali spreminjanje vsebnosti žvepla v jekleni talini obeh šarž. Opravili smo tudi avtomatsko analizo vključkov v jeklu in ploskovno EDS analizo značilnih vključkov obeh šarž, ki smo jih primerjali. Ugotovili smo, da ima nizko-bazična žlindra nižjo sulfidno kapaciteto, zaradi česar se v talini ohrani več žvepla kot pri standardnem postopku. Med izdelavo jekla se zato porabi dosti manj žvepla. Prav tako ima slabšo sposobnost odstranjevanja nekovinskih vključkov iz taline, oksidni vključki pa vsebujejo večji delež SiO2 in so bolj preoblikovalni od vključkov v standardni šarži. The influence of low-basicity slag on the chemistry and non-metallic inclusions in 46MnVS5 steel was analysed in comparison to standard ladle slag. The aim was to improve the stability of the process of alloying sulphur and to improve its yield with the use of a low basicity slag. The slag has a low sulphide capacity and is not too aggressive towards the ladle refractory while fulfilling conditions for the formation of deformable non-metallic inclusions with a low liquidus temperature. Slag and steel samples were analysed for the standard and the low-basicity technology. Samples were taken at the beginning and at the end of ladle treatment and while casting. As-rolled samples were also investigated. Sulphide capacity and sulphur distribution ratio were calculated for all slag samples. Automated inclusion analysis and surface EDS inclusion analysis was performed for all steel samples and compared for both technologies. The low-basicity slag has a lower sulphur capacity and thus helps retain sulphur in the steel melt. Steel cleanliness was also worse in the samples with the low-basicity slag. Oxide non-metallic inclusions contained more SiO2 and were more deformable than those in the standard steel samples.

The paper aims to determine the mechanical properties of the adhesive joints made with acrylic pressure-sensitive adhesives. Two types of double-sided acrylic pressure-sensitive adhesive tapes are used. Three construction materials are used to prepare the adhesive joints: structural steel sheet (C45), aluminium alloy sheet (EN-AW 5754), and titanium sheet (Grade 2). Strength tests of adhesive joints made with the pressure-sensitive adhesive tapes are carried out both after conditioning time at room temperature (23 °C) and subjected to thermal shocks (500 cycles: +60 °C / –40 °C). Strength tests are carried out based on the DIN EN 1465 standard on a Zwick/Roell Z150 testing machine. The main conclusion from the tests carried out was the positive effect of thermal shocks on the mechanical strength of joints bonded with pressure-sensitive adhesive tape.

Pravilno in natančno izmerjene temperature so pomemben podatek za izvedbo in načrtovanje procesov na področju proizvodnih in metalurških tehnologij. V pilotnem laboratoriju smo pri procesih temperaturnega utrujanja jekel izvedli meritve temperatur na preizkušancih iz modificiranega jekla AISI H11. Izvedli smo simulacije temperaturnega utrujanja, izmerili temperature kritičnih točk testnega preizkušanca, analizirali rezultate izvedenih meritev ter predlagali ustrezne rešitve. Za testirano jeklo je process napredovanja razpok do 5000-ega cikla počasen, med 5000 in 10000 ciklom se pojavijo večje razpoke, po 10000 ciklu pa se širjenje oziroma napredovanje razpok ponovno upočasni. Correctly and precisely measured temperatures are important information for the implementation and planning of processes in the field of production and metallurgical technologies. In the pilot laboratory, during temperature fatigue processes of steels, we performed temperature measurements on test specimens made of modificated AISI H11 steel. We carried out simulations of temperature fatigue, measured the temperatures of the critical points of the test specimen, analyzed the results of the measurements and proposed appropriate solutions. For the tested steel, the crack propagation process is slow up to the 5000th cycle, between 5000 and 10000 cycles, larger cracks appear, and after 10000 cycle, the propagation or propagation of cracks slows down again.

V okviru diplomskega dela so bile obravnavane metode in orodja vrednotenja in analize življenjskega cikla proizvodov. Podrobneje sta predstavljeni SWOT analiza in LCA metoda vrednotenja in ocene življenjskega cikla proizvodov, procesov in storitev. Na kratko je predstavljen standard za upravljanja z okoljem ISO 14001, ter standardi družine ISO 14040: Splošna načela za vodenje in vrednotenje študije LCA. Izvedena je uporaba obeh metod in orodij na področju proizvodnih tehnologij s posebnim poudarkom na področju proizvodnje jekla in jeklenih polproizvodov. V okviru dela je izvedena tudi kompleksna analiza in vrednotenje življenjskega cikla ter SWOT analiza izbranega jeklenega proizvoda in sicer je bila izvedena analiza za primer visoko kakovostnega visoko trdnega obrabno obstojnega jekla. Jeklo je proizvedeno s strani največjega proizvajalca jekla v Sloveniji in je zaradi zaščite podatkov in interesov vseh vključenih deležnikov v nadaljevanju imenovano kot »testno jeklo« oziroma na kratko TVTJ. Delo je doprinos k varstvu okolja in zmanjšanju porabe energije in surovin ter prispevek k dvigu kakovosti in produktivnosti. In this thesis, we reviewed various tools and methods used for assessment and analysis of the life cycle of certain products. We provided a more detailed overview of SWOT analysis and the LCA method for reviewing and evaluating the life cycles of products, processes and utilities. Herein we also reviewed the ISO 14001 standard for conduct as it relates to the environment, as well as the ISO 14040 family of standards, which encompass the general guidelines for management and assessment of LCA studies. We then employed both SWOT analysis and the LCA method in the field of production technology, with emphasis on the production of steel and its intermediate products. As a part of this thesis, we also performed a complex analysis and life cycle assessment, as well as SWOT analysis, of a selected steel product, more specifically solid, wear-resistant steel, which we acquired from the largest Slovenian steel manufacturer. In this work, the product is referred to either as "test steel" or with the acronym TVTJ in the interest of data protection. This thesis is a contribution to environmental conservation efforts, as well as reduction of energy and raw material consumption and an increase in quality and productivity as it relates to the Slovenian steel industry.

V magistrskem delu so predstavljene spremembe pri potresnoodpornem projektiranju konstrukcij, ki jih uvaja predlog novega standarda Evrokod 8. Novosti smo analizirali na praktičnem primeru 5-etažnega jeklenega objekta iz momentih okvirov in okvirov z ekscentričnimi povezji. Preučili smo nove definicije razredov duktilnosti, faktorjev obnašanja, faktorja občutljivosti za stavbe in kontrolo vplivov teorije drugega reda, kontrole etažnih pomikov v novih mejnih stanjih ter pravila za projektiranje jeklenih konstrukcij. Pravila iz trenutnega standarda Evrokod 8 za razred duktilnosti DCH smo primerjali s predlaganimi pravili za nova razreda duktilnosti DC2 in DC3. Potresnoodporno analizo smo izvedli za ravninske modele momentnih okvirov in okvirov z ekscentričnimi povezji z metodo z vodoravnimi silami. Za momente okvire smo izvedli tudi poenostavljeno nelinearno statično analizo. Ugotovili smo, da projektiranje momentnih okvirov po predlogu novega standarda Evrokod 8 dovoljuje nekoliko lažje in vitkejše konstrukcije z manjšimi dimenzijami elementov. Pri tem za dimenzioniranje niso več merodajni vplivi teorije drugega reda, temveč omejitve etažnih pomikov. Nasprotno, upoštevanje pravil predloga novega standarda Evrokod 8 povečuje zahteve nosilnosti in stabilnosti elementov ekscentričnega povezja. Sam postopek projektiranja ekscentričnega povezja se ne razlikuje od obstoječega. Zahteve poostruje povečanje potresnega dela obtežbe potresnega projektnega stanja. Obremenitve elementov ekscentričnih povezij v DC3 in DC2 so bile večje do te mere, da je bilo najbolj smiselno povečati število povezij in ohraniti primerljive dimenzije elementov. The master thesis deals with the changes in the seismic resistance design of structures introduced by the proposal of the new standard Eurocode 8. The novelties were analysed on a practical example of a 5-storey steel building stabilised with moment resisting frames and frames with eccentric bracings. The new definitions of ductility classes, behaviour factors, the interstorey drift sensitivity coefficient and the control of second order effects, the limitations of interstorey drifts in the new limit states and the specific rules for steel buildings were examined. The code requirements from the current Eurocode 8 for ductility class DCH were compared to the proposed rules for the new ductility classes DC2 and DC3. Seismic analysis was performed for planar models of moment resisting frames and frames with eccentric bracings using the lateral force method. A nonlinear static analysis (pushover) for the moment resisting frames was also performed. It was found that the design of moment resisting frames according to the proposal of the new Eurocode 8 allows somewhat lighter and slimmer structures. In this case, the influences of the second order effects are no longer governing, but rather by the limitations of interstorey drifts. On the contrary, following the changes of the new Eurocode 8 means higher resistance and stability requirements for frames with eccentric bracings. Seismic resistance design of frames with eccentric bracings does not differ from current process. The resistance and stability requirements are intensified by the increase of the seismic part of the seismic design state. The internal forces in the frame with eccentric bracings designed for DC2 and DC3 were greater to the point that it was more reasonable to increase the number of eccentric bracings and maintain comparable element dimensions.

