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The compatibility problems become main concern in the utilization of biodiesel especially regarding to degradation and corrosion. The present study is conducted to describe the corrosion behaviour that occurs in steel tanks after contact with palm-based biodiesel for a period of 7 months. The storage tank used is respectively made of galvanised steel (GS), carbon steel (CS) and stainless steel (SS). It is performed in vertical cylinders with a floating-roof model. In every 30 days of storage time, the profile changes in the wall, roof and base surface of each tank were observed. The oil fuel properties were monitored in the parameter of viscosity, acid numbers, water content and oil colour. The topographic profiles on the surface of the walls and bottom of each tank wetted by biodiesel were examined over three zones inside the tanks using an endoscope imager. The main results of this study indicate that the tank steel with different protective layers exhibits different types of corrosion. The corrosion was localized in SS tanks but generalized in GS and CS tanks. The oil contamination in SS tanks was relatively lower than that in CS and GS tanks. The type of corrosion performed differently in different zones on the inside of the tank. The potential for leaks is greater at the base than on the walls and roof of the storage tank.

In this research work, samples of low carbon steel AISI 1017 subjected to shot peening process for 15 minutes. These samples were cleaned and coated with epoxy. The coating process were carried out with epoxy, epoxy mixed with alumina powder, epoxy mixed with silicon carbide powder and the last case, the steel coated with epoxy mixed with alumina and silicon carbide powders. Results showed that the corrosion resistance of steel coated with epoxy and alumina were better as compared with other samples .

In this present research, optimization of spot-welding process parameters was done on the low carbon steel grade (JSC 590RN) using Taguchi L18 methodology. The main process parameters of spot welding namely electrode diameter (d), electrode force (F), welding current (I) and weld time (t) are taken to determine the quality characteristics of the joint. Heat affected Zone (HAZ), Nugget diameter (N-D) and tensile strength were taken as a quality characteristic for the improvement. For experimental trials, Taguchi L18 was selected. The GRA technique was used to observe the level of importance of process factors on spot welding. ANOVA results show that amid all control factors, welding current (39.19%) is the highest participating followed by weld time (23.81%). In this experiment, the confirmation result shows that it is possible to increases the weld quality up to 12.0081%.

This study addresses the influence of material variations on the grindability of crankshaft steel. Most previous studies on the effect of material microstructure on grindability involve comparisons of significantly different steel grades. This study, in contrast, is focused on batch-to-batch grindability variations for one steel grade, a scenario frequently occurring in industry where batches from different steel makers are fed into a production line. For this purpose, a batch made of recycled steel and a batch made of ore-based steel were compared with regards to microstructure and grindability under identical grinding and dressing conditions. Although both batches met the same material specifications, microstructural variations were identified in terms of grain size and micro-constituents (inclusions, carbonitrides). While specific grinding energy, residual stress and full-width at half-maximum profiles of ground surfaces were the same for both batches, the recycled batch showed different and unfavorable variation in wheel wear and Barkhausen noise (BN) response. Larger fractions of oxide inclusions and larger grain sizes (affected by carbonitrides) were present in the recycled batch, which were the likely reasons for the differences in wheel wear and BN response, respectively. These findings may aid grindability improvement by steel-grade adjustments, e.g. modification of the distribution and type of inclusions and/or amount of elements forming carbonitrides. Furthermore, the results highlight the importance of understanding and controlling material microstructure, as existing in-line quality by BN control may not always be able to correctly indicate surface integrity, which could lead to misinterpretations (e.g. false part-rejection on the assumption of grinding burn).

Cathodic protection is a well-known technique to control corrosion of buried structures, even in the presence of a grounding system. In fact, without cathodic protection, the grounded carbon steel ...

