Flash butt welding on microstructures and mechanical properties of joints for high strength acid resistant steel

In this research, the 600 MPa acid resistant steel was used as flash butt welding base material, to study effect of different upset allowance on microstructure and mechanical properties joints. The results can be obtained follows: with increase allowance, it has a significant elongation, ferrite content in heat affected zone increases, joint strength first increases then slowly decreases. When is bigger than 4mm, there are wide large bainitic ferrites coarse grained zone, deteriorates sharply. 3-4mm, welded sample best, tensile 686-708MPa, yield 610-636MPa, elongation higher 13.77%. matrix strengthened effectively by forming grain refinement dispersed granular bainite proper allowance. hardness distributions joints display difference regions.