Preiskovali smo vpliv sestave nekovinskih vključkov na obdelovalnost jekla 20MnVS6 s povečano obdelovalnostjo. Na vzorcih valjancev sedmih industrijskih šarž preiskovanega jekla smo določili obdelovalnost po metodi V15, izvedli avtomatsko analizo nekovinskih vključkov s SEM-om, opremljenim z EDS-modulom, analizo vsebnosti vključkov pod SEM-om, metalografsko analizo pod optičnim mikroskopom, meritve trdote na različnih mestih po preseku valjanca in EDS ploskovno analizo karakterističnih nekovinskih vključkov. Pri istih sedmih šaržah smo ob koncu obdelave na ponovčni peči odvzeli vzorec taline z napravo za odvzem vzorcev TOS, na katerih smo izmerili vsebnost skupnega kisika. Odvzeli smo tudi vzorce taline iz vmesne ponovce na napravi za kontinuirno litje jekla po t. i. metodi lizike, na katerih smo izvedli avtomatsko analizo nekovinskih vključkov. Ugotovili smo, da količina zaznanih vključkov pod SEM-om v vzorcih valjancev raste z meritvijo skupnega kisika v vzorcih taline, odvzetih ob koncu obdelave jekla na ponovčni peči. Indeks obdelovalnosti V15 pada z naraščanjem deleža CaS v vključkih iz vzorca valjanca in lizike, kar smo pripisali reakciji kalcija iz kalcijevega aluminata z žveplom iz taline in posledičnega osiromašenja notranjosti vključka s kalcijem med strjevanjem. Indeks obdelovalnosti V15 raste z meritvijo skupnega kisika v vzorcih taline, odvzetih ob koncu obdelave jekla na ponovčni peči. Delež CaS v vključkih iz valjancev in lizik pada z naraščanjem vsebnosti skupnega kisika. The influence of non-metallic inclusions on the machinability of 20MnVS6 steel was investigated. As-rolled samples of seven industrial batches of steel were tested for machinability with the V15 test. Automatic inclusion analysis with an EDS-equipped scanning electron microscope, determination inclusion content with SEM, metallographic analysis with an optical microscope, hardness testing and EDS analysis of characteristic inclusions was performed. Total oxygen samples were taken after secondary refining of steel in the ladle furnace. Automatic analysis of tundish lollipop samples was performed. It was determined that inclusion content in as-rolled samples correlates well with total oxygen content in melt samples from the ladle furnace. Machinability index V15 decreases with an increase in CaS content in inclusions in as rolled and lollipop samples. This was attributed to a reaction of calcium from the modified calcium-aluminate inclusions with sulfur from the steel melt during solidification. Machinability index V15 increases with total oxygen content in melt samples from the ladle furnace. CaS content in as-rolled and lollipop samples decreases with increasing total oxygen content in ladle furnace samples.

Alpinizem je veda o Alpah in alpinistiki. Je vzpenjanje na visoke vrhove po nezavarovanih in nezaznamovanih smereh. Ta šport je sprožil več kulturnih odzivov, izraženih v literaturi, slikarstvu, fotografiji, filmu itd. Mnogi strokovnjaki štejejo alpinizem med najzahtevnejše športe, tako po fizični kot psihični plati. Nasprotniki alpinistu so gore, stene, grebeni in ledni slapovi. Osnovna vrednota tega športa je v človeku samem. Intenzivnost doživljanja v gorstvih, tovarištvo v navezi, sožitje z naravo, estetika, romantika, samopotrditev. Da je osvajanje najzahtevnejših vrhov čimbolj varno, mora biti vsak alpinist seznanjen z plezalno in vrvno tehniko. V svojem diplomskem delu sem predstavila alpinistično opremo in njen razvoj vzporedno s samim športom. Osredotočila sem se na alpinistične kline. Moja raziskava se je začela s povpraševanjem in iskanjem starih izbitih klinov. Nabrala sem jih kar nekaj iz Centralnih Alp, nekateri izmed njih imajo arheološko vrednost. Za raziskave pa smo izbrali alpinistične kline jeseničane. Slovenski alpinistični odsek Jesenice ima namreč tradicijo izdelovanja klinov že skoraj 50 let. Poudarek smo namenili metalografski analizi alpinističnih klinov. S svetlobnim in vrstičnim elektronskim mikroskopom (SEM) smo napravili karakterizacijo mikrostrukture v posameznih klinih, osredotočili smo se tudi na nekovinske vključke in ocenili njihovo sestavo, obliko in velikost. Kemijsko sestavo posameznih vključkov smo izmerili po metodi energijske disperzijske spektroskopije rentgenskih žarkov (EDS). Po metodah optične emisijske spektroskopije (OES) in z metodo infrardeče absorpcije po sežigu v indukcijski peči pa smo določili kemijsko sestavo vzorčnih klinov. Izmerili smo tudi njihovo trdoto po metodi Rockwell. Mountaineering or alpinism is the set of outdoor activities that involves ascending tall mountains. Alpinism is considered as science of Alps. This sport has triggered many cultural responses expressed in literature, painting, photography, film and so on. Many experts consider alpinism one of the most demanding sports, physically and mentally. The obstacles of an alpine climber are mountain ranges, walls, ridges and ice waterfalls. The basic value of the sport it is hold in a man himself. Intensity of experience, camaraderie with climbing partner, coexistence with nature, aesthetics, romance, self-affirmation. In the classic period of mountaineering free ascent meant ascending high peaks without technical equipment. Now this has changed, modern alpinism aims to conquer most demanding peaks with technical equipment. In my dissertation, I presented mountaineering equipment and it’s development in parallel with the sport itself. I focused mainly on climbing pitons. My research began with enquiry and demand to get old and rusty pitons. I have collected quite a few of them from Central Alps. Some of them have archaeological value. For our research we chose Slovenian climbing pitons named Jeseničani. Slovenian alpine club Jesenice has a tradition of making climbing pitons for nearly fifty years. We focused on the metallographic research of climbing piton. We have characterised microstructure by light and scanning electron microscopy (SEM), we also focused on non-metallic inclusions. We evaluated their composition, size and shape. Chemical composition was measured by X-ray spectroscopy (EDS). The chemical composition of pitons was determinated by optical emission spectroscopy (OES) and by infrared absorption after combustion in an induction furnace. We also measured hardness using the method Rockwell.

Namen magistrske naloge je določitev lomne in udarne žilavosti sive litine s kroglastim grafitom kvalitete EN-GJS-400-18LT pri različnih temperaturah ter primerjava z valjanim konstrukcijskim jeklom S235JR+AR. Ulitih je bilo več t. i. Y-prob iz sive litine, iz katerih smo izdelali preizkušance za preizkus lomne in udarne žilavosti ter vzorce za določitev mikrostrukturnih lastnosti. Iz vroče valjane jeklene plošče, debeline 25 mm smo prav tako izdelali preizkušance za preizkus lomne in udarne žilavosti ter vzorce za analizo mikrostrukture. Kemijsko sestavo smo določili s pomočjo optične emisijske spektroskopije, karakterizacija mikrostrukture je potekala s pomočjo svetlobne mikroskopije in programa Analysis 5.0. Določili smo udarno žilavost obeh materialov po Charpyu pri sobni temperaturi, 0 °C, -20 °C in -40 °C. Pri enakih temperaturah smo določili še kritične vrednosti J-integrala, odpiranje vrha razpoke oziroma CTOD (crack tip opening displacement) ter lomno žilavost z uporabo tri-točkovnega upogibnega preizkusa. Mikrofraktografija je bila narejena z vrstičnim elektronskim mikroskopom. Mikrostruktura litine EN-GJS-400-18LT je sestavljena iz feritno-perlitne matrice in ogljika, strjenega v obliki grafitnih krogel. Mikrostruktura valjanega jekla S235JR+AR je feritno-perlitna, pri čemer lahko opazimo, da so kristalna zrna nekoliko podolgovata in usmerjena v smeri valjanja. Izkazalo se je, da je udarna žilavost jekla pri sobni temperaturi bistveno večja kot udarna žilavost sive litine, a z nižanjem temperature drastično pade in se pri -40 °C celo izenači z udarno žilavostjo sive litine. Lomna žilavost sive litine je pri vseh temperaturah večja od lomne žilavosti jekla in s padcem temperature celo nekoliko naraste. The purpose of this master thesis is to determine the fracture and impact toughness of EN-GJS-400-18LT ductile iron at different temperatures and compare it to S235JR+AR hot-rolled structural steel. Several Y-block ductile iron castings were made in order to make specimens for determining the fracture and impact toughness and samples for metallographic examination. We made specimens for impact and fracture toughness as well as metallographic samples out of 25 mm thick hot rolled steel plate. Microstructure examination was performed by light microscopy, while chemical analysis was performed by optical emission spectroscopy. Impact toughness was determined with the use of the Charpy method at room temperature, 0 °C, -20 °C and -40°C. At the same temperatures, J-integral values as well as crack tip opening displacement – CTOD and fracture toughness were determined by three-point bending test. Microfractography was performed by using scanning electron microscope. EN-GJS-400-18LT has a ferritic – perlitic microstructure with carbon in form of graphite nodules embedded in the matrix. Hot rolled S235JR+AR steel has a ferritic – perlitic microstructure with crystal grains extended and orientated in the direction of rolling. It turned out that the impact toughness of steel at room temperature is greatly higher than that of ductile iron, but it decreases sharply with decreasing temperature. At -40 °C the impact toughness of both materials is practically the same. Fracture toughness of ductile iron is higher at all temperatures tested than fracture toughness of steel and it actually rises a bit with decreasing temperature.

