Effect of laser oscillating welding on microstructure and mechanical properties of 40Cr steel/45 steel fillet welded joints

摘要

Fillet weld is difficult to be processed due to strict requirement on the edge trimming accuracy of the plate. Laser oscillating welding is used to reduce welding defects during laser fillet welding to obtain a welded joint with a better macroscopic morphology. The present work focused on the macroscopic morphology, microstructural observation, joint strength and fracture morphology in dissimilar steel welded joints with laser oscillating welding. Results showed that laser oscillation could significantly reduce the spattering phenomenon during welding, and the shear and tensile strengths of the welded joint with laser oscillation were slightly lower than that of the welded joint without oscillation. This was due to the fact that laser oscillating welding induced more acicular ferrites in the heat-affected zone, slightly reducing the mechanical properties of welded joint. In addition, the fractural morphology of oscillation-treated sample showed a large number of dimples and few tearing ridges, which appeared as intergranular fracture.