Development of Zn-Electroplated Steel Sheet Having Good Formability

The formability of electrodeposited Zn-SiO₂ composite coating has been studied. Flaking of the coating and die pick-up were hardly observed during the draw bead simulation test. Powdering resistance of the coating were also better than that of galvannealed steel. Good formability of Zn-SiO₂ composite coatings is attributed, primarily to the low friction coefficient of the coating, and secondly to the microcracking effect which release the forming stress.