How the contact behaviours of steel engineering surfaces with different roughnesses (R$_a$ = 0.1, 0.6 and 1.0 µm) are affected by the asperity work-hardening and the deformation regime are described here. Large values of the plasticity index Ψ between 20 and 50 indicate that all the surfaces should undergo a full plastic deformation. However, in the loading range up to the yield stress (on a nominal contact area) the rough surfaces exhibited at least 10 % elastic deformation, while for the smooth surfaces the elastic deformation was as much as 44 %. During the loading, the work-hardening increased the hardness of the rough surfaces by up to 63 %, and that of the smooth surfaces by up to 20 %. However, the asperities were able to carry the load that resulted in as much as a 4–10-times-higher contact pressure than the (initial) bulk yield strength. The proposed contact mechanisms for such an increased asperity-load-carrying capacity depend on the surface roughness. For the rough surfaces this is due to the work-hardening, while for the smooth surfaces the dominant mechanisms enhancing the load-carrying capacity are the work-hardening combined with the hydrostatic bulk stresses.

The effect of deep cryogenic treatment (DCT) on corrosion resistance of steels AISI 52100 and AISI D3 is investigated and compared with conventional heat-treated counterparts. DCTʼs influence on microstructural changes is subsequently correlated to the corrosion resistance. DCT is confirmed to reduce the formation of corrosion products on steelsʼ surface, retard the corrosion products development and propagation. DCT reduces surface cracking, which is considered to be related to modified residual stress state of the material. DCTʼs influence on each steel results from the altered microstructure and alloying element concentration that depends on steel matrix and type. This study presents DCT as an effective method for corrosion resistance alteration of steels. Nasl. z nasl. zaslona. Opis vira z dne 26. 10. 2021. Št. članka 6357. Bibliografija: str. 15-16. Abstract.

V tem delu smo raziskovali vpliv razmerja med drsenjem in kotaljenjem (SRR) na koeficient trenja. Obravnavali smo mazan kontakt med polimerno kroglico in jeklenim diskom. Za testiranje smo uporabili napravo Mini Traction Machine, ki je omogočala nastavitev poljubnih SRR in celo spreminjanje SRR tekom testa. Tako smo ves čas testa ohranjali ostale pogoje v kontaktu nespremenjene. Meritve testov smo numerično obdelali in rezultate predstavili v obliki diagramov. Ti so pokazali, da se v večini obratovalnih pogojev koeficient trenja povečuje, če povečujemo |SRR|. Izjema so bili testi, izvedenih pri nižji obremenitvi in negativnih vrednostih SRR. Pri njih se je koeficient trenja pri povečevanju |SRR| zmanjševal. Kontakt med polimerom in jeklom je izkazoval nižji koeficient trenja pri višji obremenitvi v primerjavi s testi opravljenimi pri nižji obremenitvi. Na podlagi tega predvidevamo, da se na jekleni površini tvori več polimernega filma pri višji obremenitvi, kakor pri nižji. In this paper, the effect of slide-to-roll ratio (SRR) on coefficient of friction was investigated. Measurements were taken from a lubricated contact between a polymer ball and steel disc. The experiments were carried out on Mini Traction Machine, which allowed setting of any SRR and also managed to change SRR during tests. That way, all other parameters in the contact remained unchanged for full duration of tests. Raw data, measured in experiments was then numerically processed in order to present them in the form of graphs. Graphs showed that in most running conditions bigger |SRR| value resulted in higher coefficient of friction. However, there was one exception. When the contact was tested at lower load and at negative SRR values, growing of |SRR| reduced coefficient of friction. Additionally, the contact between polymer and steel showed lower coefficient of friction at higher load, compared to tests performed at lower load. These phenomena might indicate that there is increased formation of polymer transfer film on steel counterpart under higher load.

Effect of lateral actions evolving from restrained thermal expansions of horizontal structural elements (beams, slabs) on stability of vertical elements (columns, walls) of fire-engulfed buildings remains unaddressed some-times in engineering practice. Discussion with engineers has revealed that two reasons may contribute most to such design inconsistency. The first is premature assumptions that the effects of these actions can not be suffi-cient to exceed the effects of other lateral design actions, especially if for the same building considerable seismic influences are also expected. The second reason is the fact that, according to the present version of Eurocodes, these actions need not be addressed specifically if the design is carried out under standard fire curve. This curve, however, is still applied often in practice. For certain vertical members, such as the ones positioned somewhere within the middle of fire compartments, indirect lateral fire actions may indeed be negligible, e.g., due to partial or complete balancation of these actions in fire evolving simultaneously at two opposite sides. However, more pronounced effect might be observed for vertical members at the boundary between a fire-engulfed and a neighbouring cold-side compartment, especially in steel or RC buildings with larger horizontal spans prone to striking lateral thermal elongations. While such structures represent a fair share of existing building stock (they are common, e.g., in prefabricated industrial and commercial buildings), this problem deserves a special attention. In this paper two real one-storey large-span halls are analysed for confirmation of the above hy-pothesis. Each of them comprises two structurally connected units, i.e. one RC- and the other steel-framed, where fire is assumed to engulf the steel-framed unit. Stability of the cold-side RC columns at the boundary between both sectors is discussed and for the latter indirect fire actions from the connecting fire-engulfed steel members are found to be of a comparable or a greater size to effect of moderate-size seismic actions. The greatest effects of the observed fire actions are found at average steel temperatures below 400 C. This is a rather low temperature expected to be achieved (sooner or later) in most fire-affected steel elements with or without fire protection. At the same time, as in this paper also proven by results of exact visco-plastic structural computations, this is also a temperature at which no pronounced creep strains yet evolve in steel within time frames relevant for common structural fire analyses. In addition, the paper also shows that these conclusions would not change for other variations of the discussed two buildings where other possible kinematic boundary conditions were applied at the ends of the steel members or other possible thermal boundary conditions were assumed along their longitudinal surfaces. At most, the observed indirect fire effects would only increase further in these cases. Thus, at least for structures of a similar type (i.e. one-storey frame structures of horizontal spans of similar size and materials), the authors propose that the discussed lateral indirect fire actions are not dismissed from any design procedure regardless of the expected fire scenario as long as steel is allowed to heat to moderate temperatures (around 400 C). In the last part of the paper the authors also discuss possible change of these findings for multi-storey frame structures and/or frame structures of other spans. However, for these (and other possible) structural types, a more detailed further investigation is proposed.

The purpose of the present paper is to predict the grain size of steel during the hot-rolling process. The basis represents a macroscopic simulation system that can cope with temperatures, stresses and strains of steel in a complete continuous rolling mill, including reversible pre-rolling and finishing rolling with several tenths of rolling passes. The grain size models, newly introduced in the present paper, are one-way coupled to the macro-scale calculations performed with the slice model assumption. Macroscale solution is based on a novel radial basis function collocation method. This numerical method is truly meshless by involving the space discretization in arbitrarily distributed nodes without meshing. A new efficient node generation algorithm is implemented in the present paper and demonstrated for irregular domains of the slice as they appear in different rolling passes. Multiple grain size prediction models are considered. Grain size prediction models are based on empirical relations. Austenite grain size at each rolling pass as well as the ferrite grain size at the end of rolling are predicted in this simulation. It is also shown that based on the rolling schedule, it is highly likely that recrystallization takes place at each pass throughout a continuous rolling mill. The simulation system is coded as a user-friendly computer application for industrial use based on programming language C# and an open source developer platform NET and runs on regular personal computers the computational time for a typical rolling simulation is usually less than one hour and can thus be straightforwardly used to optimize the rolling mill design in a reasonable time.

The present study focuses on improving the ultimate tensile strength of friction stir welded carbon steel (AISI 1018). The effect of the process parameters (welding speed, tool RPM, and shoulder diameter) on the response parameters (ultimate tensile strength, percentage elongation and percentage reduction in area) were studied. Response surface methodology was used to develop the mathematical model for response parameters, and the adequacy of the model was checked using analysis of variance (ANOVA). The welding speed and tool RPM were found to affect the ultimate tensile strength significantly. The percentage elongation was affected only by welding speed. The percentage reduction in the area was affected by welding speed and shoulder diameter. The microstructure and microhardness of the weld have been studied and reported in the study.

Odnos med konjem in človekom je že od nekdaj vzajemen. O tem pričajo najdbe vse od rimskih konjskih sandalov, predhodnikov današnjih konjskih podkev, do prvih primerkov podkev, primerljivih oblik z današnjimi. O tem pričajo tudi preiskave katere smo izvedli v okviru tega diplomskega dela. Konjske podkve različnih proizvajalcev, iz različnih zlitin, vključno z eno starinsko podkvijo, katere izvor smo ocenili v 15. stoletje, smo preiskali s sodobnimi metalurškimi metodami. Zanimale so nas dimenzije in mase podkev, poudarek pa smo namenili kemijskim analizam zlitin, iz katerih so bile narejene podkve ter nekovinskih vključkov katere smo v podkvah našli. Mikrostrukture podkev smo si ogledali z vrstičnim elektronskim mikroskopom (SEM), kemijsko sestavo posameznih faz pa izmerili po metodi energijske disperzijske spektroskopije rentgenskih žarkov (EDS). Kemijske sestave zlitin smo izmerili z metodami optične emisijske spektroskopije (OES), z metodo infrardeče absorpcije po sežigu v indukcijski peči in pa z rentgensko fluorescenčno spektroskopijo (XRF). Izmerili smo tudi trdote vzorčnih podkev kot tudi analizirali njihove mikrostrukture. Trdote smo merili z metodama meritve po Vickersu in po Brinellu, mikrostrukture pa smo si ogledali pod svetlobnim mikroskopom. Ugotovili smo, da se proizvajalci podkev v večini držijo obljubljenega in dostavijo to kar konj in kovač potrebujeta, pa najsibo potreba še tako specifična. Ob primerjavi rezultatov preiskav modernih podkev s starinsko, smo potrdili domnevo o razvoju podkev skozi čas. Ugotovili smo, da so se oblika in sestavni deli podkev resnično ohranili od njihove uveljavitve do danes, materiali uporabljeni za njihovo izdelavo pa so doživeli primeren razvoj. The relationship between a horse and a farrier has forever been mutually beneficial. Witnesses to that are archaeological finds from the Roman hipposandals, the predecessors of modern horseshoes, to the first findings of horseshoes of similar shapes as today. Another witness to that is the research carried out in this diploma work. Horseshoes of different manufacturers, made from different alloys, including an old horseshoe, dated into the 15th century, were all investigated with modern metallurgical methods. Our interest laid in the dimensions and masses of horseshoes, with an emphasis on the chemical compositions of alloys, of which the horseshoes were made and chemical compositions of non-metallic inclusions and intermetallic phases, found in those horseshoes. We found the inclusions with the help of a scanning electron microscope (SEM) and measured their chemical compositions with the method of energy-dispersive X-ray spectroscopy (EDS). The chemical compositions of alloys were measured by following methods: optical emission spectroscopy (OES), method of infrared absorption after combustion and by X-ray fluorescence spectroscopy (XRF). We measured the hardnesses of our sample horseshoes and analyzed their microstructures. The hardnesses were measured by the Vickers and by the Brinell hardness tests, and the microstructures were viewed under the light microscope. We came to a conclusion that most of the manufacturers indeed keep their promises and deliver what a horse and a farrier need, whether it be the most specific need. By comparing the results of modern horseshoes with the old horseshoe, we confirmed our assumption of the progress of horseshoes through time. We found out that the shapes and parts of horseshoes didn't change much from their origins until today, but the materials used to make them developed appropriately.

