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The study presents possible savings resulting from the use of deep-penetration welding processes in the fabrication of welded structures. The study-related tests revealed 80% savings of filler metals and the 50% reduction of welding distortions without compromising the maximum load-carrying capacity of welded joints. The tests involved steel grades S355J2, S460NL, S700MC, S690QL and 450HBW (Hardox) having thicknesses restricted within the range of 8 mm to 20 mm as well as filler metal grades G4Si1 and G69.

The study contains quantitative conditions and limitations of the use of butt, fillet and butt-fillet welds in modern welded constructions. Examples of improper use are given. Calculated loss of material and capacity structures associated with the use of fillet welds with a convex face, their asymmetry, as well as the benefits of in-depth penetration obtained by hybrid or other, leading to the achievement of butt welds and butt-fillet welds with high-efficiency welding technologies. A list of the requirements for the correct use of fillet welds and features differing from butt, butt-fillet and fillet welds is given.

Friction stir processing (FSP) was used to modify the surface layer of the AZ91 magnesium alloy. The treatment was carried out using a jet cooling nozzle, generating a stream of cold air and enabling intensive cooling of the friction stir processed (FSPed) zone. Single-pass FSP was carried out using a tool rotational speed of 500 rpm and travel speed of 30 mm/min. The treatment was conducted using a truncated cone-shaped tool with a threaded side surface. Strong grain refinement and microstructural changes typical for FSP were found in all the samples. Very fine, equiaxed recrystallized grains dominated in the stirring zone. In the samples modified with the jet cooling nozzle, greater grain refinement was obtained than in the case of naturally-cooled material. The average grain size in the surface part of the stirring zone was 1.4 µm and 9 µm in the samples with air cooling and with natural cooling, respectively. Both the naturally-cooled specimen and air-cooled specimen were characterized by a distinctly higher hardness than the base material. The average Vickers hardness in the stirring zone was 91 HV0.1 in the FSPed sample with the air-cooling system and 85.5 HV0.1 with natural cooling, respectively. The average Vickers hardness of the as-cast alloy was 64 HV0.1. Slightly higher wear resistance of the FSPed samples using a jet cooling nozzle was found in relation to the naturally-cooled sample. Based on the conducted research, high efficiency of the jet cooling nozzle in cooling the modified zone during friction stir processing was found.

A rolled plate of 7075 aluminum alloy was friction-stir-processed (FSP) with simultaneous cooling by an air stream cooled to −11 °C with a jet cooling nozzle. Two variants of air blowing were used: at an angle of 45° to the sample surface and at an angle of 90°. The reference material was a sample subjected to analogous treatment but naturally cooled in still air. The microstructural tests revealed strong grain refinement in all the samples, with higher grain refinement obtained in the air-cooled friction-stir-processed samples. For the naturally cooled samples, the average grain size in the near-surface area was 7.6 µm, while for the air-cooled sample, it was 1.4 µm for the 45° airflow variant and 3.2 µm for the 90° airflow variant. A consequence of the greater grain refinement was that the hardness of the air-cooled friction-stir-processed samples was higher than that of the naturally cooled samples. The improvement in abrasive wear resistance was achieved only in the case of the friction-stir-processed specimens with air cooling. It was found that the change in the air blowing angle affects not only the degree of grain refinement in the stirring zone, but also the geometrical structure of the surface. In all the samples, FSP caused redistribution of the intermetallic precipitates combined with their partial dissolution in the matrix.

In this study, surface remelting treatment of the AZ91 magnesium alloy by means of welding using a non-consumable electrode in an inert gas shield was carried out. Three variants of surface treatment were used, i.e. the single torch variant with a single heat source without cooling down the samples, the single torch variant with a single heat source and a cooling system with liquid nitrogen, and the double welding torch variant with a double heat source in the torches operating in a tandem configuration. Experimental verification of the applied apparatus solutions was based on both macro- and microstructural assessment of the obtained effects. Comparative analysis of the variants used and the obtained microstructural results allowed the authors to indicate the deficiencies and limitations of particular solutions and to single out the best solution that would be useful for modifying the surface layers of magnesium alloys, as well as other materials having a strong oxygen affinity.

