Effect of Severe Welding Conditions on Liquid Metal Embrittlement of a 3rd-Generation Advanced High-Strength Steel

Outhmane Siar,Sylvain Dancette,Thomas Dupuy,Damien Fabrègue,Yacine Benlatreche

doi:10.3390/met10091166

Abstract

The occurrence of liquid metal embrittlement (LME) during the resistance spot-welding of a zinc-coated Advanced High-Strength Steel (TRIP-aided AHSS) is investigated in this work. Welds are generated using controlled degradation of the welding conditions to favor the occurrence of LME cracks in a two-sheets homogeneous configuration. Detailed inspection of the welds shows that electrode misalignment, short holding time, low electrode force and long welding time constitute a propitious environment for both inner and outer LME cracks. A statistical analysis allows weighting and interpreting of the significance of the welding parameters. Electrode misalignment and reduced holding time appear as the most influential parameters in the design of experiment. Moreover, it is worth noting that standard ISO welding conditions are prone to avoid any LME cracks in the investigated two-sheets homogeneous configuration.

Highlights

The automotive industry aims at reducing the weight of Body-In-White (BIW)components in cars, which constitutes one of the means for reducing fuel consumption and carbon dioxide emission [1,2]
The aim of the present work is to investigate the effect of the different welding parameters on the occurrence of liquid metal embrittlement (LME) cracks during resistance spot-welding of an electro-galvanized 3rd generation advanced high-strength steel
The results presented above showed that improper control of the welding parameters, namely significant and severe degradation of the welding conditions with respect to the ISO standard [30], might lead to such situation favorable for LME

Summary

Introduction

Components in cars, which constitutes one of the means for reducing fuel consumption and carbon dioxide emission [1,2]. Thanks to their good compromise between lightweight and high mechanical properties, the use of 3rd generation Advanced High-Strength Steels (TRIP-aided AHSS) for structural parts represents one of the best solutions to meet this need [3]. Resistance spot-welding (RSW) of Zn-coated AHSS, as the predominant welding technique used in automotive assembly [9], is often challenging because of the low melting point of zinc [2,10,11].

Objectives

Methods

Results

Discussion

Conclusion