Namen diplomske naloge je iz rezultatov enostopenjskih tlačnih preizkusov izrisati krivulje tečenja in primerjati napetosti, ki smo jih izračunali iz tlačnih preizkusov, z napetostmi, izračunanimi iz sil in dolžin preoblikovalne cone iz realnega procesa plastične predelave na valjalnem stroju za valjanje debele pločevine. Cilj je tudi primerjati napovedane, sile po Simsu, z izmerjenimi silami na samem ogrodju z uporabo temperaturnega modela valjanca. V teoretičnem delu je opisano preiskovano jeklo S960QL poleg splošnega opisa visokotrdnostnih malo-legiranih jekel in njihovih značilnih lastnosti s poudarkom na plastični predelavi (vroče valjanje) z vsemi potrebnimi pripadajočimi enačbami. V okviru eksperimentalnega dela smo na simulatorju termomehanskih metalurških stanj Gleeble 1500D izvedli enostopenjske tlačne preizkuse v vročem ter dobljene surove podatke obdelali in izrisali krivulje tečenja. Iz krivulj tečenja smo določili koeficiente za modelsko napoved sil po Hansel-Spittelovi enačbi, za kar pa smo morali narediti tudi enostaven temperaturni model valjanca za napoved povprečne temperature preoblikovanca ob danem času valjanja in dodatno oceniti ohlajevalno krivuljo z uporabo krivulj tečenja ob znani povprečni napetosti doseženi na ogrodju. Naredili smo tudi primerjavo izračunanih ter ocenjenih temperatur s pomočjo krivulj tečenja z izmerjenimi (s pirometrom) iz realnega procesa vročega valjanja. Za primerjavo povprečnih napetosti smo izvedli modelsko napoved po Simsu za specifičen realen proces z uporabo temperaturnega modela valjanca in potrdili izjemen pomen pravilno ovrednotenih temperatur za dobro ujemanje med napovedjo in industrijskim testom. Zaradi relativno blagih redukcij v delu grobega valjanja se izkaže, da je najboljše ujemanje med napovedanimi in izmerjenimi sila v primeru odčitavanja temperatur iz krivulj tečenja, preko znanih vrednosti logaritemske deformacije in povprečne napetosti (dobljeno iz valjalnega stroja). V primeru večjih redukcij na posamezen prevlek pa pričakujemo boljše ujemanje izmerjenih in napovedanih sil z uporabo modelske napovedi temperatur na račun povečanja globine penetracije deformacije in zajem področja z višjimi temperaturami, kot je podhlajena površina. The aim of this diploma thesis is to plot the stress-strain curves (flow curves) from the results of single-stage pressure tests and compare the values of calculated stress from flow curves with resulting values of the stress obtained from the calculation of forces and other rolling data from the real process of plastic deformation on the heavy plate rolling mill. The aim is also to compare the predicted forces according to Sims with the measured forces on the framework, using pre-made temperature model. In the theoretical part we described the examinated steel S960QL, beside that we also described typical characteristics of HSLA steels in general and the process of plastic deformation (hot rolling) with all the required equations. As a part of experimental work, we performed single-stage pressure tests on thermo-mechanical simulator Gleeble 1500D and then used raw final results to plot the stress-strain curves. From the curves we determined coefficients for the Hansel-Spittel model force forecast, for which we had to make a simple rolling temperature model to forecast the average temperature of the rolled plate at given rolling time and estimate the cooling curve using the flow curves. We also compared calculated and estimated temperatures from flow curves, with measured temperatures (with pyrometer) from the real hot rolling process. For comparison of stress we performed a Sims model forecast for a specific real process, using the rolling temperature model and we confirmed the exceptional importance of correctly evaluated temperatures for a good match between the forecast and the industrial test. Due to the relatively mild reductions in the part of the rough rolling (»roughing«), the best match between the predicted and measured forces is in the case of reading the temperatures from the flow curves, using known values of logaritmic stress and average strain (obtained from the rolling mill). On the other hand in the case of major reductions per coating, we expect a better matching of measured and predicted forces using temperature model, due to increase in depth of penetration of deformation and capture of areas with higher temperatures than the undercooled surface.

V diplomskem delu so prikazani zasnova, statični izračun in dimenzioniranje jeklene konstrukcije medetažnega poslovnega objekta tlorisnih dimenzij 15,0 x 30,0 m in višine 9,50 m. Jeklena konstrukcija objekta je izdelana iz jekla S355, točkovni temelj pa iz armiranega betona C20/25. Obtežba na objekta je izračunana v skladu z evrokodom 1, izračun statike je izdelan s programom SAP2000, dimenzioniranje pa je izvršeno skladno z evrokodom 3. Na koncu so prikazani izračuni nekaj konstrukcijskih detajlov, izračun teže in izdelavnih stroškov jeklene konstrukcije. The diploma thesis presents data, static calculation in dimensions of steel structures of an interfloor office building with floor dimensions of 15.0 x 30.0 m in height of 9.50 m. The steel structure of the building is made of steel S355, the point foundation plate is made of reinforced concrete C20/25. Observation of the devices is calculated in accordance with Eurocode 1, the statics are calculated using SAP2000, and the dimensioning is performed in accordance with Eurocode 3. Finally, they are shown calculations of some structural details, calculation of costs in steel structures.

Cilj raziskave je bil ugotoviti primernost izbranih poliuretanskih in epoksidnih lepil za konstrukcijsko lepljenje lesa in jekla. Preizkusili smo štiri poliuretanska lepila COSMO in dve epoksidni lepili ERGO in XEPOX. Kakovost lepilnega spoja smo ovrednotili s testom strižne trdnosti, ki je sledil posameznim postopkom izpostavitve preizkušancev: izpostavitev standardni klimi, z relativno zračno vlažnostjo 65 % in temperaturo 20 °C; izpostavitev vlažni klimi s 87 % vlažnostjo in temperaturo 20 °C; ter različne izpostavitve (namakanje/kuhanje) v vodi. Rezultati so pokazali, da proučevana poliuretanska lepila z vidika kakovosti lepljenja ne morejo konkurirati epoksidnim lepilom. Proučevani epoksidni lepili sta zagotovili odlično kakovost lepljenja v suhih pogojih ter se izkazali kot pogojno primerni za nekonstrukcijsko rabo v vlažnih pogojih. Za uporabo izbranega lepila v konstrukcijskih aplikacijah je bilo izdano priporočilo, da je potrebno lepilni spoj dodatno ojačati z vijaki, ki bi zagotovili zanesljivost spoja v primeru nastopa izjemne vlage ali požara.

The time for which each contacting body is exposed to a tribological contact affects its interface temperature, third-body and tribofilm formation, and, as a result, the overall tribological behaviour, which may be particularly relevant with very dissimilar material pairs. This work focuses on the tribological properties of unreinforced polyamide (PA6) in self-mated contacts or against steel (SS) as a stationary (SS/PA6) or a moving contact (PA6/SS) body under dry-sliding conditions. Moreover, the effects of the contact pressure and the sliding velocity were investigated for these contacts. In addition, the contact conditions were carefully controlled with measurements of the specimen's surface temperature using an infrared camera. The results show that the tribological behaviour indeed depends significantly on the contact configuration. The tribological properties of the stationary steel pin sliding against a rotating polymer disc (SS/PA6), as well as of a self-mated PA6/PA6 contact, depended substantially on the contact conditions used. In contrast, the contact configuration of a stationary PA6 pin sliding against a rotating steel disc (PA6/SS) showed only a negligible effect on changes in the sliding speed and the load. Moreover, this was clearly the best-performing contact in the study and the beneficial effect is explained by the ability of a rotating disc to remove the heat from the contact zone and, consequently, to lower the temperatures generated in the tribological contact.

