Special features of the winding bend test

Summary

This paper deals with the resistance spot weldability of steel to aluminium alloy using an intermediate layer of aluminium clad steel. Five types of clad sheet with various steel/aluminium thickness ratios were produced by hot rolling. The mechanical properties of the clad sheet changed with the thickness ratio and ranged between those of steel and:those of aluminium sheet. The peel strength of the steel/aluminium interfaces was greater than 25 N/mm.

Materials used in spot welding were 0.8 mm thick EDDQ steel sheet, three types of 1.0 mm thick aluminium alloy sheet and the clad sheet mentioned above. Spot‐weldability, including suitable welding current, nugget diameter, tensile shear strength and thickness of the intermetallic compound layer formed at the interface of the clad sheets, changed with the thickness ratio of the clad sheet. From these results, it was concluded that spot‐weldability was affected by the thickness ratio of the clad sheets.

Spot‐weldability was also affected by the alloying elements in the aluminium alloy sheet. Tensile shear strength and nugget diameter varied in various types of aluminium alloy sheet.