Susceptibility of electrolytically galvanized dual-phase steel sheets to liquid metal embrittlement during resistance spot welding

2018 ◽  
Vol 62 (5) ◽  
pp. 1031-1037 ◽  
Author(s):  
Julian Frei ◽  
Michael Rethmeier
Keyword(s):  
Liquid Metal ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Dual Phase Steel ◽  
Liquid Metal Embrittlement ◽  
Dual Phase ◽  
Resistance Spot ◽  
Steel Sheets

scholarly journals Liquid Metal Embrittlement of Galvanized TRIP Steels in Resistance Spot Welding

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 787 ◽  
Author(s):  
Wook-Sang Jeon ◽  
Ashutosh Sharma ◽  
Jae Pil Jung
Keyword(s):  
Liquid Metal ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
High Strength Steels ◽  
High Strength ◽  
Liquid Metal Embrittlement ◽  
Surface Cracks ◽  
Resistance Spot ◽  
Research Activities ◽  
Microscopic Features

Liquid metal embrittlement (LME) in Zn-coated steels is a serious issue in automotive design. The risk of rising LME surface cracks in resistance spot welding (RSW) of Zn-coated high strength steels has triggered significant research activities across the globe. This paper presents a state-of-the-art review of the various phenomena and issues related to LME during RSW. Various aspects of LME surface cracks have been described in this review, focusing on the macro- and microscopic features of LME, spot weld cracks, the sensitivity of the LME cracks towards surface locations, welding conditions, and susceptibility to high strength and galvanized steels. We also focus on the effects of various processing factors, such as temperature, stress, microstructure, and the nature of the galvanized layer, related to studies with actual spot welds LME cracks. Finally, we summarize the possible mechanisms of embrittlement and the remedies for minimizing LME cracks, with suitable guidelines to suppress surface cracks during RSW.

Research on Resistance Spot Welding of DP980 Dual Phase Steel

2013 ◽  
Vol 860-863 ◽  
pp. 780-783
Author(s):  
Qiao Bo Feng ◽  
Yun Feng Zhu ◽  
He Xin Zhao
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Dual Phase Steel ◽  
Welding Current ◽  
High Resistivity ◽  
Dual Phase ◽  
Welding Joint ◽  
Resistance Spot ◽  
Electrode Force

The process parameters and quality of resistance spot welding for DP980 dual phase steel were studied through the orthogonal experiment method, and the influence of welding current, welding time and electrode force on the strength of welding joint has been discussed. The results show that the welding current has the greatest influence on the quality of welding joint for DP980 dual phase steel, and it needs relatively lower welding current for the DP980 dual phase steel as it has high resistivity, and appropriate increasing of electrode force is a feasible way to avoid the defect of shrinkage and it improves the joint strength.

scholarly journals MULTI-OBJECTIVE OPTIMIZATION OF THE RESISTANCE SPOT-WELDING PROCESS PARAMETERS FOR THE WELDING OF DUAL-PHASE STEEL DP500

2021 ◽  
Vol 55 (2) ◽  
pp. 201-206
Author(s):  
Aleksija Djuric ◽  
Dragan Milčić ◽  
Damjan Klobčar ◽  
Biljana Marković
Keyword(s):  
Automotive Industry ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Dual Phase Steel ◽  
Mechanical Characteristics ◽  
Welding Process ◽  
Dual Phase ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Resistance Spot

Resistance spot welding (RSW) is still the most used form of welding in the automotive industry, primarily for welding steel. One of the advanced steels used in the automotive industry is dual-phase steel, so it is important to properly select the welding parameter for these steels. Therefore, this paper presents multi-objective optimization in the RSW welding process of DP 500 steel. The paper considers three different mechanical characteristics i.e., the failure load (F), failure displacement (l) and weld nugget diameter (D), as all these welding characteristics play significant roles in evaluating the quality of spot welding. The results show that the welding current is the most influential parameter with respect to the mechanical characteristics. The effect of welding time on the weld quality is the least significant. The optimal parameters for welding DP 500 steel obtained in this paper are weld current 8 kA, electrode force 4.91 kN and weld time 400 ms.

Suppression of liquid metal embrittlement in resistance spot welding of TRIP steel

2019 ◽  
Vol 24 (6) ◽  
pp. 579-586 ◽  
Author(s):  
L. He ◽  
C. DiGiovanni ◽  
X. Han ◽  
C. Mehling ◽  
E. Wintjes ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Trip Steel ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Liquid Metal Embrittlement ◽  
Resistance Spot

Effect of Multiple Pulse Resistance Spot Welding Schedules on Liquid Metal Embrittlement Severity

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
E. Wintjes ◽  
C. DiGiovanni ◽  
L. He ◽  
S. Bag ◽  
F. Goodwin ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Current ◽  
Liquid Metal Embrittlement ◽  
Additional Heat ◽  
Multiple Pulse ◽  
Resistance Spot ◽  
Pulse Welding ◽  
The Impact

Zinc-coated advanced high strength steels (AHSS) used in automotive applications are susceptible to liquid metal embrittlement (LME) during resistance spot welding (RSW). This study examines the impact of multiple pulse welding schedules on LME severity in welds of TRIP1100. Two different types of pulsing methodologies have been proposed to reduce LME severity: applying a pre-pulse before the welding current to remove the zinc coating and pulsing during the welding current to manage heat generation. However, the mechanisms by which these methods affect LME severity have not been fully explored. This work showed that a welding schedule consisting of two equal length pulses resulted in the least severe LME because it reduced the amount of free zinc available for LME without creating too much tensile stress. The majority of pre-pulse welding schedules caused an increase in LME cracking due to the additional heat introduced into the weld. However, a 4 kA (low current) pre-pulse applied for 3 cy (low time) reduced LME cracking by almost 30%. The pre-pulse allowed zinc to diffuse into the coating and stabilize the zinc, without introducing too much additional heat into the weld. These results indicate that multiple pulse welding schedules may be successfully used to reduce LME cracking, although the mechanisms by which they impact LME are more complicated than previously thought.

Effect of Electrode Force on Expulsion in Resistance Spot Welding with Initial Gap

2011 ◽  
Vol 675-677 ◽  
pp. 795-798 ◽  
Author(s):  
Jie Shen ◽  
Yan Song Zhang ◽  
Xin Min Lai
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Sheet Thickness ◽  
Carbon Steels ◽  
Dual Phase ◽  
Low Carbon ◽  
Resistance Spot ◽  
Steel Sheets ◽  
Electrode Force ◽  
Joint Quality

Compared with the conventional low carbon steels, the expulsion is more prone to occur in resistance spot welding (RSW) of dual phase (DP) steels. Especially when the initial gap exists between the steel sheets, the weld expulsion would reduce the weld quality of the joint. It is important to decrease or inhibit the occurrence of the weld expulsion in auto-body assembly line in order to guarantee the joint quality. In this study, the experiments of RSW with different initial gaps have been done to study the effect of the electrode force on the expulsion using different thicknesses of dual phase steels. The results show that the increment of the electrode fore would enable to decrease the occurrence of expulsion with the increase of the sheet thickness and gap spacing in resistance spot welding of DP steel sheets.

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