Weld hardness ratio and liquid metal embrittlement crack's detrimental effect on resistant spot weld strength

Abstract

Studies on the detrimental effect of liquid metal embrittlement cracks on resistant spot weld joint strength have shown conflicting results. To help understand the cause of these discrepancies, this study will investigate the effect of liquid metal embrittlement cracks on weld strength under different hardness ratios between fusion zone and base metal. In this study, a novel methodology using finite element modelling and experimental testing reveals that the liquid metal embrittlement crack affects the weld strength differently under different weld's hardness ratio, i.e. under low hardness ratio, the cracks have a relatively big effect on weld strength while under high hardness ratio the cracks have relatively little effect. This work helps further understand when LME cracks are detrimental to strength.