The samples of the as-cast AM60 magnesium alloy were subjected to Friction Stir Processing (FSP). The effect of FSP on the microstructure of AM60 magnesium alloy was analyzed using optical microscopy and X-ray analysis. Besides, the investigation of selected properties, i.e. hardness and resistance to abrasion wear, were carried out. The carried out investigations showed that FSP leads to more homogeneous microstructure and significant grain refinement. The average grain size in the stirred zone (SZ) was about 6-9 μm. in the thermomechanically affected zone (TMAZ), the elongated and deformed grains distributed along flow line were observed. The structural changes caused by FSP lead to an increase in microhardness and wear resistance of AM60 alloy in comparison to their non-treated equivalents. Preliminary results show that friction stir processing is a promising and an effective grain refinement technique.

7075 aluminum alloy in the T6 state was subjected to surface remelting treatment using Gas Tungsten Arc Welding (GTAW). The changes in the material microstructure were examined by means of light microscopy, scanning electron microscopy and EDS. Moreover, profilometric tests and comparative measurements of material hardness in the state before and after the treatment were conducted. In the remelted layer strong microstructure refinement and the disappearance of microstructure banding were found. A fine dendritic microstructure was dominant in the remelted zone. Use of the GTAW method reduced the number of intermetallic precipitates in the surface layer. A consequence of dissolving the precipitates was a decrease in the hardness of the material in relation to the hardness before the modification. All the samples were characterized by the presence of a remelted zone, a narrow partially remelted zone and a wide heat affected zone. With an increase in the heat source travel speed, and consequently less heat entering the remelted material, the dimensions of the individual zones decreased. The conducted research showed that GTAW technology can be used in the surface remelting treatment of aluminum alloys and can be a competitive solution in comparison to other technologies.

The article presents the results of experimental studies aimed at comparing the welding conditions and technological properties of butt joint welding in the PG position using the innovative low-energy variant of the MAG method – SpeedRoot, with conventional TIG welding in the PF position. The productivity of both welding processes has been evaluated, as well as the dynamic characteristics of power sources and the macrostructure of obtained joints.

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

W artykule przedstawiono unikatową odmianę metody spawania MAG puls ze zmienną polaryzacją łuku – proces ColdWeld. Omówiono charakterystykę przebiegu tego procesu oraz występujące w nim zjawiska cieplne. Wskazano głównie obszary jego zastosowania, a także korzyści wynikające z wdrożenia tego procesu do produkcji. Abstract The article presents a unique welding method (MAG pulse with a changing arc polarity – the ColdWeld process). Describes the characteristics of this process and its thermal phenomena. Also shows benefits and main areas of implementation of this process in production

The primary objective of the study was to adapt the GTAW (Gas Tungsten Arc Welding) technique for the purposes of the surface remelting processing of non-conductive plasma sprayed coatings. Modification concerned the surface layer of complex oxide compositions based on ZrO2 and Al2O3, which had been applied onto a steel substrate using the plasma spraying technique. In the course of research it was demonstrated that the process of surface remelting of non-conductive oxide coatings may be successfully conducted using welding sources of heat provided that the standard welding station is previously redesigned and additionally equipped. The methodological and apparatus-related work undertaken led to the development and construction of a welding set with a free independent arc, in which the active participation of the oxide coating in the creation of the electric arc and its stabilisation has been eliminated. The effects of the remelting treatment on the structure of the plasma sprayed coatings have been investigated. The microstructures of both the as-deposited and the remelted coatings were observed by optical microscope and scanning electron microscope (SEM). Observation of the remelted coating structure allowed to distinguish areas with characteristic structural and morphological effects and changes in the structure thereof. On the basis of regularities noted and observations made, a zonal model of the remelted coating structure was put forward and elaborated.

Dotychczasowe badania nad geometrią tzn. kształtem pól poprzecznych oraz pobocznic i opór narzędzi do zgrzewania FSW/FSSW (FSW-Friction Stir Welding, FSSW – Friction Stir Spot Welding) przebiegają zazwy- czaj metodą prób i błędów oraz idei wynikłych z różnego rodzaju przypadków badawczych. Niniejszy artykuł może być podstawą matematycznego uporządkowania typoszeregów narzędzi przeznaczonych do zgrzewania materiałów o różnych właściwościach mechanicznych a szczególnie plastyczności. Analysis of tool structure and development of tool geometry for joining metallic alloys using FSW methods Abstract The vast majority of research into FSW/FSSW welding tool geometry i.e. the shape of pin and shoulder in horizontal and vertical planes is based on trial and error approach and ideas derived from different case studies. This work may be the basis for mathematical classification of the geometries of tools that are used for joining materials of different mechanical properties, in particular plasticity.