V diplomskem delu so opisane splošne lastnosti jekel, toplotne obdelave – poboljšanja in osnove trdote. Delo temelji na preizkušanju in vrednotenju kaljivosti štirih jekel: C10, C15, C60 in 16MnCr5. Dotaknili smo se vpliva ogljika in drugih legirnih elementov na kaljivost ter jih z empirično dobljenimi podatki tudi prikazali. Kaljivost je vrednotena po Jominyjevem in Grossmanovem preizkusu prekaljivosti. Prikazana sta vpliv popuščanja na trdoto ter tudi nastala mikrostruktura pred in po popuščanju v povezavi s trdoto. Posamezne materiale smo med seboj primerjali. Ugotovili smo, da se maksimalna nastala trdota viša sorazmerno z vsebnostjo ogljika, globina prekaljivosti pa z deležem drugih legirnih elementov. This thesis describes the general properties of steels, heat treatment – quenching and tempering, as does basics of harness. Thesis is based on testing and evaluating the hardness of four steels: C10, C15, C60 and 16MnCr5. We discussed the influence of carbon and other alloying elements based on hardenability and displayed them with empirically obtained data. Hardenability is evaluated with Jominy test as with Grossman hardenability test and the effect of tempering on hardness is shown. Obtained microstructure before and after tempering in relation to hardness is also displayed. We then compared individual materials. We considered that the maximum hardness produced increases in proportion to carbon content and the depth of hardenability increases with proportion of other alloying elements.

V diplomskem delu so predstavljeni izsledki raziskave, v kateri je bil z gravimetrično metodo proučevan vpliv različnih vrst zelenega inhibitorja (kostanjev, cvetlični in akacijev med) na hitrost korozijskih procesov. Poskus je bil izveden na jeklu 1.4301, ki sodi med najpogosteje uporabljena nerjavna jekla, v 17,0 % klorovodikovi kislini (HCl). Raziskava obsega inhibicijski vpliv prej omenjenih vrst medu različnih koncentracij (0,5, 1,0, 1,5 in 2,0 %) ter odvisnost korozijskih procesov od dolžine časovnega intervala izpostavitve. Način priprave je bil za vse vzorce enak. Po opravljenih meritvah je sledila analiza rezultatov. Ta je vključevala izračune na osnovi empirično določenih gravimetričnih podatkov (spremembe mas vzorcev) ter računsko določene vrednosti inhibicijske učinkovitosti in korozijske hitrosti. Opravili smo tudi mikroskopsko analizo površine vzorcev ter izvedli meritve z uporabo spektroskopske metode – infrardeča spektroskopija (FTIR). Na podlagi eksperimentalnega dela je moč zaključiti, da med deluje kot učinkovit zelen inhibitor pri izpostavitvi jekla korozivnemu mediju (17,0 % HCl). Pri različnih vrstah medu je trend učinkovitosti podoben. Že v 0,5 % raztopini medu je bila stopnja inhibicije več kot 50 %, v 2,0 % raztopini medu pa se je vrednost tipično povečala nad 85 %. Pri večini meritev je bila najvišja vrednost inhibicijske učinkovitosti pri določeni koncentraciji medu dosežena pri 8 urni izpostavitvi. In this BS thesis are presented the results of a study, with the main focus was: how different types of green inhibitors (chestnut, flower and acacia honey) influence the speed of corrosion processes, all studied with the gravimetrically method. The experiment was performed on 1.4301 steel, which is one of the most commonly used stainless steels, in 17.0 % hydrochloric acid (HCl). The study covers the inhibitory effect of the before mentioned types of honey in different concentrations (0.5, 1.0, 1.5 and 2.0 %) and the dependence of corrosion processes on the length of the exposure time interval. The preparation method was the same for all samples. After the measurements came the analysis of the results. This included calculations based on empirically determined gravimetric data (changes in sample masses) and the calculated values of inhibitory efficiency and corrosion rate. We also performed a microscopic analysis of the surface of the samples and measurements using a spectroscopic method – infrared spectroscopy (FTIR). In conclusion, based on the experimental work we now know that honey acts as an effective green inhibitor in exposing steel to corrosive medium (17.0 % HCl). For different types of honey efficacy is the trend of efficiency comparable. Already in 0.5 % honey solution, the inhibition rate was more than 50 % and in 2.0 % honey solution the value typically increased above 85 %. In most measurements the highest inhibitory value at a given concentration of honey was achieved at 8 hours of exposure.

Cilj diplomske naloge je raziskati profil in ravnost vroče valjanih trakov. Profil traka predstavlja razliko debeline traka na robu in na sredini po širini. V diplomski nalogi so bili natančneje raziskani vplivi upogiba valjev zaradi delovanja strižnih in upogibnih napetosti, mehanske bombiranosti in termične bombiranosti na profil traka. Da zagotovimo ravnost traka se mora tekom valjanja ohranjati razmerje med debelino na sredini valjanca in na njegovem robu. V primeru, da je odvzem večji na robu pride do robne valovitosti traka, v primeru da pa je odvzem materiala večji na sredini kot na robu, pride do sredinske valovitosti traka. Oblika profila ima v prvih prevlekih, ko je območje ravnosti, kot ga prikazujejo diagrami ravnosti, še dovolj odprto, manjši vpliv na samo ravnost. Ravnost traka se zagotavlja v zadnjih prevlekih z ohranjanjem razmerja debelin na robu in sredini valjanega traka. Meritve smo izvajali na elektro pločevini kvalitete EV12 in kvalitete EV21-P. Skupno je bilo narejenih 10 meritev, za vsako kvaliteto po 5. V prvi fazi eksperimentalnega dela smo merili ravnost oz. valovitost traka tekom valjanja na valjalnem stroju steckel. V drugi fazi pa smo pridobili in uporabili ustrezne parametre za izdelavo matematičnega modela, ki računa bombiranost valjev zaradi delovanja strižnih in upogibnih napetosti ter upošteva mehansko in termično bombiranost valjev. V tretji fazi pa smo na osnovi meritev in izračunov izrisali diagrame ravnosti, katerih rezultati so bili primerjani z opazki iz prve faze. The aim of this diploma thesis is to research profile and flatness of hot rolled strips. The profile of the strip is described as the difference in thickness between the edge of the strip and its middle by width. The effects of bending of the rolls due to shear and bending stresses, the effect of change in the diameter of the work rolls by width due to mechanical and the effect of thermal expansion during rolling were closely studied. In order to ensure the flatness of the rolled material, the ratio between the thickness of the strip in the middle and the edge must remain constant during rolling. In the event that the reduction of thickness is greater on the edge then the middle of the strip, then that results in wavy edges. If the reduction is higher in the middle, then that results in central buckles of the strip. The influence of the strip profile during the first passes is minor as it is shown in diagrams of strip flatness. Flatness of the rolled strip in ensured in the last passes through the rolling mill. Measurements were performed on electric steel of two different grades EV12 and EV21-P. Altogether 10 measurements were made, 5 of each grade. In the first phase of the experiment, flatness or waviness of the strip was being observed during rolling on the steckel rolling mill. In the second phase the parameters for the construction of the mathematical model, that calculates the bending of rolls due to shear and bending stresses while taking into account the change in roll radius due to mechanical grinding and thermal expansion were obtained and used. In the third phase diagrams that show flatness of the strip during each pass were constructed. The results of the third phase were compared with the observations from the first phase of the experiment.

V magistrski nalogi je predstavljena napredna požarna analiza konstrukcije v primeru, ko pride do izbruha požara v jeklenem prizidku, ki je bil naknadno postavljen k obstoječi armiranobetonski proizvodni hali. Nosilna konstrukcija prizidka je pri tem sidrana neposredno v konstrukcijo obstoječega dela. Prizidek pri tem predstavlja ločen požarni sektor. Zaradi raztezanja jekla pri visokih temperaturah med požarom lahko pride do znatnega povečanja sil na stiku obeh delov objekta. V nalogi predpostavljamo, da lahko te pomembno vplivajo tudi na stabilnost obstoječega AB dela hale, čeprav ostaja ta na hladni strani požara, na kar projektanti v vsakdanji inženirski praksi pogosto pozabljajo. Ker teh sil ne moremo določiti s poenostavljenimi računskimi postopki, ki so na voljo v Evrokodu, izbrano konstrukcijo preverimo z napredno požarno analizo. Jekleni del konstrukcije, ki je požaru izpostavljen neposredno, pri tem obravnavamo z geometrijsko in materialno nelinearno analizo po metodi končnih elementov, pri čemer uporabimo volumske končne elemente. Ker so takšne analize pogosto numerično zahtevne, se naloga sočasno ukvarja tudi z možnimi poenostavitvami modela. Zaključki pokažejo, da je povečanje sil na stiku starega in novega dela objekta med požarom res izrazito. Pri tem se lahko osno-upogibna obremenitev znatno poveča, tudi v sicer hladnem AB delu konstrukcije, in sicer do nivoja, ki je primerljiv s tisto, ki odgovarja stalnim oziroma potresnim projektnim stanjem. Dodatno zaključki pokažejo, da bi bila za analizo poleg zelo natančnega naprednega modela mogoča uporaba tudi precej poenostavljene različice modela, ki bi bila na varni strani. Žal bi ta pomenila kar 30 % višje upogibne obremenitve obstoječega AB dela objekta, kar bi lahko vodilo do cenovno manj ugodnih projektantskih rešitev. The master’s thesis presents advanced fire analysis of the construction in a case of a fire outbreak in a steel extension that was later built next to the existing production hall made of reinforced concrete. Load bearing structure of the extension is directly anchored into the construction of the existing part of the hall. The extension represents a separate fire sector. Due to the expansion of steel in case of high temperatures during a fire, a significant increase of forces on a contact of both parts of the building can occur. In the thesis, we assume that these forces can have a significant impact on the stability of the existing part of the hall made of reinforced concrete, although it is situated on the cool side of the fire. Engineers often forget about this in every day engineering practice. As these forces cannot be defined by simplified calculation procedures available in Eurocode, we verify the chosen structure by an advanced fire analysis. A steel part of the construction that is directly exposed to the fire is dealt with using a geometrical and material non-linear finite element analysis using solid finite elements. Such analyses are often numerically demanding, thus at the same time the thesis deals with the possible simplifications of a model. Conclusions reveal that there is really a distinct increase of forces on the contact of a new and old part of the building during a fire. Therefore the axial-bending load can be significantly increased also in otherwise cold part of the construction made of the reinforced concrete, namely to the level that is comparable with the one corresponding to persistent and seismic design state. Furthermore, conclusions reveal that in addition to the very precise construction model, a much simplified version of the model would be possible which would be on the safe side. Unfortunately, this would mean as much as 30 % higher bending loads of the existing part of the building made of a reinforced concrete, which could lead to less favourably solutions in terms of costs.

