Microstructure and Mechanical Properties of Laser-Welded Joints between DP590 Dual-Phase Steel and 304 Stainless Steel with Preset Nickel Coating

Abstract

Dissimilarities in metal laser welding lead to brittleness in welded joints due to differences in the thermophysical and chemical properties between dissimilar base materials. To overcome such brittleness, the addition of a preset coating onto the base materials as an interlayer is a method for attaining reliable welded joints. Nd:YAG laser butt welding of DP590 dual-phase steel and 304 stainless, both with a thickness of 1 mm, was performed with a preset nickel coating as an interlayer using an electroplating process. The relationship between the microstructure and the mechanical properties of the welded joints was researched, the microstructure and composition of the weldment were analyzed, and the microhardness, tensile strength and corrosion resistance were tested. The results showed that the preset nickel coating increased the content of Ni element in the welded joints, which is beneficial to the formation of lath martensite. The average hardness of the welded joints increased by 12%, and the tensile strength was higher than 370 MPa. The corrosion rate of the welded joints can be slowed down, and the corrosion resistance can be improved by increasing the nickel coating.

Investigating electrochemical corrosion at Mg alloy-steel joint interface using scanning electrochemical cell impedance microscopy (SECCIM)

“…Sidhu et al used bulk corrosion techniques to understand the effect of the FSW process on the joint of Al and Mg alloys, which suggested that FSW techniques yields higher corrosion resistance based of the PD polarization curves 32 . Zhang et al looked at the effects of Ni coatings on DP590 and 304 stainless steel and found an increase in corrosion resistance 33 . These studies suggest that the joining portion of the two similar metals have distinct electronic properties, that affect the joined metal as a whole.…”