Iranian Journal of Manufacturing Engineering

Iranian Journal of Manufacturing Engineering

The effect of continuous hot-dip galvanized steel coating thickness on the properties of dissimilar steel-magnesium joining using resistance spot welding

Document Type : Original Article

Authors
Ali Dehghani 1
Sadegh Bidarmaghz 2
Mohammad Sedighi 3
1 PhD Student, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
2 MSc Student, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
3 Professor, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
10.22034/ijme.2024.418127.1841
Abstract
The use of light metals instead of steel in parts of the vehicle body to reduce weight and thus lower fuel consumption has attracted the attention of car manufacturers and researchers. Therefore, this study investigates the dissimilar joining of magnesium and steel sheets by resistance spot welding and the thickness of galvanized steel sheet coating is considered as an effective parameter for the joint strength. The materials used in this work were AZ31B Mg alloy sheet and hot-dip galvanized steel sheet. To investigate the influence of the coating thickness on the joint, two coating thicknesses of 5 and 10 µm were applied to the steel sheet. also to balance the thermal generation on both sides of Mg and Steel sheet, two electrodes with different geometries were used, flat electrode on the steel side and domed electrode on the Magnesium side. Tensile-shear tests were performed on the samples using a tensile testing machine and the microstructure was analyzed using optical and SEM microscopy. The results show a 13% increase in joint strength at a coating thickness of 10 µm. The studies show that increasing the coating thickness from 5µm to 10 µm, reduces the grain size in the nugget  and thus increases the strength.
Keywords
Spot Welding Process
Magnesium
Galvanized Steel Sheet
Dissimilar Joints
Coating Thickness
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