Okoljsko (EKO) označevanje je eno najpomembnejših orodij za dvig nivoja varovanja okolja. Širjenje okoljskega označevanja je tesno povezano z dognanji podjetij, da skrb za varovanje okolja prinaša tudi dobiček. Rezultat navedenega je pojav različnih deklaracij, zahtev in okoljskih oznak za proizvode, procese in storitve. Uveden je standard ISO 14020 in definicija treh tipov okoljskega označevanja. Ekološka oznaka je lahko na embalaži ali na proizvodih. Naša ocena je, da so vsi trije tipi okoljskega označevanja primerni in uporabni za proizvode in polproizvode iz jekla. V okviru magistrskega dela je izvedena podrobna študija okoljskega označevanja na primeru petnajstih največjih evropskih proizvajalcih jekla. Izveden je pregled in razdelitev okoljskih oznak. Vseh petnajst največjih evropskih proizvajalcev jekla ima pridobljene in veljavne certifikate ISO 9001, ISO 14001 in ISO 50001 ter večji del tudi ISO 16949 in EMAS. Na področju okoljskega označevanja pa je stanje slabo, saj imata le dva izmed njih pridobljeno EKO oznako tipa I, manjši del pa tudi oznake tipa II in III. Environmental (ECO) labelling represents one of the most important tools for environmental protection improvement. Expanse of ECO labelling in the last years is connected with the invention of firms that care for environment can make a profit. The result is the emergence of different declarations, requirements and environmental labels for products, processes and services. The ISO 14020 standard and the definition of three types of environmental labeling have been introduced. The ecological label could be on the packaging or on the products. Our assessment is that all three types of ECO labeling are suitable and useful for steel products and semi-finished products. In the master's thesis, a detailed environmental labeling study was conducted on the case of the fifteen largest European steel producers. An overview and distribution of environmental labels was carried out. All the fifteen largest European steel producers have obtained and validated ISO 9001, ISO 14001 and ISO 50001 certificates, and a large part of ISO 16949 and EMAS. In the area of environmental labeling, however, the situation is extremely poor, as only two of them have obtained the Type I ECO label, and a smaller part of the type II and III designations.

Cilj raziskave je bil ugotoviti primernost izbranih poliuretanskih in epoksidnih lepil za konstrukcijsko lepljenje lesa in jekla. Preizkusili smo štiri poliuretanska lepila COSMO in dve epoksidni lepili ERGO in XEPOX. Kakovost lepilnega spoja smo ovrednotili s testom strižne trdnosti, ki je sledil posameznim postopkom izpostavitve preizkušancev: izpostavitev standardni klimi, z relativno zračno vlažnostjo 65 % in temperaturo 20 °C izpostavitev vlažni klimi s 87 % vlažnostjo in temperaturo 20 °C ter različne izpostavitve (namakanje/kuhanje) v vodi. Rezultati so pokazali, da proučevana poliuretanska lepila z vidika kakovosti lepljenja ne morejo konkurirati epoksidnim lepilom. Proučevani epoksidni lepili sta zagotovili odlično kakovost lepljenja v suhih pogojih ter se izkazali kot pogojno primerni za nekonstrukcijsko rabo v vlažnih pogojih. Za uporabo izbranega lepila v konstrukcijskih aplikacijah je bilo izdano priporočilo, da je potrebno lepilni spoj dodatno ojačati z vijaki, ki bi zagotovili zanesljivost spoja v primeru nastopa izjemne vlage ali požara. The aim of the research was to determine the suitability of selected polyurethane and epoxy adhesives for structural bonding of wood and steel. We tested four polyurethane adhesives COSMO and two epoxy adhesives ERGO and XEPOX. The quality of the adhesive bond was evaluated by a shear strength test followed by one of the following exposure tests of the specimens: exposure to the standard climate with 65 % relative humidity and a temperature of20 °C exposure to humid climate with 87 % humidity and a temperature of 20 °C and various exposures (soaking/cooking) in water. The results showed that the polyurethane adhesives studied in this work cannot compete with epoxy adhesives in terms of bonding quality. The epoxy adhesives provided excellent bonding properties in dry conditions,and proved to be potentially suitable for non-structural use in humid conditions. However, in order to use the selected adhesives in construction applications, it is recommended that the adhesive joint should be additionally reinforced with screws to ensure the reliability of the joint in the event of exceptional moisture or fire.

Diplomska naloga obravnava projektiranje jeklenih konstrukcij na mejna stanja uporabnosti v skladu s standardi Evrokod. Najprej so na splošno definirana mejna stanja nosilnosti in uporabnosti, ki jih predpisuje osnovni standard. Nato je prikazana izvedba globalne analize jeklenih konstrukcij. V glavnem delu so prikazani kriteriji za kontrolo mejnih stanj uporabnosti za jeklene konstrukcije, v katerem se osredotočimo na slovenski nacionalni dodatek k osnovnem standardu in na priporočila AISC za projektiranje jeklenih konstrukcij na mejna stanja uporabnosti. Na primeru jeklenega okvirja in strešne lege je prikazano projektiranje z različnimi pristopi. Prikazano je projektiranje z upoštevanjem plastične in elastične globalne analize z upoštevanjem teorije drugega reda. Glede na izbor globalne analize so prikazane ustrezne kontrole mejnih stanj. This Graduation Thesis deals with the design of steel structures for the verification of serviceability limit states as imposed by Eurocode standards. Firstly, the general definitions of ultimate and serviceability limit states are shown, which are defined in the basic Eurocode standard. Next, the implementation of the global analysis of steel structures is presented. The main part lists serviceability design criteria for steel structures which are obtained from the Slovenian National Annex to standard EN 1990 and criteria from AISC Design Guide. Numerical example demonstrates the design of steel frame and steel purlin, where different design approaches are adopted. Design using the plastic and elastic global analysis considering the second order theory is presented. The appropriate verifications of the limit states are demonstrated following the selected design approach.

Jeklena oklepna pločevina PROTAC 500M, izdelana v proizvodnih obratih največjega slovenskega proizvajalca jekla, se na svetovni trg dobavlja v poboljšanem stanju. Nizko temperaturno popuščanje je izvedeno pri temperaturi 200°C, ki je zaradi nizke temperature zahteven proces toplotne obdelave. V okviru diplomskega dela so bile določene toplotne lastnosti jekla PROTAC 500M, ki so osnova za načrtovanje nizkotemperaturne toplotne obdelave. Z instrumentom za analizo toplotnih lastnosti Hot Disk TPS 2200 smo v skladu s standardom ISO 22007-2 določili toplotno prevodnost, specifično toploto in temperaturno prevodnost jekla pri sobni temperaturi in na temperaturnem intervalu med sobno temperaturo in temperaturo 480°C. Na osnovi izmerjenih toplotnih lastnosti ter izvedenih toplotno tehničnih izračunov je bila izvedena validacija dobljenih parametrov v neposrednem industrijskem okolju. The armour steel sheet PROTAC 500M, made in the production plants of the largest Slovenian steel producer, is supplied to the world market in quenched and tempered condition. Low temperature tempering is processed at a temperature of 200°C, that is due to low temperature very demanding process of heat treatment. The thermal properties of steel PROTAC 500M are the basis for the design of low temperature heat treatment and they were determined within this thesis. Thermal conductivity, specific heat and temperature conductivity of the steel at room temperature and at a temperature interval between room temperature, and the temperature of 480°C were determined using the Hot Disk TPS 2200 thermal properties analysis instrument in accordance with standard ISO 22007-2. Validation of the obtained parameters in the direct industrial environment was carried out on the basis of the measured thermal properties and the performed termotechnical calculations.

