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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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10 Jan 2020
TL;DR: Saeed et al. as mentioned in this paper investigated the dissimilar welding of NiTi shape memory alloy to AISI 304 austenitic stainless steel archwires and found that the obtained microstructure from the laser weld of these alloys has a dendritic and nonhomogeneous structure.
Abstract: In this research, dissimilar welding of NiTi shape memory alloy to AISI 304 austenitic stainless steel Archwires was investigated. For this purpose, common straight orthodontic archwire with rectangular cross-section and dimensions of * یکینورتکلا تسپ ،لوئسم هدنسیون : saeid@sut.ac.ir نا ا یراک و یروان و مو ع D ow nl oa de d fr om jw st i.i ut .a c. ir at 1 0: 56 IR S T o n M on da y F eb ru ar y 3r d 20 20 www.SID.ir Archive of SID يدسا دیعس ناراکمه و رشن ، ی ه روانف و مولع ي راکشوج ي ا ی ،نار لاس مجنپ هرامش ، 2 ، ناتسمز و زییاپ 1398 هحفص ، 152 141 142 (0.635 × 0.432 mm) were selected and the laser welding technique was used to connect the wires. The microstructure, chemical composition and phasesin the weld zone of the joints werestudied with Optical microscopy (OM), Scanning electron microscopy (SEM) equipped with EDS analysis system, focused X-ray diffraction (Micro-XRD).Also, the mechanical properties of the weld zone were investigated by using Vickers microhardness test. Microstructure investigation showed that the obtained microstructure from the laser weld of these alloys has a dendritic and nonhomogeneous structure. According to XRD analysis, brittle intermetallic compounds such as Fe2Ti, Cr2Ti, TiNi3, and Ti2Ni wereformed during laser welding in the weld zone. Formation of these brittle intermetallics caused increasing the hardness of the weld zoneabout 800 HV. and decreasing the mechanical properties. Also, Fe2Ti intermetallic particles mainly formed in the weld region near the NiTi fusion zone which results in stress concentration, micro-cracks formation and dropping joints mechanical properties. Therefore, a suitable modification process is required to control the chemical composition of the weld zone and improving the joint properties of dissimilar laser welded archwires of these alloys.

4 citations

Journal ArticleDOI
TL;DR: In this paper , a selective laser melted Inconel 718 alloy was investigated under in situ electrochemical hydrogen charging, and by multi-scale microstructural analysis, and it was shown that hydrogen significantly accelerates fatigue crack growth rate (FCGR), and such effect is intensified when decreasing load frequency.

4 citations

Dissertation
01 Jan 2018
TL;DR: Acknowledgement, acknowledgements, publication, and attestation of authorship are listed in the Appendix of the paper as mentioned in this paper, along with a table of content and a list of figures.
Abstract: ............................................................................................................................. I Acknowledgement .......................................................................................................... IV List of Publication ............................................................................................................ V Table of Content .............................................................................................................. VI List of Figures .............................................................................................................. VIII List of Tables ............................................................................................................. XVII Nomenclature ............................................................................................................ XVIII Attestation of Authorship .............................................................................................. XX

4 citations


Cites background from "Welding Metallurgy of"

  • ...Figure 1-32 Effect of temperature gradient G and growth rate R on the morphology and size of solidification microstructure [62]...

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  • ...39 Figure 1-32 Effect of temperature gradient G and growth rate R on the morphology and size of solidification microstructure [62] ....