The AISI 904L steel is a superaustenitic stainless steel, which presents a good combination of properties like high strength, weldability, and good corrosion resistance. Despite its wide use in several industrial segments, the literature reporting the performance of claddings deposited with this alloy to improve the corrosion performance of equipment is limited. Based on this scenario, this work evaluates the microstructure and corrosion properties of the AISI 904L steel weld cladding obtained by the electroslag welding (ESW) deposited on a carbon steel ASTM A516 Grade 70. Single layer cladding was deposited on 50 × 400 × 400 mm steel plates with average welding energy of 11.7 kJ/mm to obtain the minimum thickness required. After welding, metallographic examination and corrosion tests were performed on samples removed at 1 and 3 mm parallel to the fusion line. Metallographic characterization was performed by optical and scanning electron microscopy. Cyclic polarization tests in 3.5% NaCl solution were performed at the same positions as the metallographic examinations. The results showed that the austenitic microstructure presenting a low volume fraction of secondary phases provided suitable corrosion results for all conditions studied. It evidences that single layer weld overlays obtained with the AISI 904L steel deposited by the ESW process may be considered an adequate alternative for overlay welding with reduced thicknesses because good results were observed at only 1.0 mm from the fusion line, and this could represent a significant cost reduction.

Previous researches have carried out studying the corrosion behavior of steels, the most frequently used steels are medium carbon steel, alloy steel, and stainless steel. This is due to their wide range of applications. So, corrosion behavior is necessary to be analyzed for every steel type because of its wide function. This study was aimed to analyze the corrosion rate, macrostructure, and the XRD results of the AISI 1045, AISI 4140, and SS 304 which represent every steel type. Then, the steels were exposed to the 0.5M H2SO4 solution with various corrosion times. The variation of the corrosion time was 48, 96, and 144 hours. The results of this study revealed that AISI 1045 showed the highest corrosion rate with the value of 183.7 mpy at 144 hours of the time variation. All specimens obtained an increase in the corrosion rate with the increase in the corrosion time. Furthermore, for the macrostructure results, AISI 1045 and AISI 4140 gave obvious rust on the surface of the specimens for all time variation. The corrosion spots appear in the time variation of 96 and 144 hours for SS 304 specimens. XRD analysis confirmed the presence of metal oxides as corrosion products.

A novel desulphurization technology has been put forward using a dispersed in-situ phases induced by an explosive reaction of a composite ball. A composite ball with this function has been designed...

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

A 300-metric ton converter in a steel plant in China was studied. The influence of factors such as slag composition and temperature in the smelting process on the dephosphorization effect was statistically analyzed. The dephosphorization ability of slag increased firstly and then decreased with the increase of temperature, basicity and FeO content. Low-temperature, high-basicity and high-oxidizing slag are thermodynamically beneficial to promote the dephosphorization reaction, but the basicity is higher than 4.0, and the temperature is higher than 1640 °C are not conducive to the slag to obtain better fluidity. At the same time, too high FeO content will increase the activity coefficient of P2O5, thereby increasing its activity, which is not conducive to the progress of the dephosphorization reaction. As the end point content of carbon decreases, the oxygen content increases and the phosphorus content decreases. A very low carbon content is not conducive to metal yield and temperature control.

The continuous electrolytic copper plating process traditionally includes degreasing and acid baths before copper plating baths. These baths add difficult-to-control parameters to the process. Besides they contain various alkaline chemicals and acids that are harmful to the environment. The plasma surface treatment is a controllable alternative surface cleaning method which is used in various fields. Also it can be used for surface activation to improve plating performance. Another important aspect of the plasma process is its environmental friendliness. It has a high potential to make plating preparation stages environmentally friendly and efficient. In this study a plasma surface treatment system is attached on a traditional copper plating line which is used for cold rolled low carbon steel sheets. It was determined that plasma surface treatment had a positive effect on the quality of copper plating.

