Welding Metallurgy of

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Welding Metallurgy of

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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Journal Article•DOI•

A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing, microstructure, and properties

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E. O. Olakanmi¹, E. O. Olakanmi², Robert F. Cochrane¹, Kenneth Dalgarno³•Institutions (3)

University of Leeds¹, Federal University of Technology Minna², Newcastle University³

01 Oct 2015-Progress in Materials Science

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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1,172 citations

Cites background from "Welding Metallurgy of"

...(......................................................3/)(16 33* VSL GSG ∆=∆ θπγ According to Kou [144] and Savage [145], growth of the solid in fusion welding is perceived as being initiated by epitaxial growth from the substrate and proceeds by competitive growth toward the center line of the weld....
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...100 the predominant mechanism of solidification in fusion welding is the competitive growth in the weld fusion zone, Kou [144] identified and discussed the details of other mechanisms such as dendrite fragmentation, grain detachment, heterogeneous nucleation and surface nucl eatio that may tend can interrupt and/or dominate the solidification structure in fusion welding....
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...According to Kou [144] and Savage [145], growth of the solid in fusion welding is...
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...Whereas, the predominant mechanism of solidification in fusion welding is the competitive growth in the weld fusion zone, Kou [144] identified and discussed the details of other mechanisms such as dendrite fragmentation, grain detachment, heterogeneous nucleation and surface nucleatio that may tend can interrupt and/or dominate the solidification structure in fusion welding....
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Journal Article•DOI•

Dislocation network in additive manufactured steel breaks strength–ductility trade-off

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Leifeng Liu¹, Qingqing Ding², Yuan Zhong¹, Ji Zou³, Jing Wu³, Yu-Lung Chiu³, Jixue Li², Ze Zhang², Qian Yu², Zhijian Shen¹ - Show less +6 more•Institutions (3)

Stockholm University¹, Zhejiang University², University of Birmingham³

06 Dec 2017-Materials Today

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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557 citations

Journal Article•DOI•

Critical review of automotive steels spot welding: process, structure and properties

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Majid Pouranvari¹, S. P. H. Marashi²•Institutions (2)

Islamic Azad University¹, Amirkabir University of Technology²

18 Nov 2013-Science and Technology of Welding and Joining

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.

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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.

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369 citations

Cites background from "Welding Metallurgy of"

...Despite the fact that Schaeffler diagram predicts two phases (austenite plus ferrite) in the FZ of AISI 304 weld nugget microstructure, under rapid solidification conditions such as laser beam welding, a shift in solidification mode may occur.(90) It is generally believed that the change in solidification mode can often result in a fully austenitic microstructure compared to the two phase (ferrite plus austenite) microstructure that is commonly found after primary ferrite solidification....
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...In coarse grained region, which is beside the FZ, both high cooling rate and large austenite grain size coupled with the formation of the carbon rich austenite promote the formation of the martensite.(90) Figure 15 shows the microstructure gradient in TRIP780 RSW....
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...The HAZ in carbon steel weldments can be divided into three distinct subregions: (i) upper critical HAZ (UCHAZ): This region experiences peak temperatures above Ac3 transforming BM microstructure into austenite.(90) Depending on the peak temperature the supercritical HAZ can be divided to the following zones: coarse grained HAZ (CGHAZ) and fine grained HAZ....
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...It is generally believed that the change in solidification mode can often result in a fully austenitic microstructure compared to the two phase (ferrite plus austenite) microstructure that is commonly found after primary ferrite solidification.(90,95,96) Although the change in solidification mode of stainless steel in RSW has not been studied yet, very high cooling rate in RSW process can explain the formation of a fully austenitic weld nugget, as it is the case for laser beam welding....
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...If this temperature is above Mf, there can be untransformed austenite left in the FZ and it can redecompose to untempered martensite upon cooling to room temperature after tempering.(90) For a particular tempering time and tempering current, there is a minimum cooling time to achieve PF mode....
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Journal Article•DOI•

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

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João Pedro Oliveira¹, Telmo G. Santos¹, Rosa Maria Mendes Miranda¹•Institutions (1)

University of Lisbon¹

01 Jan 2020-Progress in Materials Science

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.

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369 citations

Journal Article•DOI•

Using deep neural network with small dataset to predict material defects

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Shuo Feng¹, Huiyu Zhou¹, Hongbiao Dong¹•Institutions (1)

University of Leicester¹

15 Jan 2019-Materials & Design

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.

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314 citations

Cites background from "Welding Metallurgy of"

...Solidification crack is one of the most serious defects which occurs widely in welding [27,28], casting [29–31] and additive manufacturing (AM) [32,33], which occurs at the last stage of solidification when liquid films exist between dendrites boundaries where local strains cannot be accommodated by liquid feeding and solid deformation....
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References

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Open Access

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Journal Article•DOI•

Influence of variation of energy per unit length on mechanical-technological properties of ultra-high-strength steel 22MnB5 in the laser beam welding process

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Uwe Reisgen, Simon Olschok, Benjamin Gerhards, Fatma Akyel

27 Mar 2019-Materials Testing-Materials and Components Technology and Application

TL;DR: In this article, a laser beam butt welded ultra-high strength steel 22MnB5 with 1.5 mm thickness was used under varied welding parameters such as focal diameter, welding speed and beam power.

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Abstract: Ultra-high strength steel 22MnB5 with 1.5 mm thickness was laser beam butt welded under varied welding parameters such as focal diameter, welding speed and beam power. The ultra-high stren...

