Electro-Gas Welding Technology of Q345R and Microstructure and Properties of Welded Joints

Q345R-steel with thickness of 48 mm was welded by electro-gas welding technology,and then the welded joint was heat treated.The mechanical properties of the welded joint were tested according to china standard.The microstructure in the weld zone was observed.The results show that Q345R-steel suits to lower heat input welding technology;when arc voltage is(40±5) V,welding current is(440±10) A,and weld speed is 60 mm/min,the tensile strength of the welded joint reaches 515 MPa,and the impact properties can meet the weld quality requirement.