Research on Welding Process,Microstructure and Properties of N08825/L450QS Nickel Base Clad Plate

Based on the proper bevel design，the experimental plate-plate butt welding of the N08825/L450QS clad plate is conducted with the MAG+SAW+TIG welding process，and then the mechanical properties，plastic toughness，microstructure characteristics and corrosion resistance of the clad plate butt weld are investigated by means of tensile test，guided-bend test，V-notch Charpy impact test，metallographic test and corrosion test. The test results show that the tensile strength of the weld is 615 MPa，the impact toughness is up to 117 J at -30℃，and no crack is found after the guided-bend test；the microstructure of the clad layer deposited area is of austenite，the center area is of the equiaxed dendrites，and the edge is of columnar dendrites；the average rate of the weld intergranular corrosion is 1.101 g/m²，and the average rate of pitting corrosion is 0.684 mm/a；no crack is found via HIC test to the base layer weld. All the properties of the clad plate as welded are in compliance with applicable specification.