The Effect of Peak Power and Pulse Duration for Dissimilar Welding of Brass to Stainless Steel

Abstract

A pulsed Nd:YAG laser was used to weld overlap joint between H62 brass and 316L stainless steel in thermal conductivity welding mode. Effects of peak power and pulse duration were investigated under the condition of constant pulse energy. Optical microscopy (OM), scanning electron microscope, and X-ray diffraction were used to analyze the microstructure, defects, and intermetallic phases in the interface, respectively. Microhardness test and tensile test were carried out to identify the mechanical property on the welded joints. The results showed that the microstructure, penetration-to-width ratio (ϕ), and mechanical properties were affected by the combined effects of peak power and pulse duration when the pulse energy was constant. When the magnitude of the peak power equals to 1846 W, both of penetration-to-width ratio and microhardness in the welded joints stayed to a minimum value. But if the magnitude of the peak power is less than 1846 W, the welded joint has the fewer defects, superior microstructure, and mechanical properties while comparing with the greater peak power.