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.
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TL;DR: In this article, the authors examined the possibility of lessening the elemental segregation in conventional arc welding techniques and showed that steady fluid flow with crack-free welding was succeeded in all the weldments.
Abstract: Elemental segregation leads to hot fissuring in the Incoloy 20. The present investigation examines the possibility of lessening the elemental segregation in the conventional arc welding techniques. In the present investigation, Incoloy 20 plates were fused by continuous current gas tungsten arc welding (CCGTAW) and pulsed current gas tungsten arc welding (PCGTAW) with two different nickel-based filler wires (ERNiCrMo-2 and ERNiCrMo-3). The result of the macroexamination shows that steady fluid flow with crack-free welding was succeeded in all the weldments. Optical and scanning electron microscope proves the columnar and cellular structure in CCGTAW specimens and fine equiaxed dendritic structure in PCGTAW specimens. Energy-dispersive spectroscopy (EDS) and X-ray diffraction results exhibit that the weld joint produced by CCGTAW ERNiCrMo-2 shows Cr segregation that leads to the formation of M23C6 phases in the interdendritic regions, whereas ERNiCrMo-3 shows the presence of NbC instead of M23C6. The elemental segregation is suppressed when it comes to PCGTA weldments in both filler wires. Electron backscatter diffraction analysis shows that the CCGTA weldments show coarser grain structure in the heat-affected zone (HAZ). In all the cases, the formation of secondary phases affects the strength of the weld joints at HAZ. Refined microstructure obtained in the PCGTAW in both filler wires shows the marginally higher ultimate tensile strength and toughness compared to the corresponding CCGTA weldments. From the corrosion study, PCGTAW specimens exhibit higher corrosion resistance than the CCGTAW specimens for both filler wires.
2 citations
01 Jan 2019
2 citations
Cites background from "Welding Metallurgy of"
...relating the cooling rate (?̇?) and primary dendrite arm spacing for SS 316L material was applied [22, 33]:...
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...Epitaxial columnar grain morphology is the most common feature of laser DED microstructure [33]....
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TL;DR: In this paper , the effect of microstructural evolution on the mechanical properties in the intercritical heataffected zone (ICHAZ) of the quenched andtempered ultrahigh-strength steel, the simulated ICHAZ samples with different austenite transformation degrees (0, 25, 50, 75, and 100%) are prepared.
Abstract: In order to investigate the effect of microstructural evolution on the mechanical properties in the intercritical heat‐affected zone (ICHAZ) of the quenched‐and‐tempered ultrahigh‐strength steel, the simulated ICHAZ samples with different austenite transformation degrees (0%, 25%, 50%, 75%, and 100%) are prepared. These samples are named IC‐0%, IC‐25%, IC‐50%, IC‐75%, and IC‐100%, respectively. The fine‐grained fresh martensite (FM) is produced in the partial austenite transformation during cooling. The austenite in IC‐100% with the lowest C and Mn content is transformed into a mixture of FM and granular bainite (GB). The IC‐0% and the IC‐25% are softened by about 20 HV10 compared with that of the base metal. When the matrix is transformed into quasi‐polygonal ferrite (QPF), the large difference in microhardness between FM and QPF causes the instability of their interfaces, resulting in the deterioration of the impact toughness in IC‐50% and IC‐75%. However, from IC‐75% to IC‐100%, the impact toughness has been improved from 18.0 to 28.9 J. In addition to the less embrittlement of microstructure in IC‐100%, the lower microhardness difference between FM and GB is the main reason.
2 citations
TL;DR: A review of the work that has been carried out in the field of Al-Mg friction stir welding can be found in this paper , where the investigative technique is addressed by describing the joining mechanism, heat generation and the challenges encountered during AlMg unification, observed trends in phase transformation, microstructural evolution, mechanical properties, tool design, and different theories related to Intermetallic compounds (IMCs) formation.
Abstract: Abstract Friction stir welding (FSW) is a solid-state welding process used to join aluminum and magnesium alloys. Their lightweight, high specific strength, ductility, low density, and many more properties make them superior to use in different industries such as automotive, shipbuilding, aerospace, etc. Friction stir welding (FSW) of aluminum-magnesium alloys of various grades has attracted significant scientific and industrial attention because of its ability to transform a product into a high-quality joint. In FSW, the plastic flow of the material under a rotating non-consumable tool is controlled by the base metal properties such as tensile strength, hardness, etc. The weld quality in FSW is determined by various process factors such as base metal position, welding speed, rotational tool speed, etc. This paper intends to provide a review of the work that has been carried out in the field of Al-Mg friction stir welding. The investigative technique is addressed by describing the joining mechanism, heat generation and the challenges encountered during Al-Mg unification. Further, observed trends in phase transformation, microstructural evolution, mechanical properties, tool design, and different theories related to Intermetallic compounds (IMCs) formation are analyzed. Finally, this work highlights the key findings of previous research and suggests future directions for welding aluminum-magnesium alloys using FSW.
2 citations
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.
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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.
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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
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