Comparative analysis on mechanical properties of dissimilar steel welded joints by LMHW and MIG welding

Laser-MIG hybrid welding (LMHW), which combines the advantages of both laser and arc independent heat sources as well as greatly avoids their disadvantages, is a new welding method with great application prospects in the fields of automobiles, ships, petrochemicals, etc. The differences in microstructure and hardness distribution of the dissimilar steel welded joints of 25CrMo4 and 33MnCrB5-2 by LMHW and MIG welding were investigated. The results show that the effect of LMHW was better than that of MIG welding, performing an uniform and full weld seam. LMHW joints exhibited higher overall hardness, finer microsfructure in welding joint centre and better joint quality than MIG welding joints. Specifically, the overall hardness of welded joints of LMHW was 30% higher than MIG welding.