Dependence of overload performance on weld attributes for resistance spot welded galvanized low carbon steel

Microstructure and failure behavior of galvanized low carbon steel resistance spot welds were investigated. Failure mode, peak load and energy absorption obtained in tensile-shear test were used to describe spot welds performance. It was found that weld fusion zone size, electrode indentation and expulsion can significantly affect the mechanical performance of spot welds. Failure mechanism of spot weld which fail via pullout mode during tensile-shear test was “through thickness” localized necking in the base metal. However, those spot welds which have experienced severe expulsion during welding, failed at the fusion zone/HAZ interface. This can contribute to the reduction in energy absorption capability of spot welds due to the harder microstructure of the fusion zone/HAZ compared to the soft ferritic base metal.

[1]  Hongyan Zhang,et al.  Critical specimen sizes for tensile-shear testing of steel sheets , 1999 .

[2]  M. Pouranvari,et al.  Microstructure and failure behavior of dissimilar resistance spot welds between low carbon galvanized and austenitic stainless steels , 2008 .

[3]  J. Feng,et al.  Nugget growth characteristic for AZ31B magnesium alloy during resistance spot welding , 2006 .

[4]  Majid Pouranvari,et al.  Effect of weld nugget size on overload failure mode of resistance spot welds , 2007 .

[5]  Xin Sun,et al.  Effects of fusion zone size and failure mode on peak load and energy absorption of advanced high-strength steel spot welds , 2008 .

[6]  Majid Pouranvari,et al.  Effect of expulsion on peak load and energy absorption of low carbon steel resistance spot welds , 2008 .

[7]  Hongyan Zhang,et al.  Resistance welding : fundamentals and applications , 2005 .

[8]  M. Zhou,et al.  Relationships between Quality and Attributes of Spot Welds A spot weld's strength can be determined by the geometric characteristics and mechanical properties of the weldment , 2003 .

[9]  Sheri Sheppard,et al.  Resistance Spot Weld Failure Loads and Modes in Overload Conditions , 1997 .

[10]  M. Pouranvari,et al.  Relationship between failure behaviour and weld fusion zone attributes of austenitic stainless steel resistance spot welds , 2008 .

[11]  Wei Chen,et al.  Three-dimensional finite element analysis of the mechanical behavior of spot welds , 2000 .

[12]  Horst-Hannes Cerjak,et al.  Mathematical Modelling of Weld Phenomena 7 , 2002 .