Ocena ciepla wprowadzonego do zlącza spawanego, szczegolnie na etapie opracowywania technologii spawania, czy monitorowania procesu spawania coraz cześciej obejmuje bezstykowe metody pomiaru temperatury za pomocą pirometrow, termografow czy systemow termowizyjnych. Jednak pomiar promieniowania podczerwonego wyemitowanego przez nagrzane cialo związany jest z szeregiem uwarunkowan, ktorych nieznajomośc moze prowadzic do niewlaściwej oceny wartości temperatury badanego obiektu. Niniejsze opracowanie przybliza niektore aspekty, związane z monitorowaniem procesow cieplnych towarzyszących lączeniu metali z wykorzystaniem technologii spawalniczych. Przedstawiono rowniez przyklad mozliwości zastosowania termowizji do rejestracji rozkladu temperatury wzdluz drutu elektrodowego podczas spawania impulsowego w oslonie gazow ochronnych. Monitoring of Welding Thermal Processes Abstract Contactless testing which allows the assessment of the temperature using pyrometer, thermograph and vision systems are used increasingly to evaluate the heat input into weld, especially during the develop- ment of welding procedure or monitoring of welding. However, the measurement of infrared radiation emitted by a heated object is dependent on many conditions ignorance of which might lead to the incorrect evaluation of the temperature value. The following work introduces some aspects of thermal processes monitoring which accompany metal joining with the use of welding technologies. The article presents the example of applications of thermovision to register of the temperature distribution at the welding electrode tip during GMAW-P.

W artykule przedstawiono nową odmianę metody MMA UP w technice MICOR przeznaczoną do wykonywnia spoin pachwinowych w pozycji PF i PH stali niestopowych. Opisano budowę inwertorowych zasilaczy spawalniczych. Zaprezentowano zewnętrzne charakterystyki statyczną i dynamiczną prezentowanego urządzenia. Opisano wpływ właściwości urządzenia na funkcjonowanie odmiany UP MMA MICOR. Scharakteryzowano spoiny wykonane w technice UP MICOR oraz porównano ich właściwości do spoin wykonanych tradycyjną metodą MMA w pozycji PF. Abstract This paper presents the results of experimental studies devoted to welding of low alloy steel in PF and PH position with new UP MMA MICOR technology. The construction of inverter welding power source has been discussed. The external static and dynamic characteristics of presented apparatus have been described. In the second part of the paper the effect of the properties of the device on the operation of UP MMA MICOR solution has been shown. The welds obtained by UP MMA MICOR technique has been characterized and their properties were compared with welds made using conventional MMA method in PF position.

Praca zawiera opis metodyki obliczeń nośności statycznej spoin pachwinowych dwoma dopuszczonymi przez Eurokod 3 sposobami: kładowym (uproszczonym) i kierunkowego rozkładu naprężeń, opartym na wszechstronnych badaniach wytrzymałości spoin i hipotezie HMH. Przedstawiono przykład wyznaczania naprężeń obliczeniowych w spoinie pachwinowej obciążonej trzema wzajemnie prostopadłymi siłami, wywołującymi siedem różnych rodzajów naprężeń. Dokonano ich rozkładu, a następnie superpozycji w kluczowych punktach spoiny. wyjaśniono dlaczego metoda kładowa (uproszczona) prowadzi do obliczeniowego przewymiarowywania spoin pachwinowych. Abstract The paper describes methodology for calculation of fillet joint load capacity using two approaches allowed by Eurocode 3: projection method (simplified) and method of directional stress distribution that is based on comprehensive weld strength tests and HMH hypothesis. The work presents the example of stress calcula- tion for fillet joints loaded with three forces acting along mutually perpendicular directions that produce stresses of seven different kinds. The stress decomposition and subsequently stress superposition in key weld points was performed. It was explained why projection method (simplified) leads to computational overestimation of fillet joints.

W artykule przedstawiono wyniki badan doświadczalnych wlaściwości uzytkowych nowoczesnego spawalniczego źrodla inwertorowego wykonanego w technice MICOR. Rozni sie ono od klasycznego zasilacza z przemianą czestotliwości tym, ze po stronie pierwotnej zastosowano dwa falowniki oraz dwa transformatory wysokiej czestotliwości polączone w jeden uklad elektryczny. Zaprezentowano zewnetrzne charakterystyki statyczne i dynamiczne oraz wybrane wlaściwości spoin. New features of the MMA welding inverter built in MiCOR technology The paper presents the results of experimental studies of the properties of modern welding power source made in technology MICOR. It differs from the conventional inverter that on the primary side there are two inverters and two high frequency electric transformers combined in one electrical system. This paper also presents the external characteristics of the power source an selected properties of welds.