V raziskavi smo proučevali kakovost epoksidnega lepilnega spoja med lesom in jeklom. Ugotavljali smo vpliv priprave površine jekla na strižno trdnost lepilnega spoja. Površine jekla so bile obdelane na štiri različne načine, in sicer neobdelana, grobo brušena, polirana in žlebičeno polirana površina. Za lepljenje smo uporabili dvokomponentno epoksidno lepilo Xepox 40. Lesene lamele so bile izdelane iz smrekovega lesa. Ko smo lesene in jeklene lamele zlepili in je lepilo utrdilo, smo polovico preizkušancev izpostavili standardni klimi, polovico pa smo 24 ur namakali v vodi. Nato smo opravili test strižne trdnosti po standardu SIST EN 205:2003. Po porušitvi preizkušanca smo ocenili delež loma po lesu. Ugotovili smo, da na strižno trdnost lepilnega spoja vpliva predhodna obdelava površine jekla. Med preizkušanci, ki so bili izpostavljeni standardni klimi, so najboljše rezultate dosegli preizkušanci, pri katerih je bila površina jekla polirana, medtem ko so po 24-urnem namakanju največjo strižno trdnost dosegli preizkušanci, ki so imeli neobdelano površino jekla. V splošnem je bila strižna trdnost spoja namočenih preizkušancev bistveno manjša kot klimatiziranih preizkušancev. Na osnovi rezultatov lahko zaključimo, da je dvokomponentno epoksidno lepilo Xepox 40 primerno za lepljenje lesa in jekla za uporabo v suhih pogojih. The research study focused on the quality of the epoxy adhesive bond between wood and steel. We studied the influence of surface preparation of steel on shear strength. The steel surfaces were prepared in 4 different ways: untreated, roughly brushed, polished and guttered polished. Two-component epoxy adhesive Xepox 40 was used. Wooden lamellas were made from spruce wood. When the wooden and steel lamellas were glued and the adhesive was cured, we exposed them to two different conditions (standard climate and soaking in water for 24 hours). We performed our next test according to the SIST EN 205:2003 standard. After the test, we estimated the wood failure percentage. As expected, the shear strength was affected by the preliminary surface preparation of steel. Out of the test specimens that were exposed to the standard climate, the best results were achieved by the one with polished steel surface, while after 24 hours of soaking in water, the highest shear strength was achieved by the test specimens with untreated steel surface. In general, the shear strength of test specimens that were exposed to water was significantly lower than the air-conditioned specimens. Based on these results, it can be concluded that the two-component epoxy adhesive Xepox 40 is suitable for gluing wood and steel for use in dry conditions.

V okviru diplomskega dela je obravnavana metoda vrednotenja življenjskega cikla LCA, sodobnega orodja za analizo, vrednotenje in oceno življenjskega cikla proizvodov, procesov in storitev. Kratko je predstavljen standard upravljanja z okoljem ISO 14001, ter standardi družine ISO 14040, splošna načela in pravila za vodenje in vrednotenje študije LCA, ter uporaba na področju proizvodnih tehnologij s posebnim poudarkom na področju proizvodnje visokokakovostnih jekel za protibalistično zaščito, na primeru jekla PROTAC 500 največjega slovenskega proizvajalca jekla. V okviru dela sta izvedeni kompleksna analiza in vrednotenje življenjskega cikla ter SWOT analiza debele pločevine iz jekla PROTAC 500. V okviru izvedene študije smo analizirali in ovrednotili emisije v zrak pri treh glavnih procesih izdelave jekla PROTAC 500 v neposrednem industrijskem okolju proizvodnih obratov največjega slovenskega proizvajalca jekla: procesu izdelave jekla v električni obločni peči in vlivanje v slabe na napravi za kontinuirno litje, ogrevanju slabov v potisni peči in vročem valjanju slabov na plošče debelin od 6 do 25 mm. Količine emisij so logično visoke in so seveda direktno povezane s količino proizvedenega jekla. Količine proizvedenih jeklenih plošč so bile v letih 2010, ko se je pričelo z industrijsko proizvodnjo jekla PROTAC 500, pa do leta 2015 do maksimalno 100 ton na letnem nivoju. V letu 2016 je proizvodnja narasla na 1487 ton, v letu 2017 pa je že presegla mejo 2000 ton na letnem nivoju. Izvedeno delo je prispevek k dvigu produktivnosti in izboljšanju kakovosti ter doprinos k področju varstva okolja in zmanjšanju porabe energije in surovin. In the context of the graduation thesis, the method of life cycle assessment LCA, a modern tool for analysis, evaluation and assessment of the life cycle of products, processes and services, is discussed. The ISO 14001 environmental management standard and ISO 14040 family standards, the general principles and rules for managing and evaluating the LCA study, and the use in the field of production technologies with special emphasis on the production of high-quality steels for anti-ballistic protection, in the case of PROTAC 500 steel by the largest Slovenian producer of steel, are presented briefly. Within the framework of the thesis, a complex analysis and evaluation of the life cycle and SWOT analysis of thick sheet metal made of PROTAC 500 steel were made. Within the framework of the conducted study we analysed and evaluated the emissions into the air in the three main processes of PROTAC 500 steel production in the direct industrial environment of the production plants of the largest Slovenian steel producer: the steel production process in the electric arc power furnace and the casting into slabs on the continuous casting device, reheating of slabs in push-type furnace and hot rolling of slabs on plates of thickness from 6 to 25 mm. Emissions are logically high and, of course, directly related to the amount of steel produced. The quantities of steel plates manufactured in years from 2010, when the industrial production of PROTAC 500 steel started, to 2015 were up to a maximum of 100 tons per year. In 2016, production increased to 1487 tonnes, and in 2017 it already exceeded the 2000 tonnes on an annual level. The thesis is a contribution to raising productivity and improving quality and a contribution to environmental protection and reduction of energy, and raw materials consumption.

S pojavom razpok nastajajo v armiranobetonskem kompozitu različna deformacijska in napetostna stanja, ki jih ni mogoče enostavno obravnavati in analizirati njihov vpliv na zmanjševanje togosti in nosilnosti obravnavanega konstrukcijskega elementa. Namen pričujočega magistrskega dela je študija vpliva razpokanega prereza na togost armiranobetonskega nosilca in njegovo končno nosilnost. Poudarek študije temelji na izbiri matematičnih modelov za opisovanje materialnih lastnosti betona in jekla s katerimi želimo oceniti nelinearno obnašanje. Osrednji del magistrskega dela obravnava analizo različnih računskih modelov enostavnega prostoležečega armiranobetonskega nosilca z deformacijsko metodo končnih elementov. Pri tem je bil upoštevan vpliv materialne nelinearnosti, s katero smo simulirali razvoj in širjenje razpok v armiranobetonskem elementu. Študija računskih modelov je bila izvedena s pomočjo programa SOFISTIK®. Obravnavani so bili trije različni matematični modeli z uporabo linijskih in ploskovnih končnih elementov. V zaključku je bila izvedena eksperimentalna verifikacija obnašanja realne enostavne konstrukcije prostoležečega nosilca s primerjavo rezultatov matematičnih modelov. V ta namen smo pripravili šest nosilcev, ki smo jih v laboratoriju nato preizkušali s pomočjo štiri točkovnega upogibnega preizkusa. Merili smo vertikalne pomike ob kontrolirano povečevani obremenitvi, ter sprotno opazovali ter evidentirali stanje razpok. Eksperimentalno verifikacijo smo zaokrožili z enoosnimi tlačnimi preizkusi na standardiziranih kockah in nateznimi preizkusi na armaturnih palicah. Osnovni namen magistrskega dela je bil primerjava analitičnih izračunov z eksperimentalnimi rezultati. Primerjava rezultatov je pokazala, da je z uporabo metode končnih elementov in upoštevanjem materialne nelinearnosti možno zadovoljivo opisati pojav in širjenje razpok v armiranobetonskem nosilnem elementu. With the appearance of cracks, there are various deformation and stress states in the reinforced concrete composite, which can not be easily considered and analyzed for their influence on reducing the rigidity and load capacity of the structural element concerned. The purpose of the present master's thesis is the study of the influence of the cracked cross section on the stiffness of the reinforced concrete beam and its load capacity. The emphasis of the presented study is based on the choice of mathematical models for describing the material properties of concrete and steel with which we want to evaluate nonlinear behavior. The main part of the master's thesis deals with the analysis of various computational models of a simple, reinforced concrete beam with a deformation method of finite elements. In this regard, the influence of material nonlinearity was taken into account, with which we simulated the development and spread of cracks in the reinforced concrete element. The study of mathematical models was carried out using the SOFISTIK® program. Three different mathematical models were considered using beam and plane finite elements. In conclusion, an experimental verification of the behavior of a real simple beam was performed by comparing the results of mathematical models. For this purpose six beams were prepared and analyzed in the laboratory using a four-point bending test. Transverse displacements with a controlled increasing load were measured. Simultaneously the cracks and their conditions were observed and recorded. The experimental verification was completed by single-axial pressure tests on standardized cubes and tensile tests on reinforcing bars. The main purpose of the master's thesis was to compare analytical calculations with experimental results. Comparison of the results revealed that using the finite element method, taking into account material nonlinearity, it is possible to describe satisfactorily the occurrence and spread of cracks in the reinforced concrete element.

V diplomskem delu je izvedena zasnova in dimenzioniranje preproste jeklene hale. Prvi del predstavlja obtežbe, ki delujejo na skladiščno halo. Na podlagi slednjih je v drugem delu izdelana statična analiza posameznih elementov kot so prečke, stebri, povezja… V tretjem delu so dimenzionirani pomembnejši stiki, kot so stik prečke in stebrov, stik natezne diagonale s stebrom, stik s temeljem. Izrisani so tudi detajli stikov in pozicijski načrti. Poudarek na nalogi je predvsem pretežno členkasta zasnova stikov pri konstrukciji. Dimenzioniranje poteka po trenutno veljavnih Evrokod standardih. The diploma thesis focuses on the design and dimensioning of a steel warehouse with a simple structural system. The first part presents the loads that are causing stress in the structure. On the basis of these loads, a static analysis of individual elements is made. The analysis, the design and the generation of numerical models of columns, purlins, rafters, bracing systems present the second part of the thesis. In the third part the main focus is in the detailing of the most important joints. The following joints are designed: beam-to-column joint, joint of brace member to the column, column base. The design of the foundation is performed as well. The position drawings and details of joints are presented in the annex. The design is performed according to Eurocode standards.