This paper investigates the feasibility of producing hard structures capable of wear resistance by depositing a hardfacing flux-cored wire while using arc directed energy deposition (DED-Arc) as process. The present paper discloses the compatibility of a metal hardfacing flux-cored wire with this technology by deposition of single walls and block fabrication. The deposition of walls and blocks was made using different parameters and deposition strategies, in order to avoid solidification cracking associated with the precipitation of chromium carbides. Macro and microstructural analyses, as well as hardness tests, were carried out to validate the use of this wire with DED-Arc. The use of a grinder for slag removal was also investigated. Withal, the deposition of a 40-layer wall and blocks indicated that a hardfacing flux-cored wire can be used to produce a near net shape part by additive manufacturing. Additionally, gradient properties of additively manufactured metal parts can be achieved by depositing layers of materials with different characteristics and, with DED-Arc, this can be done through the use of different types of metal wire. Thus, studies on the possibility of constructing a bi-metallic part, by DED-Arc, using a low carbon steel (ER70S-6) and the same hardfacing-cored wire were developed, focusing on crack minimization procedures, such as the application of pre-heating. Assessment of metallurgical transformations and mechanical properties were investigated to assure that the material properties were kept. A final multi-metal part was produced with DED-Arc.

The present study revealed that the martensitic stainless steel AISI 420 and mild/low carbon steel AISI 1018 could be successfully joined by using friction welding technique at different parameters such as friction time and friction pressure. Macro and microstructural characterizations of welded materials were performed by optical microscope (OM), X-ray diffractometer (XRD) and scanning electron microscope with energy-dispersive X-ray spectroscop. Also, tensile and microhardness tests were performed to determine the mechanical properties. The most interesting aspect of this study is the determination of ferrite, retained austenite and chromium phases in the weld zone by XRD analysis, and in tensile tests, the fracture occurred outside the weld zone at a maximum tensile strength of 527 MPa. Moreover, the diffusions of phases such as chromium and carbon were observed in the weld zone, and the microhardness measured in the weld zone was found to be higher with 591 HV than the one measured in the base materials.

Microbiologically influenced corrosion (MIC) often occurs at the bottom of shale gas-gathering pipelines. Under the condition of pipe flow, the synergistic behavior of SRB corrosion and other factors is not clear. Based on the home-made multiphase flow corrosion loop, the biofilm formation and corrosion of sulfate-reducing bacteria on the surface of a shale gas pipeline steel L360N at different liquid flow rates are studied. At low flow rates such as 0.2 m/s and 0.5 m/s, the SRB biofilm gradually thickens. When the flow rate is 1.0 m/s ~ 1.5 m/s, the existing SRB biofilm is stripped. With the increase in velocity, the average and local corrosion rates first increase and then decrease. The synergistic corrosion of MIC and flow rate in the pipe will change with the increase in flow rate. SRB dominated the corrosion of L360N steel at low flow rate. At high velocity, the corrosion of L360N steel is accelerated by flow erosion after the biofilm is stripped. This study clarifies the corrosion behavior of the interaction between SRB and flow rate, and this understanding has rarely been reported in the past literature and can provide a basis for corrosion protection of shale gas field.

Wire arc additive manufacturing (WAAM), a welding-based additive manufacturing (AM) method, is a hot topic of research since it allows for the cost-effective fabrication of large-scale metal components at relatively high deposition rates. In the present study, the cylindrical component of low carbon steel (ER70S-6) was built by WAAM technique, using a GMAW torch that was translated by an automated three-axis motion system using a rotation table. The mechanical properties of the component were evaluated by extracting tensile, impact toughness and hardness specimens from the two regions of the building up (vertical) direction. It is found that the tensile properties of the built material exhibited anisotropic characteristics. The yield strength and ultimate tensile strength varied from 333 to 350 MPa and from 429 to 446 MPa, respectively, (less than 5 % variation).