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Journal ArticleDOI
TL;DR: In this article, the best welding practices to the duplex stainless steel UNS S32750 (Super Duplex) were studied, guaranteeing welded joints that showed the ideal volumetric fractions of ferrite and austenite and, consequently, the mechanical properties according to the project.
Abstract: Duplex stainless steels are characterized by their biphasic, ferritic-austenitic microstructure. The ideal volumetric fraction of these phases in duplex stainless steels, is of 50% ferrite and 50% austenite, however, this condition is difficult to be obtained when arc welding these materials. A detailed analysis of the effect of relative plate thickness in the heat flow and, consequently, in the cooling rate during welding of duplex stainless steel is of fundamental importance. The correct adjustment of the welding parameters leads to an optimum cooling rate of the joint, which guarantees a good balance of the volume fractions of ferrite and austenite, and results in acceptable mechanical properties and corrosion resistance. In this work, the best welding practices to the duplex stainless steel UNS S32750 (Super Duplex) were studied, guaranteeing welded joints that showed the ideal volumetric fractions of ferrite and austenite and, consequently, the mechanical properties according to the project. Complementary techniques of microstructural analysis were used, such as optical emission spectrometry, optical microscopy and quantitative image analysis.

4 citations


Cites background or methods from "Welding Metallurgy of"

  • ...Cooling rate equations can be used to calculate the critical cooling rate (CCR) under a given set of welding conditions and to determine the preheat temperature requirement for the plate in order to avoid the CCR [10, 11]....

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  • ...Cooling rate equations can be used to calculate the critical cooling rate (CCR) under a given set of welding conditions and to determine the preheat temperature requirement for the plate in order to avoid the CCR [10, 11]....

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  • ...Accordingly, two different empirical equations are used for calculating the cooling rate in HAZ depending upon the relative plate thickness and welding conditions [10, 11]....

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  • ...The thermal conditions in and near welds govern the resulting metallurgical structure, mechanical properties, residual stress and distortion of the welded part [10]....

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  • ...g), Ti is the temperature of interest (oC), and To is the initial plate temperature (oC) [10, 11]....

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24 Apr 2019
TL;DR: In this article, the welding thermal cycle and the microstructural and mechanical properties of welded aluminum AA6061-T6 plates were studied using a Yaskawa robot integrated with Fronius Trans Plus Synergic 4000 arc welding equipment and metal filler AA4043.
Abstract: GMAW welding of aluminum AA6061-T6 introduce changes in the mechanical properties of the heat affected zone (HAZ) by changing the microstructure obtained from heat treatment. The variation of the welding thermal cycle across the HAZ produces different mechanical properties in subzones of the HAZ. The purpose of this investigation is to investigate the variation of the microstructure and mechanical behaviour in the HAZ subzones and correlate these subzones with the welding thermal cycle. In this study, the welding thermal cycle, and the microstructural and mechanical properties of welded aluminum AA6061-T6 plates were studied. The plates were prepared and welded in two different configurations using a Yaskawa robot integrated with Fronius Trans Plus Synergic 4000 arc welding equipment and metal filler AA4043. The welding thermal cycle was obtained experimentally from different locations on the welded plates. Using SYSWELD software the heat source was adjusted using the thermal cycle obtained from the experimental work and the size of the welding pool to reproduce the welding thermal cycle. Simulation was performed to observe the heat distribution in two configurations of the welded plate. The numerical model offers an adequate approximation to the welding thermal profile measured during the welding process. The characterization of mechanical properties was obtained using a microhardness test on welding cross section and a 2D map used to illustrate the microhardness at the welding cross section. Moreover, mechanical behavior and local deformation in subzones of the heat affected zone were investigated using digital image correlation (DIC) with a micro-flat tensile test. The mechanical properties of subzones of the HAZ were correlated with the welding thermal cycle as well as with the microstructure of the HAZ that was investigated experimentally. It was observed that the welding thermal cycle controls the variation of the microstructure across the HAZ, which significantly effects the mechanical behaviour of the HAZ. The change of precipitates sequence from βʺ to βʹ and β explains these changes.

3 citations


Cites background from "Welding Metallurgy of"

  • ...8 Schematic of gas metal arc welding process, a) process overall, b) fusion area [23]...

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  • ...8 Schematic of gas metal arc welding process, a) process overall, b) fusion area [23]....

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  • ...Three key factors control the procedure for GMAW of aluminum: the availability of equipment, the welded material thicknesses, and the alloy content [23]....

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References
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Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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