Zn-Fe 합금 도금강판의 점용접성에 관한 연구 = A Study on the Spot Weldability of Electroplated Zn-Fe Alloy Steel Sheet

다국어 초록 (Multilingual Abstract)

Spot welding is widely used in automobile assembly lines. Electroplating of Zn-Fe on steel sheets is increasingly used in assembly lines, because of its good spot weldability, formability and corrosion resistance.
In this study, to evaluate spot weldability, tensile shear strength and cross tensile strength of steel sheets electroplated with Zn and Fe up to 0.7mm thickness were investigated, and these mechanical properties were compared with those of steel sheets electroplated with Zn only.
The thickness of electroplated steel sheets was measured with SEM.
The following conclusions were obtained.
(1) In spot welding, the weldability lobe was getting wider and directed toward low currency direction, in steel sheets electroplated with Zn-Fe compared with those electroplated with Zn only.
(2) Electrode force and welding time obviously affected the ultimate welding strength, and the range representing constant ultimate welding strength was observed.
(3) When Zn-Fe were electroplated on steel sheets, the ductility ratio was increased in optimal welding condition, indicating that good weldability was obtained.
(4) Around 8.5KA where optimal strength existed, by spot welding, the amount of the
electroplated layer was observed to be reduced by approximately 15% in thickness.