The objective of this paper is to study the surface texture behavior of low and medium-carbon steels machine elements in acidic environment using Abbott Firestone curve depending upon MATLAB software. The chemical composition of low-carbon steel is 0.16C-0.27Si-1.47Mn-0.02Al while medium-carbon steel is 0.49C-0.30Si-0.91Mn-0.03Al. They were hot-rolled at 1200°C for 30 min followed by air cooling. Two different heat treatment processes were applied on the hot-rolled samples. The first treatment was quenching after martensite finish (QAMf) and the second one was quenching and partitioning (Q&P). For 0.16C, the microstructure gives bands of ferrite and pearlite after hot-rolled steel. However, 0.49C produces coarse pearlite islands surrounded by ferrite phase. While, the microstructure after QAMf and Q&P processes contain ferrite, bainite, lath martensite, and retained austenite for 0.16C steel, and polygonal ferrite, lath martensite, and retained austenite for 0.49C steel, respectively. In low-carbon steel (0.16C), after hot-rolling, steel suffers from low exploitation zone (44%) of surface texture. However, after QAMf, low-carbon steel (0.16C) gives lower surface texture (36%). In addition, hot-rolled steel (0.16C) produces 40% voids zone while after QAMf, voids zone increases to 52% of surface texture. In medium-carbon steel (0.49C), after hot-rolling, steel produces 78% exploitation zone of surface texture. Furthermore, Q&P slightly enhances surface texture (exploitation zone) to 82%. At the same time, hot-rolled and Q&P of 0.49C steels exhibit very small number of voids for surface texture (1–4%). Therefore, 0.16C steel (hot-rolled and QAMf) is highly subjected to severe failure in etchy environment. However, 0.49C steel (hot-rolled and Q&P) is highly recommended in case of moderate safety factor.

Carbon steel (CS) is the preferred base material for construction in various industries due to its low cost; however, industrial equipment failure caused by carbon steel corrosion can lead to several environmental risks and safety hazards, thus limiting its application scenarios. Enhancing the corrosion resistance of carbon steel and reducing the maintenance cost of carbon steel substrate have become a hot topic of current research. Therefore, in this study, a zinc oxide/polyaniline-titanium dioxide composite film (ZnO/PAni-TiO2) with long-lasting photogenerated cathodic protection was constructed based on the photoelectric conversion properties of TiO2. This new TiO2 composite film, which can avoid photogenerated electron–hole complexation, significantly enhanced the photoelectric conversion efficiency of TiO2, thereby decreasing the anodic corrosion current density of low carbon steel and enhancing the cathodic protection of carbon steel. Hence, it is expected to provide a new direction for the preparation of corrosion-resistant TiO2-laminated carbon steel nanofilms.

The structural-phase composition and some properties of medium-carbon steel modified surface after cathodic plasma electrolytic nitriding in a solution of ammonium chloride and ammonia have been studied. It is shown that cathodic nitriding of a steel surface is accompanied by high-temperature oxidation with the formation of oxides FeO, Fe2O3, and Fe3O4, as well as nitrogen diffusion and quenching with the formation of FeN, Fe3N, and Fe4N phases, martensite and the retained austenite. The competing effect of surface erosion by the actions of discharges and high-temperature oxidation on the morphology and roughness of the surface was revealed. It was established that the maximum microhardness of the modified layer reaches 1040 HV, and the corrosion current density of the nitrided surface decreases by a factor of 1.5–2.4.

The forming process of high-strength sheet metal alloys is in great demand, and its applications in nuclear and defense industries are much significant. In the present investigation, the A516-Gr70 carbon steel plates are deep-drawing under warm (700 °C) and cold (27 °C) conditions using 1000 Ton hydraulic press. Numbers of deep-drawing experiments are conducted in two different states to study the microstructure and hardness at ambient temperature and also to study the impact strength at sub-zero temperature for different regions of the cup. In this study, changes in the microstructure of the deep-drawing cups with having two different samples subjected to normalizing heat treatment are observed.

