Welding Metallurgy of
01 Jan 1987-
About: The article was published on 1987-01-01 and is currently open access. It has received 991 citations till now. The article focuses on the topics: Welding.
Citations
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TL;DR: In this paper, a flow formed C-250 maraging steel tubing was welded by electron beam welded (EBW) process and subsequently age hardened, and the tensile strength was increased by 12% and the percentage elongation was remarkably increased by 92%.
Abstract: A flow formed C-250 maraging steel tubing was welded by electron beam welded (EBW) process and subsequently age hardened. Conventional EB welding with high energy input had resulted in seriously inadequate percentage elongation of the weldment. With an additional prewelding stress relief treatment and EBW with a lower energy input, the elongation of the weldment showed significant improvement after being treated with age hardening. It was found that the tensile strength was increased by 12% and the percentage elongation was remarkably increased by 92%.
6 citations
TL;DR: In this paper, the effect of preheating on the microstructure and hot crack creation in the pulsed laser welding of AA 6061 was investigated by an optical microscope and field emission electron microscopy.
Abstract: Revealing grains and very fine dendrites in a solidified weld metal of aluminum-magnesium-silicon alloys is difficult and thus, there is no evidence to validate the micro- and meso-scale physical models for hot cracks. In this research, the effect of preheating on the microstructure and hot crack creation in the pulsed laser welding of AA 6061 was investigated by an optical microscope and field emission electron microscopy. Etching was carried out in the gas phase using fresh Keller’s reagent for 600 s. The results showed that the grain size of the weld metal was proportional to the grain size of the base metal and was independent of the preheating temperature. Hot cracks passed the grain boundaries of the weld and the base metal. Lower solidification rates in the preheated samples led to coarser arm spacing; therefore, a lower cooling rate. Despite the results predicted by the micro and meso-scale models, lower cooling rates resulted in increased hot cracks. The cracks could grow in the weld metal after solidification; therefore, hot cracks were larger than predicted by the hot crack prediction models.
6 citations
TL;DR: In this article, the authors used the Modified Varestraint Transvarestrain (MVT) test to investigate the solidification cracking susceptibility of an unstabilised, a Nb-stabilised and two (Ti,+ nb) dual-Stabilised ferritic stainless steels.
Abstract: The Modified Varestraint Transvarestraint (MVT) test was used to investigate the solidification cracking susceptibility of an unstabilised, a Nb-stabilised and two (Ti + Nb) dual-stabilised ferritic stainless steels. Two different welding speeds of 6 and 3 mm/s using autogenous gas tungsten arc welding were employed. At the welding speed of 6 mm/s, the high-content (Ti + Nb) steel was resistant and the Nb-stabilised steel was marginally susceptible to solidification cracking. At the welding speed of 3 mm/s, the Nb and the high (Ti + Nb) steels were found to be marginally susceptible to solidification cracking while the unstabilised and low-content (Ti + Nb) grades were resistant to solidification cracking. The weld metal microstructures transverse to the welding direction revealed columnar grains in all the samples for both welding speeds. The ferritic stainless steels were generally resistant to solidification cracking, except the Nb-stabilised steel, which was marginally susceptible to solidification cracking.
5 citations
Cites background or methods from "Welding Metallurgy of"
...Teardrop pool shapes are found at high welding speeds, which result in columnar grains [1, 2]....
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...Solidification cracking mostly occurs at the centreline of the weld [1, 4, 5]....
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...In this method, the specimen is bent with a defined bending rate around a die as the weld is being made [1, 4, 7, 9, 10]....
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TL;DR: In this paper, a development of the equipment and an evaluation of the process of powder fed transferred arc plasma welding (PTA powder) with an emphasis on its utilization in coating metallic surfaces out of a flat position was presented.
Abstract: This work sets out a development of the equipment and an evaluation of the process of powder fed transferred arc plasma welding (PTA powder) with an emphasis on its utilization in coating metallic surfaces out of a flat position. After analysing the possibility of using the process in refurbishing hydraulic turbines eroded by cavitation, an analysis was made of the performance of the process and of the influence of the type of current (constant direct current and pulsed direct current) on resistance to cavitation of Stellite 6 alloy in accordance with ASTM standard G-32/92, by the indirect method. From the Stellite 6 alloy coatings deposited by the PTA process – powder using constant direct current and pulsed direct current, no significant difference was observed in the resistance to cavitation. On the other hand, the resistance to cavitation of the Stellite 6 alloy coatings obtained by the PTA powder process showed a performance higher than that of the Cavitec alloy obtained with the MIG and wire fed PTA...
5 citations
TL;DR: In this paper, in-situ composite coatings of TiC-Al2O3, as well as TiB2-TiC-B4C were applied on the surface of 304 stainless steel by using combining, welding and self-combustion synthesis with different current welding.
Abstract: The purpose of this study was to improve the performance of 304 stainless steel by applying a wear-resistant coating. For this purpose, in-situ composite coatings of TiC-Al2O3, as well as TiB2-TiC-Al2O3, were applied on the surface of 304 stainless steel by using combining, welding and self-combustion synthesis with different current welding. The microstructural investigations of the coated layers showed that due to the high incoming welding temperature in all the samples, by performing the combustion synthesis reaction, significant reinforcing particles were formed on the 304 stainless steel surface. Also, in all heat inputs, cubic titanium carbide particles formed inhomogeneously on Al2O3 particles or spontaneously in the austenitic matrix of 304 stainless steel. The reinforcing of TiC and TiB2 particles formation in both 3TiO2-4Al-3C and 3TiO2-4Al-B4C layers led to an increase in surface hardness and wear resistance up to 2.5 versus the substrate. K e y w o r d s: gas tungsten arc welding (GTAW), composite, 304 stainless steel, microstructure
5 citations
Cites background from "Welding Metallurgy of"
...One of the main characteristics of this growth is the similarity of the crystalline structures and the chemical compositions of the weld metal and the base metal, which can prevent the formation of stress in the joint [21, 22]....
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References
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TL;DR: In this article, the state of the art in selective laser sintering/melting (SLS/SLM) processing of aluminium powders is reviewed from different perspectives, including powder metallurgy (P/M), pulsed electric current (PECS), and laser welding of aluminium alloys.
1,172 citations
TL;DR: In this article, the authors show that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal modulator that is able to slow down but not entirely block the dislocation motion.
557 citations
TL;DR: In this article, the fundamental understanding of structure-properties relationship in automotive steels resistance spot welds is discussed. And a brief review of friction stir spot welding, as an alternative to RSW, is also included.
Abstract: Spot welding, particularly resistance spot welding (RSW), is a critical joining process in automotive industry. The development of advanced high strength steels for applications in automotive industry is accompanied with a challenge to better understand the physical and mechanical metallurgy of these materials during RSW. The present paper critically reviews the fundamental understanding of structure–properties relationship in automotive steels resistance spot welds. The focus is on the metallurgical characteristics, hardness–microstructure correlation, interfacial to pullout failure mode transition and mechanical performance of steel resistance spot welds under quasi-static, fatigue and impact loading conditions. A brief review of friction stir spot welding, as an alternative to RSW, is also included.
369 citations
TL;DR: In this article, a unified equation to compute the energy density is proposed to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.
369 citations
TL;DR: This study attempted to predict solidification defects by DNN regression with a small dataset that contains 487 data points and found that a pre-trained and fine-tuned DNN shows better generalization performance over shallow neural network, support vector machine, and DNN trained by conventional methods.
314 citations