Microstructure and properties of hot-rolled high strength bainitic steel by laser welding

摘要

Microstructure and properties of laser-welded butt joint of hot-rolled high strength bainitic steels were thoroughly investigated by scanning electron microscopy (SEM), tensile and micro-hardness tests. Corrosion property and work hardening behavior of welded joint were analyzed and compared with the base metal. All the laser welding samples fractured from base metal are showing that the joint strength is higher than that of base metal, although they share similar elongation. Since different microstructures appear near weld seam after laser welding, the variation of strain hardening rate and instantaneous n-value of the first deformation stage of laser welding joint has large fluctuations, and the welding joint is easier to be corroded in the same environment.