Purpose The purpose of this paper is to study the influence of temperature on the acceleration and simulation of indoor corrosion tests and the corrosion behavior of Q235 carbon steel. Design/methodology/approach The indoor corrosion test was carried out by continuous salt spray in a salt spray chamber. Weight loss analysis, X-ray diffraction, cannon 1500 D, scanning electron microscopy and electrochemical techniques are used to analyze the results. Findings It was found that thickness loss of Q235 carbon steel increases with higher temperature and it can reach 0.095 mm at 50°C. Compared with the Xisha exposure test, the acceleration rate can achieve 230 times. This phenomenon indicates that decreasing the experimental temperature is beneficial to the anti-corrosion of the Q235 carbon steel. It is fascinating to find that acceleration and simulation increase with temperature simultaneously, which shows that β-FeOOH promotes the corrosion rate and α-FeOOH provides high simulation. Meanwhile, electrochemical impedance spectroscopy indicates that the resistance of the rust layer improves with temperature. Practical implications Through the study, the authors found that with the increase of temperature, the acceleration and simulation of indoor corrosion test improved, corrosion products and kinetics are the same as those in outdoor exposure test, and which means that the laboratory can achieve the long-term corrosion degree of outdoor exposure in a short time, and the similarity with outdoor exposure is high. This helps to the study of marine atmospheric corrosion, and indoor accelerated corrosion tests can largely eliminate regional differences by adjusting some environmental factors, and lay a foundation for marine atmospheric corrosion. Originality/value The effects of temperature on the acceleration and simulation of indoor corrosion tests are discussed. Through laboratory experiments, the long-term service life of Q235 carbon in the Xisha marine atmosphere can be predicted effectively.

Steel (St) and aluminum (Al) have a high affinity to each other and form intermetallic compounds (IMCs) when bonded by friction stir welding (FSW). Understanding the effect of alloying elements of steel on the formation of IMCs will help to design joints in which the formation of IMCs is controlled. In this study, two kinds of steel, carbon steel (CS) and austenitic stainless steel (SS) with 3 mm thickness, were selected to be welded to aluminum by FSW under similar conditions. The effect of the rotation speed of the FSW tool was also examined in the range of 850–1300 RPM. The morphology, thickness, and composition of IMCs in the interfaces were studied by various characterization techniques. It was observed that the IMC layers in the SS/Al joints were much thinner than the ones in CS/Al joints (0.1–0.7 µm in SS/Al and 2–6 µm in CS/Al). Moreover, the thickness of IMC layer in CS/Al joints increased with increasing the rotation speed while in SS/Al joints it began to decline by exceeding a certain rotation speed. In order to explain these differences, diffusion-based equations were used to calculate the interdiffusion coefficients in both SS/Al and CS/Al couples. It was found that the interdiffusion coefficient in SS/Al was lower than CS/Al. This was attributed to the alloying elements of SS such as Ni and Cr which can diffuse to IMC layer and hinder the growth rate of IMCs. It was also observed that some form of liquation occurred in SS/Al joints at high rotation speed of FSW due to the formation of a low-melting multielement compound of Al–Fe–Cr–Ni. The decline of IMC thickness in SS/Al joints at high rotation speed was attributed to this multielement compound which was melted during FSW and reduced the nucleation rate of Al–Fe IMCs. Finally, the fracture of the specimens and the effect of IMC formation on the joint establishment were elaborated. It was concluded that the alloying elements of steel have a beneficial effect on controlling the growth of IMCs.

This study was aimed at evaluating the effects of exposure time and SO2 as one of the impurities on the corrosion behavior of steel pipeline transporting supercritical CO2 during carbon capture and...

Gravimetric and statistical analysis was utilized to assess the inhibition performance of extracts of green tea and moringa on 1070 aluminum in 0.5M H2SO4 solution. Data output showed green tea extract performed more effectively than moringa extract, and at all concentrations studied with optimal inhibition efficiency value of 95.08% compared to moringa which performed effectively at only one concentration with optimal value of 72.38%. Inhibition efficiency values for both extracts varied significantly with reference to exposure time and extract concentration. The optimal mean inhibition value for green tea and moringa extracts are 88.71% and 66.65%. However, the least standard deviation value of 6.22 was obtained for green tea extract with highest inhibition value indication stable inhibition and thermodynamic stability with reference to exposure time. Statistical data showed 90.5% of inhibition output for green tea extract and 9.52% of inhibition output for moringa extract were above 70% inhibition efficiency at margin of error of +12.6. Analysis of variance showed exposure time is the only statistically relevant variable influencing the inhibition output of green tea with statistical value of 78% while exposure time and moringa extract concentration are the both statistically relevant variables influencing the inhibition output of moringa with values of 61.02% and 24.02%.

