Microstructural Analysis of a Laser Surface Reinforced 1Cr18Ni9 Stainless Steel/Q235 Low Carbon Steel Arc Weld Joints
M-L. Su, J-N. Li, Z-Y. Huang, S-J. Chang and J-S. Li
Dissimilar joint welding of 1Cr18Ni9 stainless steel/Q235 carbon steel was achieved by arc welding and a coarse microstructure was obtained in the weld seam consisting primarily of the austenites and ferrites. Then, a laser surface reinforcement technique was used to strengthen this arc weld joint surface and a fine microstructure was formed in this laser surface reinforced zone due to the rapid cooling/solidification rates of the puddle, increasing the microhardness greatly. The majority of the grains’ sizes in the laser surface reinforced zone were in a range of 0.5 to 8.0 μm. Electron backscattered diffraction (EBSD) patterns demonstrated that the grains in the laser surface reinforced zone mainly showed the green and pinkish-red colours, showing (0001) as well as the (1120) orientations.
Keywords: Fibre laser, arc welder, 1Cr18Ni9 stainless steel, Q235 carbon steel, laser surface reinforcement, microstructure, dissimilar joint