The Microstructure and Mechanical Properties of the Laser Microwelding Joint for SUS 321 Sheet

Abstract

The butt-joint of 0.3 mm SUS 321 plate was welded successfully by micro-pulse laser and the processing parameters were optimized through orthogonal experimental design. The effect of the processing parameters on the microstructure and mechanical properties of the joint with OM, electronic precision stretching machine and other analysis and detection methods. The results indicate that the butt-joint will possesses highest tensile strength of 550 MPa when the optimized processing parameters are the percentage of pulse power of 18, pulse width of 4 ms, pulse frequency of 2 Hz, and the strength of the joint is 98% to the strength of basic metal. The microstructures of joint with high tensile strength are composed of small equiaxial grains in the weld center zone and columnar grains in fusion zone. The microhardness of the joint is higher than that of basic metal.