Pang Xuedong,Liang Xiaodong,Sun Yong,et al.Effect of Tempering Temperature on Microstructure and Mechanical Properties of High Co-Ni Secondary Hardening Steel[J].Special Steel,2025,46(03):96-101.
Pang Xuedong,Liang Xiaodong,Sun Yong,et al.Effect of Tempering Temperature on Microstructure and Mechanical Properties of High Co-Ni Secondary Hardening Steel[J].Special Steel,2025,46(03):96-101. DOI: 10.20057/j.1003-8620.2024-00209.
Effect of Tempering Temperature on Microstructure and Mechanical Properties of High Co-Ni Secondary Hardening Steel
The effects of tempering at 380 ℃- 620 ℃ on the microstructure and mechanical properties of the double-vacuum smelting secondary hardening steel were studied by optical microscope (OM), scanning electron microscope (SEM), JMat Pro software and tensile test. The test results showed that when tempering at 380 ℃-620 ℃, the matrix of the test steel changes from tempered lath martensite to tempered sorbite with the tempering temperature increasing, while the austenite increases. The tensile strength and yield strength reached their peak value at 440 ℃, which may be related to the increase of the strength of the test steel caused by the precipitation of Fe3C during tempering. The tensile strength and yield strength gradually decreased when tempering at 440 ℃- 620 ℃. Elongation and section shrinkage gradually increased. In addition, the fracture form of impact fracture changes from quasi-cleavage fracture to ductile fracture + quasi-cleavage fracture. The comprehensive test results showed that the test steel has the best mechanical properties when tempered at 496 ℃, and can achieve better strength and toughness matching.
Veerababu R , Satya Prasad K , Phani S K , et al . Austenite stability and M2C carbide decomposition in experimental secondary hardening ultra-high strength steels during high temperature austenitizing treatments [J]. Materials Characterization , 2018 , 144 : 191 - 204 .
Morsdorf L , Emelina E , Gault B , et al . Carbon redistribution in quenched and tempered lath martensite [J]. Acta Materialia , 2021 , 205 : 116521 .
Perez M , Deschamps A . Microscopic modelling of simultaneous two-phase precipitation: Application to carbide precipitation in low-carbon steels [J]. Materials Science and Engineering: A , 2003 , 360 ( 1-2 ): 214 - 219 .
Vasudevan V K , Kim S J , Wayman C M . Precipitation reactions and strengthening behavior in 18 Wt Pct nickel maraging steels [J]. Metallurgical Transactions A , 1990 , 21 ( 10 ): 2655 - 2668 .
HU Zheng-fei , WU Xing-fang , LI Xiu-qiu , et al . M 2 C Precipitate in Isothermal Tempering of High Co-Ni Alloy Steel [J]. Journal of Iron and Steel Research (International) , 2001 , 8 ( 2 ): 5658 .
Wang C C , Zhang C , Yang Z G . Effects of Ni on austenite stability and fracture toughness in high Co-Ni secondary hardening steel [J]. Journal of Iron and Steel Research International , 2017 , 24 ( 2 ): 177 - 183 .