The paper presents the research work devoted to welding of root pass in PJ position using the new MAG- SpeedRoot welding method. The conditions of welding and results of obtained root passes by MAG-SpeedRoot method were compared to conventional welding methods. The MAG-SpeedRoot method has been developed by Lorch (Germany) company specifically for welding of root passes in PG position. The purpose of this work was to implement the MAG-SpeedRoot technology of root pass welding in butt welded steel pipelines at JT Zakład Budowy Gazociągów plant in Warsaw, Poland. As the result, this technology has been certified by the UDT certification body first time in history. in polish Zastosowanie metody MAG-SpeedRoot do spawania ściegu graniowego spoin czołowych w połączeniach rurowych W artykule przedstawiono wyniki badań doświadczalnych spawania ściegu graniowego w pozycji PJ przy użyciu nowoczesnej odmiany metody MAG-SpeedRoot. Porównano warunki i wyniki spawania ściegu graniowego MAG-SpeedRoot z metodami stosowanymi tradycyjnie. Metoda MAG-SpeedRoot została opracowana przez firmę Lorch (niemcy) do spawania ściegu graniowego blach w pozycji PG. Celem prezentowanej pracy było wdrożenie w firmie JT Zakład Budowy Gazociągów w Warszawie technologii spawania ściegów graniowych spoin czołowych rurociągów stalowych metodą MAG w odmianie SpeedRoot. W efekcie, pierwszy raz w historii prezentowana technologia została uznana przez jednostkę notyfikowaną UDT.

The paper presents the results of experimental studies of the properties of modern welding power source made in technology MICOR. It differs from the conventional inverter that on the primary side there are two inverters and two high frequency electric transformers combined in one electrical system. This paper also presents the external characteristics of the power source an selected properties of welds. in polish Nowe funkcje zasilaczy inwertorowych zbudowanych techniką MICOR do metody MMA W artykule przedstawiono wyniki badań doświadczalnych właściwości użytkowych nowoczesnego spawalniczego źródła inwertorowego wykonanego w technice MICOR. Różni się ono od klasycznego zasilacza z przemianą częstotliwości tym, że po stronie pierwotnej zastosowano dwa falowniki oraz dwa transformatory wysokiej częstotliwości połączone w jeden układ elektryczny. Zaprezentowano zewnętrzne charakterystyki statyczne i dynamiczne oraz wybrane właściwości spoin.

W pracy przedstawiono potencjalne ograniczenia stosowania materiałów na instalacje energetyczne. Zawarto zestawienie możliwych konstrukcyjnych i technologicznych zabiegów okołospawalniczych mogących poprawić właściwości złączy spawanych. Wskazano, że jest to szczególnie ważne w nowoczesnych materiałach konstrukcyjnych, do których należą stopy o wysokiej zawartości niklu i stale energetyczne. Wymieniono też przyczyny, dla których stosowanie tych zabiegów może być konieczne. Methods for improvement of weld joints operational properties Abstract The paper presents a number of potential limitations in the application of materials for power facilities. The list of possible structural and technological operations related to welding processes is presented. These operations can improve different properties of weld joints. It is shown that the operations are particularly important in case of modern structural materials that include nickel rich alloys and steels for power engineering. The reasons that make the application of these operations necessary are also pre- sented.

The article presents the results of experimental studies of welding conditions and compared the properties of butt-welding technology using innovative low energy variant of the MAG method – SpeedRoot in the PG position with a conventional TIG welding in the PF position. Rated capacity of both welding processes, the dynamic characteristics of power sources and the macrostructure of obtained joints. in polish Ocena wydajności spawania niskoenergetycznego procesu speedRoot w pozycji PG W artykule przedstawiono wyniki badań, poświęconych porównaniu warunków spawania i właściwości technologicznych spawania złączy doczołowych innowacyjną niskoenergetyczną odmianą metody MAG – SpeedRoot w pozycji PG z tradycyjnym spawaniem metodą TIG w pozycji PF. Oceniono wydajność spawania obu procesów, charakterystyki dynamiczne źródeł zasilania oraz geometrię i budowę makrostrukturalną uzyskanych spoin.