Electrodes Type Effects on Welding of Copper to 304 Stainless Steel and Analysis of Heat Distribution, Microstructures, and Mechanical Properties

Shielded metal arc welding achieves copper to stainless steel joints using Cu-based and Fe-based electrodes. ANSYS and SOLIDWORKS models predicted the welding heat distribution and HAZ dimension for both welding electrodes. According to the heat distribution results, deformation and stress distribution for both models were calculated. ANSYS software was used to calculate the HAZ and fusion zone width for both sides and both electrodes; the results showed 1.9 mm on the stainless-steel side, 6.24 mm on the copper side for ECuSi, and 6.7 mm for the stainless-steel side, 7 mm for the copper side in E308 sample. The stress models illustrated higher stress on the stainless steel side for both the welding sample and in fixtures for both sides. The estimated deformation results were 0.40 and 0.48 mm for ECuSi and E308, respectively. Weld zone in Cu-based filled joint consists of uniform structure with Cu solid solution phase. Immiscible Cu and Fe mixture causes weld segregation in Fe base electrode joint. Weld zones containing a combination of phases in the Fe-based filled joints exhibit greater microhardness than the Cu-based joints. Cu-based joint achieves highest tensile value, reaching up to 80% copper tensile strength. Heat treatment causes reduction in dislocation density and increases grain size, resulting heat-affected zone (HAZ) softening on both joints copper side. This softening makes HAZ susceptible to fracture during tensile testing. Every joints fractures in ductile manner and plastic deformation is concentrated on softened copper side. Welding joint filled with Cu displays the most plastic deformation due to the significant displacement of both the welding zone and Cu base metal. This deformation primarily produced by weld high plasticity, which helps reduce stress concentration.