A Detailed Examination of Weldability Lobes for a Range of Zinc-Coated Steels

The objective of this study was to investigate the weld ability of four tyes of coated steels. These materials include: uncoated, hot-dipped galvanized, electro-galvanized and galvannealed steels. “Statistically significant” weld ability lobes were evaluated for each material. Dynamic resistance traces were also evaluated.

The following conclusions were obtained from the results. The minimum-nominal current range/lobe width ratio indicated the mode of button growth and correlated well with the expulsion button size. The lobe width/standard deviation ratio was found to be a measure of weld stability. The dynamic resistance traces on uncoated steel correlated very well with the observed button size; however, similar correlations could not be made with respect to the zinc coated steels. It was found that the variability of the averaged dynamic resistance traces were consistent with the variability of the corresponding weldability lobes.