Effect of heat treatment temperature on the mechanical properties of low-temperature high strength maraging steel

The effect of austenitizing temperature on mechanical properties of 00Cr9Ni9Co5Mo3 corrosion resistant maraging steel has been investigated. The results show that the recrystallization temperature of experimental steel is 850 °C. The austenite formed by non-diffusion reverse αʹ→γ transformation inherit high density defects of the forging structure when solution treatment temperature is below recrystallization temperature. High-hardened martensite is formed during the cooling, the strength keeps a high level. Meanwhile, high-hardened austenite improves the resistance of γ→αʹ transformation in the cooling process, which leads to more retained austenite in the steel and guarantees good low temperature toughness. The increasing of the pretreatment can further improve the low temperature toughness. When the pretreatment is added, the low temperature toughness is improved further, and the mechanical properties of materials are stable with the fluctuation of pretreatment temperature.