Abstract: The microstructure and properties of 05Cr17Ni4Cu4Nb martensitic stainless steel were observed and tested by means of metallography microscope, scanning electron microscope, transmission electron microscope, hardness and impact tests, respectively. The effect of tempering on its intergranular corrosion sensitivity was studied by intergranular corrosion test. The results show that after tempering at 650 ℃ for 2 h, the density and size of the Cu dispersion-strengthened phase in the tempered tested steel decrease and increase, respectively. The inverting austenite phase forms and grows along the boundary of the original austenite phase and the original martensitic lath, the Cr-containing carbides decompose, and the Cr element is separated out to form a strip precipitated phase, but the distribution of Cr element is more uniform, resulting in a decrease in the strength of the steel, an increase in toughness, and the intergranular corrosion sensitivity of the material is reduced due to the supplementation of Cr element in the original Cr poor region.

Key words: tempering treatment, 05Cr17Ni4Cu4Nb martensitic stainless steel, intergranular corrosion, microstructure, properties