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I. M. Richardson - One of the best experts on this subject based on the ideXlab platform.
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Keyhole behaviour during laser welding of zinc-coated steel
Journal of Physics D: Applied Physics, 2011Co-Authors: Y Pan, I. M. RichardsonAbstract:The production of consistent, high quality laser welds on zinc coated steels for the automotive industry remains a challenge. A simple Overlap Joint geometry is desirable in these applications but has been shown to be extremely detrimental to laser welding because the zinc vapour formed at the interface between the two sheets expands into the keyhole and disrupts fluid flow in the melt pool, which often leads to metal ejection. In the present work, laser welding on sheets with various coating thicknesses has been performed and it is observed that the sheets with thick coatings (~ 20 µm) show surprisingly good weldability. High speed video camera visualizations of the keyhole provide insight into the keyhole dynamics during the process. It appears that the dynamic pressure of zinc vapour can effectively elongate the keyhole and the process can reach a stable state when an elongated keyhole is continuously present. A simple analytical model has been developed to describe the influence of zinc vapour on keyhole elongation.
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Influence of the Hardening Model on the Predicted Welding Distortion of DP600 Lap Joints
Materials Science Forum, 2010Co-Authors: T Schenk, Gerd Esser, I. M. Richardson, Marie KraskaAbstract:The accurate prediction of welding distortion is an important requirement for the industry in order to allow the definition of robust process parameters without the need to perform expensive experiments. Many models have been developed in the past decades in order to improve prediction. Assumptions are made to make the models tractable; however, the consequences are rarely discussed. One example for such an assumption is the strain hardening model, which is often a choice between either kinematic or isotropic hardening. This paper presents the results of tensile tests for DP600 performed from room temperature up to one thousand degrees and for different strain-rates. In order to employ a mixed isotropic-kinematic hardening model, the fractions of each hardening contribution have been determined by means of bend testing. The welding distortion of a DP600 Overlap Joint has been simulated and it is shown that such a mixed-hardening model results in more accurate and reliable results.
S.v. Kuryntsev - One of the best experts on this subject based on the ideXlab platform.
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Microstructure, mechanical and electrical properties of laser-welded Overlap Joint of CP Ti and AA2024
Optics and Lasers in Engineering, 2019Co-Authors: S.v. KuryntsevAbstract:Abstract The study results of an Overlap welded Joint of Commercially Pure Titanium Grade 4 (CP Ti) and Aluminum-Copper Alloy 2XXX series (AA2024) obtained by laser welding without defects in the form of pores and cracks are presented. A microstructure using optical and scanning electron microscopes, a phase composition using X-Ray Diffraction, an electrical resistivity of welded Joints were studied. It was found that at tensile shear strength (TSS) testing, failure occurs not only in the brittle intermetallic zone of the welded Joint but also in the columnar heat affected zone (HAZ) of aluminum. A 1% of titanium does not have time to diffuse from the HAZ of aluminum at a higher welding speed (150 mm/s), whereas, at a speed of 20% less titanium is not observed in the HAZ of aluminum. The tensile shear strength of samples welded on the titanium side is in the range of 80–120 MPa, depending on the rate of input energy.
Y Pan - One of the best experts on this subject based on the ideXlab platform.
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Keyhole behaviour during laser welding of zinc-coated steel
Journal of Physics D: Applied Physics, 2011Co-Authors: Y Pan, I. M. RichardsonAbstract:The production of consistent, high quality laser welds on zinc coated steels for the automotive industry remains a challenge. A simple Overlap Joint geometry is desirable in these applications but has been shown to be extremely detrimental to laser welding because the zinc vapour formed at the interface between the two sheets expands into the keyhole and disrupts fluid flow in the melt pool, which often leads to metal ejection. In the present work, laser welding on sheets with various coating thicknesses has been performed and it is observed that the sheets with thick coatings (~ 20 µm) show surprisingly good weldability. High speed video camera visualizations of the keyhole provide insight into the keyhole dynamics during the process. It appears that the dynamic pressure of zinc vapour can effectively elongate the keyhole and the process can reach a stable state when an elongated keyhole is continuously present. A simple analytical model has been developed to describe the influence of zinc vapour on keyhole elongation.
Salim Aslanlar - One of the best experts on this subject based on the ideXlab platform.
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influence of current intensity and heat input in metal inert gas brazed Joints of trip 800 thin zinc coated steel plates
Materials & Design, 2013Co-Authors: Faruk Varol, E Ferik, Ugur Ozsarac, Salim AslanlarAbstract:Abstract In this study, TRIP 800 (transformation induced plasticity) steel plates having 1.5 mm thickness were joined by copper-based (CuAl8) wire in gas metal arc brazing technique. Specimens were prepared in two different joining forms as butt Joint and Overlap Joint. Both types of brazing operations were done with eight different arc voltages and weld currents as 45, 50, 55, 60, 65, 70, 75 and 80 A. S Cu 6100(CuAl8) wire composed largely of copper serves as the filler metal were used. Having accomplished the brazing operations; tensile properties of Joints were detected, and micro and macro-structures of Joints were investigated in order to see the joinability of TRIP 800 steel by gas metal arc brazing technique.
J C Huang - One of the best experts on this subject based on the ideXlab platform.
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lap shear and t peel strength of Overlap Joints of superplastic 8090 ai li sheets bonded by electron beam and laser beam welding
Materials Science and Technology, 1997Co-Authors: S C Chen, J C HuangAbstract:Abstract The Overlap Joint characteristics of superplastic 8090 aluminium alloy sheets made by electron beam welding (EBW) under vacuum and laser beam welding (LBW) using an argon gas protective atmosphere have been studied. The heat input applied was controlled between 6.7 and 13.3 kJ m-1, for EBW and 36.9 and 109.1 kJ m-1 for LBW, respectively. Grain structure and porosity dispersion were different for each Joint, depending on welding method, welding parameters, and the position of the bond line interface within the fusion zone. Lap shear strengths of as welded (A W) and A W + T6 specimens were scattered within 110–180 MN m-2 and 170-220 MN m-2, respectively, with a Joint efficiency of 70–85%. T peel strengths were 30–55 N mm-1 for the AW samples and 20–75 N mm1 for the AW + T6 Joints. These values are similar to those reported for diffusion bonded Joints. In most cases, EBW under vacuum yielded better results in terms of fewer and smaller pores with higher depth/width ratios of the fusion zone. The dep...