Data analysis of the coating performance of Zn electrodeposited plain carbon steel in 0.5 M HCl solution at specific volume addition (5 ml, 10 ml and 15 ml) of onion, glycine and cassava (ON, GY and CS) distillate additives, and at plating time of 15 and 18 mins with respect to 538 h of observation time was performed. Analytical outputs showed ON distillate most effectively improved the Zn electrodeposited by 14% at 10 ml volume and plating time of 15 mins. GY and CS distillate generally improved the Zn electrodeposited at all volumes and plating time with optimal values of 42.7% and 45.7% at 15 ml and plating times of 15 and 18 mins. Generally, coating performance varied significantly with observation time, but marginally with plating time and additive volume. The standard deviation values for onion additive showed significant variation from mean values due to relative thermodynamic instability of it coating performance with respect to observation time. This contrast the output observed for GY and CS additives which signifies thermodynamic equilibrium. The proportion of coating performance data above 10% improvement for the additives are (ON, GY and CS) are 32%, 85% and 78% at margin of error of 11.8%, 9.04% and 10.42%. Analysis of variance showed ON and GY additive volume only, influenced the coating performance output of the additives at 64.56% and 74.67% while CS additive volume and observation time influenced the coating performance output of CS at values of 91.18% and 3.27%.

Application of sustainable chemical compounds for corrosion protection of carbon steels employed in H2O formed petrochemical drilling fluid environment (WPDF) is an effective alternative to toxic chemical compounds. The protection performance of calciofon (CF) and rosmarinus officinalis (RS) on low carbon steel (LST) in WPDF was studied with potentiodynamic polarization technique and optical microscopic characterization. Results output depict CF and RS performed adequately at specific inhibitor concentrations with average inhibition performance above 80% for CG and 90% for RS. CG exhibited mixed type inhibition effect compared to RS which exhibited anodic inhibition. The polarization curves obtained in the presence of both compounds showed they induce passivation of LST surface after anodic polarization before breakdown at the transpassive region from the lowest to highest concentration inhibitor concentrations due to their film forming and adsorption characteristics. This observation was corroborated from the protected steel surfaces which contrasts the non-protected control steel specimen which exhibited severe surface deterioration, corrosion pits and numerous furrows.

The research aims to study the effect of flow rate and temperature on corrosion rate of carbon steel pipe in condensate solution from geothermal power plant. The corrosion rate in this study highlighted by electrochemical measurement. Electrochemical measurement performed in two conditions i.e stagnant and dynamic conditions. There are three kinds of temperature used in this research : 30oC, 40oC, and 50oC. Modification of corrosion cell installed for dynamic condition with flow rate variations : 0.27 m/s; 0.6 m/s; 1 m/s; 1.5 m/s; and 1.9 m/s. It was found that corrosion rate boosts with temperature and fluid flow rate in condensate solution of geothermal power plant. The highest corrosion rate (38 mpy) obtained at 50oC and 1.9 m/s of flow rate.

The addition of Ni element into steel to prolong the service life of coated steel was investigated in marine atmospheric environment by laboratory simulated accelerated experiment. The scanning electron microscope and electron probe micro-analysis combined with electrochemical impedance spectroscopy were used to characterize coated steel properties and examined the anti-corrosion performance. The results showed that 3 wt.% Ni-advanced steel (3Ni steel) substrate obviously delayed the failure time of coating compared to carbon steel, therefore prolonging the service life of coating on the steel. X-ray diffraction patterns for the corrosion products under the scratched coating on 3Ni steel exhibited that FeNi2O4 and Fe2O3 occurred in the corrosion product of 3Ni steel. It was also found that Ni element enriched in the product layer through analyzing the appearance and composition of corrosion products by electron probe micro-analysis. Chloride ions were blocked out of product by the enrichment of Ni element in rust layer.

