Microstructure and properties of 1100 MPa grade low-carbon hot-rolled steel by laser welding

Abstract

The microstructure and mechanical properties of the butt joint of 1100 MPa grade hot-rolled low-carbon steel by laser welding were investigated by scanning electron microscopy, micro-hardness and tensile tests. The yield strength and tensile strength of the laser welded joint reached 100.2 and 99.5% of the base material (BM), respectively. However, the elongation of the welded joint only reached about 60% of BM. The lowest and highest hardness areas both existed in the incomplete recrystallization zone. The width of the softened area of the welded joint is about 240–260 μm. The element distribution has no obvious change for C, Cr, Si, Mn, Ti, etc.