Abstract: Low temperature heat treatment (240 and 300 ℃) of ZG06Cr13Ni4Mo martensitic stainless steel after welding was carried out. The microstructure, mechanical properties, hardness and residual stress of the joints after different low temperature heat treatments were studied by means of OM, tensile and bending test, hardness test and residual stress test. The results show that after low temperature heat treatment, the microstructure of the HAZ of the joints is tempered martensitic and carbide, and the microstructure of the welding zone is low carbon martensitic, block martensitic and carbide. Meanwhile, the tensile strength of the joints varies little, and the hardness decreases slightly. The residual stress at welding zone of the joint after 240 ℃ low temperature heat treatment is relieved by 69.1%.

Key words: martensitic stainless steel, low temperature heat treatment, mechanical properties, residual stress