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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01 Feb 2016
TL;DR: In this paper, the authors show that the heat-affected zone (HAZ) of fusion welds has proven more susceptible to SCC than the TMAZ of FSW.
Abstract: To avoid hot cracking when welding a Cu-lean, high-strength 7xxx series (Al-Zn-Mg) aluminum alloy (AA), and maintain acceptable joint strength, 5xxx series (Al-Mg) filler wires are utilized [1] [2]. However, such welded joints have shown a tendency to develop stress corrosion cracking (SCC) [3] [4] [5] [6]. SCC of these joints has typically occurred within the heat-affected zone (HAZ) directly adjacent to the fusion line (FL) [7] [8]; the thermomechanically affected zone (TMAZ) in solid-state joints of Al-Zn-Mg alloys, created by frictionstir welding (FSW), has also shown susceptibility to SCC. However, the HAZ of fusion welds have proven more susceptible to SCC than the TMAZ of FSW [6] [9].
2 citations
Cites background from "Welding Metallurgy of"
...However, such welded joints have shown a tendency to develop stress corrosion cracking (SCC) [3] [4] [5] [6]....
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TL;DR: In this paper, the effect of pulsed plasma welding on the distribution and amount of delta ferrite on a supermartensitic stainless steel (SMSS) was investigated and the microstructural characterization was performed via metallographic analyses by optical and scanning electron microscopy.
Abstract: Delta ferrite is considered an undesirable phase in the microstructure of martensitic stainless steels, given its power to influence the performance of fatigue strength, toughness and corrosion under stress. This study aimed to investigate the effect of pulsed plasma welding on the distribution and amount of delta ferrite on a supermartensitic stainless steel (SMSS). Weld beads were obtained by surface melting on a sample of SMSS alloy using conventional and pulsed current. Then, the microstructural characterization was performed, in particular of the delta ferrite via metallographic analyses by optical and scanning electron microscopy. The experiments showed that for the same heat input, the pulse current promoted the formation of delta ferrite in the form of bands along the weld bead and a significant reduction of this phase in the heat-affected zone compared to conventional welding.
2 citations
Cites methods from "Welding Metallurgy of"
...According toKou [11], when theR ratio is suddenly increased, an extra amount of solute is rejected to the liquid on the liquid–solid interface, promoting the increase of the concentration of solute in this region....
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...As regards the possibility of dissolution of delta ferrite, this is reported by Carrouge [10] and Kou [11], being identified in SMSS and austenitic AISI 309 (mixed structure of austenite and delta ferrite), respectively, which underwent reheating by subsequent steps....
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TL;DR: In this article , the effect of welding speed, oscillation amplitude and oscillation frequency on the fusion zone dimensions, flow profile, vorticity profile, cooling rate and thermal gradient during the butt welding of Al-5754 to Al-6005, with sinusoidal beam oscillation was analyzed.
Abstract: Abstract Remote Laser Welding (RLW) of Aluminium alloys has significant importance in lightweight manufacturing to decrease the weight of the body in white. It is critical to understand the physical process of transport phenomena during welding which is highly related to the mechanical performance of the joints. To investigate the underlying physics during welding and to understand the influence of beam oscillation on heat transfer, fluid flow and material mixing a transient three-dimensional Finite Element (FE) based Multiphysics model has been developed and validated from the experiments. The effect of welding speed, oscillation amplitude and oscillation frequency on the fusion zone dimensions, flow profile, vorticity profile, cooling rate and thermal gradient during the butt welding of Al-5754 to Al-6005, with sinusoidal beam oscillation, is analysed. It was found that one additional vortex is formed during beam oscillation welding due to the churning action of the oscillating beam. With the increase in oscillation amplitude, welds become wider and the depth of penetration decreases. An increase in oscillation frequency leads to an increase in the flow rate of the molten metal suggesting that the beam oscillation introduces a churning action that leads to an increase in mixing. It was highlighted that the material mixing depends on both diffusion and convection.
2 citations
TL;DR: In this article, the effects of the phenomenon of strain ageing in joints obtained by gas-shielded arc welding (gas metal arc welding, GMAW), of seamless pipes of API5L X65Q steel were investigated.
Abstract: In this work, we investigated the effects of the phenomenon of strain ageing in joints obtained by gas-shielded arc welding (gas metal arc welding, GMAW), of seamless pipes of API5L X65Q steel. Test specimens obtained from the welded joints were submitted to cold plastic strain of 3% and then aged for 1 h at 250 °C, so as to induce static ageing. For evaluating dynamic ageing, the test specimens were strained to 3% and loading was maintained for 1 h at 250 °C. The aged specimens were submitted to tensile testing and representative samples were examined in the light microscope and the scanning electron microscope. It was observed that the phenomenon altered the volume fraction of secondary constituents in the weld metal and in the HAZ, with increase in the proportion of ferrite–carbide aggregates. Regarding the mechanical properties, it was found that the phenomenon reduced the elastic ratio of the welded joints due to an increase in the ultimate strength, besides increasing the total elongation, b...
2 citations
TL;DR: In this paper, the authors studied the features of the austenite decomposition kinetics in the application of laser-hybrid welding technology, in a combination with multi-arc automatic submerged arc welding.
Abstract: A modern technology for joining materials welding is commonly used in various industries. It is a process of interaction of thermal, mechanical and metallurgical properties and behaviors. Complex phenomena, such as solidification, microstructural changes and defect formation, have a great impact on the quality of welded joints. This article presents the results of studying the features of the austenite decomposition kinetics in the application of laser-hybrid welding technology, in a combination with multi-arc automatic submerged arc welding. The cooling rates are determined, affecting the change in properties of HAZ of welded joints on pipe steel of strength class K52. Using the dilatometric method, studies were conducted and thermo-kinetic and structural diagrams were constructed. Analysis of diagrams and microstructures showed that, as a result of the impact of the laser-hybrid welding process in the area of HAZ, the decomposition of austenite occurs mainly in the martensitic zone, followed by the formation of a bainite-perlite structure, due to recrystallization from the heat generated by the facing seams.
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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