Purpose This paper aims to explore the transformation process and transformation mechanism of carbon steel under the marine environment. Design/methodology/approach In this paper, the transformation and rust layers corrosion products on 0Cu2Cr carbon steel with different cycles coupon test was investigated and deeply explored by scanning electron microscope, energy dispersive spectrometer, X-ray diffraction. Findings The results showed that the thickness of rust layers grew from 71.83 µm to 533.7 µm with increasing duration of corrosion. The initial corrosion product was γ-FeOOH, then part of the γ-FeOOH continued growing, and under the capillary action, the other part of the γ-FeOOH transformed to α-FeOOH. Originality/value To the best of the authors’ knowledge, this paper puts forward for the first time a new viewpoint of the development of corrosion products of low-carbon steel in two ways. This discovery provides a new idea for the future development of steel for marine engineering.

Carburizing is a method for obtaining a sturdy material surface. This hard surface is used for machine elements that intersect with other materials, so failure due to wear can be avoided. However, this increase in hardness has always been followed by decreased ductility. This condition certainly lowers the fatigue life of the material. For that, it is necessary to compromise between surface hardness and ductility. This study used AISI 1045 steel, which has a surface roughness of 0.4 and 4.7 μm with carburation media used, is a mixture of 80% coconut shell charcoal and 20% Barium carbonate. The sample was given the pack carburization treatment at 850°C and holding time for 3 hours, and then cooled in the open air. The samples were reheated at 850°C, holding time for 17 minutes, and then cooled with airflow at speeds of 10.34, 15.51, and 20.06 m/s for 30 minutes. This research shows that the surface of steel with a roughness of 0.4 μm has excellent performance with the hardness and corrosion level respectively 228.6 HV and 2.3586 mpy at cooling airflow rate of 20.06 m/s while the fatigue life of material occurs at the speed of airflow cooling 10.43 m/s.

The goal of this paper is an evaluation of research aimed at corrosion and mechanical resistance of the so-called duplex system applied to a steel sheet. This system consists of a metal coating applied by hot-dip galvanising, to which an acrylic, water-soluble paint is commonly applied (commonly available on the Czech market) using standard technology in an air stream. For the purposes of the corrosion resistance comparison, one set of test specimens is provided only with a hot-dip galvanised coating. The mechanical resistance of applied anti-corrosion protection was determined by means of a pull-off adhesion test (according to the ČSN EN ISO 4624 standard), as well as an indentation test (according to the ČSN EN ISO 1520 standard). The corrosion resistance tests were then conducted in a salt spray environment (according to the ČSN EN ISO 9227 standard) for the samples not damaged by mechanical tests. Based on the obtained results, in general, waterborne paints with high dry matter content, low specific gravity and high zinc phosphate content, which are applied in several thinner layers, can be recommended.

The main problem associated with high thickness carbon steel plate's narrow range or “V” groove welding in conventional welding processes is the sagging of the molten pool due to gravity, which in turn leads to defects formation and deteriorates mechanical properties. This problem could be overcome by the rotating arc gas metal arc welding (RA-GMAW) technique. This investigation aims to evaluate mechanical properties and metallurgical characteristics of high thickness IS2062 Gr-B carbon steel joints welded by RA-GMAW technique. The experimental results show that RA-GMAW joint exhibited higher (598 MPa) tensile strength, higher hardness (220 HV) at weld metal region, and lower impact toughness (137 J) than the unwelded base metal. This is due to the presence of fine acicular ferrite and widmanstatten ferrite matrix mixed with fine lamellar pearlite microstructure in the weld metal region.