The 12 Cr1 MoVG and T91 dissimilar steel were welded by automatic tungsten argon arc welding. The effect of different heat treatment conditions on the mechanical properties of dissimilar steel welded joints was studied. The results show that the first pass rate of dissimilar steel welded joints reaches 100%. Under different heat treatment conditions

the fracture positions of normal temperature and high temperature tension are on the side of 12 Cr1 MoVG base metal

while the high temperature tensile strength and normal temperature tensile strength of dissimilar steel joints after heat treatment are lower than those of samples without heat treatment. The high temperature tensile strength and normal temperature tensile strength of dissimilar steel joints after heat treatment are 519 MPa and 555 MPa

respectively

which are different after heat treatment. The tensile strength of seed steel joint at high temperature and at room temperature are 554 MPa and 653 MPa respectively.