V diplomski nalogi je predstavljena primerjava požarne odpornosti jeklenega in aluminijastega linijskega nosilca. Predvideni nosilec je del fasadne konstrukcije, ki prenaša obremenitev lastne teže konstrukcije in vpliva vetra. V prvem delu naloge so predstavljena splošna pravila varnosti konstrukcij pred požari in zakonodaja, ki narekuje varnostne zahteve. Nato so predstavljene splošne mehanske in toplotne lastnosti jekla ter aluminija pri povišani temperaturi. V osrednjem delu so opisane glavne kontrole nosilnosti, ki so povzete po standardu Evrokod 3 in Evrokod 9. Pri tem so izpostavljene glavne razlike dimenzioniranja med obema materialoma. Sledita računska primera požarne odpornosti jeklenega in aluminijastega nosilca izpostavljenega standardni požarni krivulji ISO 834. V zaključku naloge so predstavljene ugotovitve rezultatov, ki so bili dobljeni v računskem delu naloge. This thesis studies and compares the fire resistance of steel and aluminium planar beams. Analyzed beam is part of a facade construction that transmits the load of its own weight and the influence of the wind. The introduction describes the general rules for structural fire safety and safety regulation. Furthermore, the general mechanical and thermal properties of steel and aluminium at an elevated temperature are presented. The main focus of the thesis is on the design rules which are summarized after the Eurocode 3 and Eurocode 9 standards. The main differences in designing between the two materials are also highlighted. Moreover, fire resistance calculations of the steel and aluminium beam according exposed to the standard fire curve ISO 834 are shown. The conclusion presents the results obtained in the computational part of the thesis.

Lepljeni lamelirani nosilci se uporabljajo v konstrukcijske namene. Potrebno jih je spajati z jeklenimi deli. Vijačenje jeklenih delov lahko zamenjamo z lepljenjem in tako povečamo togost spoja. V raziskavi smo proučevali kakovost poliuretanskega lepilnega spoja med lesom in jeklom. Uporabili smo tri različna enokomponentna poliuretanska lepila: COSMO PU–100.110, COSMO PU–180.150 in COSMO PU–190.110. Lesene lamele smo izdelali iz smrekovine in jih zlepili z jeklenimi lamelami. Preizkušance smo za 6 dni izpostavili trem različnim pogojem in sicer: standardni klimi, vlažni klimi ter namakanju v vodi. Izvedli smo test natezno strižne trdnosti spojev s preklopom po standardu SIST EN 205:2003 in določili delež loma po lesu. Kakovost lepilnega spoja med lesom in jeklom je bila odvisna od uporabljenega poliuretanskega lepila. Najboljše se je izkazalo lepilo COSMO PU–190.110, ki je po izpostavitvi standardni klimi doseglo strižno trdnost 8,49 N/mm2 in 53 % delež loma po lesu. Na kakovost lepilnega spoja je prav tako vplivala priprava preizkušancev pred testiranjem. Najboljše so se odrezali preizkušanci izpostavljeni standardni klimi in najslabše preizkušanci namočeni v vodo. Lepili COSMO PU–190.110 in COSMO PU–180.150 sta se izkazali kot uporabni za lepljenje jekla in lesa v suhih pogojih (standardna klima). Lepilo COSMO PU–100.110 se je izkazalo kot neuporabno za lepljenje jekla in lesa v proučevanih pogojih. Glued laminated beams are used for construction purposes. They need to be connected with steel parts. Instead of screws, adhesive can be used to increase joint stiffness. This research study focused on the quality of the polyurethane adhesive bond between wood and steel. Three different one-component polyurethane adhesives were used: COSMO PU–100.110, COSMO PU–180.150, and COSMO PU–190.110. The wooden lamellas were fashioned from spruce wood and bonded with steel lamellas. For six days, the test specimens were exposed to different conditions: standard climate, moist climate, and soaking in water. A test of the tensile shear strength of lap joints, determining the wood failure percentage, was performed according to the SIST EN 205:2003 standard. The quality of the adhesive bond between the steel and wood depended on the polyurethane adhesive used. The best results were achieved with COSMO PU–190.110, which after exposure to the standard climate reached a shear strength of 8.49 N/mm2 and 53% wood failure. The preparation of the test specimens prior to the test also affected the quality of the adhesive bond. The best results were achieved by the test specimens exposed to the standard climate the worst results by those soaked in water. The COSMO PU–190.110 and COSMO PU–180.150 adhesives proved to be useful for bonding steel and wood in dry conditions (standard climate). In contrast, the COSMO PU–100.110 adhesive proved to be useless for bonding steel and wood in the studied conditions.

Magistrsko delo obsega projektiranje jeklene hale v skladu s standardi Evrokod. Projektiranje jeklene hale obsega zasnovo glavne nosilne konstrukcije, razčlenitev obtežb, dimenzioniranje ter detajlne izrise konstrukcije. Določene so stalne, spremenljive in seizmične obtežbe, ki smo jih upoštevali pri projektiranju, pri čemer je poudarek na snežni obtežbi, predvsem na obtežbi snega na strehah, ki mejijo na višje objekte ali so blizu njih. Hala je zasnovana ravno tako, da je izpostavljena tovrstni snežni obtežbi. Dimenzioniranje jeklene hale je opravljeno s programom Scia Engineer. Prvotno so dimenzionirane kontinuirane strešne lege, katere so nato v prostorskem numeričnem modelu namenjene realnemu raznosu vertikalne obtežbe. Za statične obremenitve je dimenzioniranje glavne nosilne jeklene konstrukcije izvedeno na prostorskem numeričnem modelu z nelinearno globalno analizo ob upoštevanju teorije drugega reda in nepopolnosti. Medtem ko je za seizmične obremenitve, izvedena modalna analiza s spektri odziva. Jeklena hala je za seizmične obremenitve projektirana kot konstrukcija z majhnim sipanjem energije notranje sile so izračunane z elastično globalno analizo, dimenzioniranje pa je opravljeno v skladu s standardi iz skupine Evrokod 3 (brez metode načrtovanja nosilnosti). V zadnjem delu magistrske naloge so dimenzionirani spoji. This master's thesis deals with designing a steel hall in line with Eurocodes. The hall design involves the planning of the main load-bearing construction, a breakdown of loads, dimensioning and detailed construction drawing. Moreover, it determines continuous and changeable loads as well as seismic loads, all of which have been taken into account in the design process. Special attention was devoted to snow loads, specifically on the roofs bordering or close to taller buildings. The hall is designed in a way that causes exposure to snow loads. The dimensioning part was conducted using Scia Engineer software. Initial dimensioning included continuous purlins, which serve as real distribution of vertical loads. As for static loads, the dimensioning of the main steel construction was carried out on a spatial numerical model using nonlinear global analysis, while taking into account the second-order theory with imperfections. A modal response-spectrum analysis was conducted for seismic loads. The steel hall was designed as a construction with low energy dissipation. Internal forces were calculated using elastic global analysis, while the dimensioning portion corresponds to Eurocode 3 standards (without capacity design rules). Dimensioning of the selected joints is included in the final part of the master's thesis.

The correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated in this study. Within the concept of physical mesomechanics, the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material. Characteristic stages are analyzed for various modes of failure, moreover, typical levels of loading and oscillation periods, etc. are determined. Relations between low temperature derived through this test, microstructures and Charpy (V-notch) toughness test results are also discussed in this paper.

V diplomski nalogi je obravnavano obnašanje dveh upogibno obremenjenih sovprežnih nosilcev. Prvi je sestavljen iz IPE140 jeklenega nosilca in enosmerno lepljene (GL) lesene plošče, drugi pa prav tako iz IPE140 nosilca in križno lepljene (CLT) plošče. Naloga obravnava postopek izdelave in sestavljanja nosilcev, pripravo na test in upogibna testa. Predstavljeni so rezultati preizkusov in obnašanje nosilcev v elastičnem območju na podlagi geometrijskih in materialnih karakteristik, določenih iz izmerjenih podatkov na testu. Iz povesov in po This thesis deals with experimental tests of two simply supported composite beams (steel - timber) loaded in bending. The first beam is assembled of a steel beam IPE140 and a glued laminated (GL) timber plate. The second beam has equal steel cross-section and a cross-laminated timber (CLT) plate. The thesis focuses on the manufacturing and construction procedures of the beams, the preparation for testing and on the analysis of test results. The missing material properties are calculated from the test results. The degree of shear connection is calculated from the test results using the

Določali smo dejanske fizikalne lastnosti različnih jekel. V ta namen smo uporabljali univerzalni hidravlični aparat, programsko opramo LabVIEW in Microsoft Excel. Testirali smo jekla z oznakami Č.0211, Č.3999, Č.1531, Č.4320 in vzmetno jeklo. Za vsako jeklo smo zaradi možnega odstopanja in eksperimentalnih napak izvedli tri ponovitve meritev. Opisali smo teste, ki smo jih izvedli in prikazali potek računanja. Iz meritev smo izračunali vrednosti meje elastičnosti, meje plastičnosti, modula elastičnosti, razteznosti in natezne trdnosti. Iz literaturnih podatkov o vsebnosti kemijskih elementov teh petih vzorcev jekel, smo lahko sklepali o lastnostih jekel. Dobljene rezultate smo primerjali s podatki v strokovni literaturi. We determined the actual mechanical properties of different types of steel. To accomplish this we used a universal hydraulic testing machine, computer software called LabVIEW and Microsoft Excel. We tested steels called Č.0211, Č.1531, Č.3999, Č.4320 and spring steel, according to JUS. To avoid the possibility of measurement errors, we conducted the same experiment on each type of steel three times. We described the experiments performed on the steel samples, as well as noted the process of calculating the elastic limit, yield point, elasticity modulus, ducility and ultimate tensile strength. We were able to determine the mechanical properties of the examined steel samples by studying which chemical elements were bonded inside the steel samples. We compared the calculated data to data found in official literature.