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1 citations

The Quantitative Microstructural Characterization of Multipass TIG Ultra Low Carbon Bainitic Steel Weldments and Correlation with Mechanical Properties

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Daniel E. Butler

01 Sep 1993

TL;DR: In this paper, the embrittlement of ULCB/ULCB multipass TIG weldments was investigated, and it was shown that the weldments appeared to be the result of microscopic transgranular cracking, and the type, size, number and distribution of the nonmetallic inclusions did not appear to be a factor in the toughness of the weldment.

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Abstract: : The U.S. Navy has maintained a continuous research, development and certification program in ULCB steels as a possible replacement for the HY and HSLA steels currently being used in ship construction. The overall aim of this program is to develop a high strength steel with improved weldability. Improved weldability could eliminate the requirement of preheating, (a necessary and costly step required to prevent weld metal cracking in HY steels). The strength of ULCB steel weldments can be correlated to the weld metals composition in a simple manner, however the toughness of the weldment seems to fluctuate in complex manner depending on the weld metal composition, weld power, and possibly the non-metallic inclusion size, type, number and distribution. This study attempted to correlate the embrittlement of ULCB/ULCB multipass TIG weldments to the given microstructure and to the type, size, number and distribution of the nonmetallic inclusions within the weldment. This work led to the following conclusions; (A) The embrittlement of ULCB weldments appeared to be the result of microscopic transgranular cracking, (B) There exists a need to design a process which can manufacture reproducible multipass weldments to facilitate testing, and (C) the type, size, number and distribution of the nonmetallic inclusions did not appear to be a factor in the toughness of the weldments investigated. Ultra low carbon bainitc steel.

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1 citations

Dissertation•

Fatigue Behaviour of Miniature Specimens Produced by Additive Manufacturing

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João Luís Alves Prata

17 Sep 2019

TL;DR: In this paper, four point bending fatigue tests were performed under in four different conditions aiming to derive the S-N curves for each series of specimens, and four different batches of 12 specimens are proposed: two of them produced by conventional manufacturing (CM), and two others produced by AM.

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Abstract: The main goal of this dissertation is to study the fatigue behaviour of 18Ni300 maraging steels, produced either by conventional manufacturing processes and by a specific additive manufacturing process, the Selective Laser Melting (SLM), (Laser Powder Bed Fusion). In order to perform a fatigue characterisation of this material, four point bending fatigue tests were performed under in four different conditions aiming to derive the S-N curves for each series of specimens. Four different batches of 12 specimens are proposed: two of them produced by conventional manufacturing (CM), and the two others produced by AM. For the CM specimens, one batch was tested in the as-delivered condition, after machining, and the other one after a heat treatment (solution annealing and ageing). The latest presents better mechanical properties, such as the ultimate tensile strength and hardness. The objective is to evaluate the influence of the heat treatment on the fatigue behaviour of the specimens. For the AM specimens, in one of the batches, the notch was produced during the SLM process and was in the as-built condition (B series), while the other series the notch was machined after the SLM process (A series). The goal is to analyse the influence of the surface roughness on the notch area on the fatigue behaviour, since the B specimens series presents a much worse surface quality than the A ones. A metalographic analysis of the materials was carried out through microstructural observations in order to evaluate porosity and defects present on the samples. Additionally, hardness and surface roughness measurements were performed. Miniature specimens with the geometry proposed in the literature were adopted for this study. Since the fatigue testing machine available for this study was not adapted for these specimens, due to their small dimensions, a gripping mechanism was proposed and validated through FEM analysis. Furthermore, the machine was also transformed in order to perform four point bending tests instead of three point bending. FEM simulations were carried out using Abaqus, firstly to validate the gripping mechanism and then to establish comparisons between the experimental values and the numerical ones. In addition, the numerical simulations allowed to estimate the stress values around the notch which is crucial to derive the S-N curves. With the purpose of evaluating the influence of the surface roughness on the fatigue behaviour of parts, several measured surface profiles were introduced on the notch surface on Abaqus® software, and numerical stresses were obtained. The CM specimens presented a better fatigue behaviour than the AM specimens. On the AM specimens, the A specimens (machined) presented a better fatigue behaviour than the B specimens (as-built). The numeric model revealed to be too rigid, justifying the high values of stresses and reaction forces obtained.

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1 citations

Journal Article•DOI•

Effect of Heat Treatments on Microstructure and Mechanical Properties of Low Carbon Steel Pipes Welded by Induction Process

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Zakaria Boumerzoug¹, Lakhdar Lakhdari²•Institutions (2)

University of Biskra¹, University of Adrar²

01 Feb 2014-Advanced Materials Research

TL;DR: In this article, the effect of isothermal heat treatments on microstructure evolution and mechanical properties after welding by induction of A37 pipeline steel have been studied by scanning electron microscopy, hardness measurements, and tensile tests.

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Abstract: In this work, the effect of isothermal heat treatments on microstructure evolution and mechanical properties after welding by induction of A37 pipeline steel have been studied by scanning electron microscopy, hardness measurements, and tensile tests Microstructural evolution in welded joint was identified after isothermal annealing from 200 until 900 °C

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1 citations

Journal Article•DOI•

Corrosion Behavior of Weathering Steel Q450NQR1 and Welded Metal using Flux-Cored Wire in 0.01 mol/L NaHSO3 Solution

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Minghua Zhang

01 Aug 2020-International Journal of Electrochemical Science

TL;DR: In this paper, the microstructure of weld metal using flux-cored wire is mainly consisted of fine acicular ferrite and granular bainite, with some side plate ferrites and polygonal ferrite.

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1 citations