Explanation
It is also called austempering. The quenching hardening process of heating and austenitizing steel and quenching it into a cooling medium whose temperature is slightly higher than ACA. Isothermal holding makes steel undergo lower bainitic transformation, and then cooling it to room temperature. Compared with martensite structure, lower bainite structure has higher toughness under the condition of the same strength and hardness, but lower bainite cannot be obtained by continuous cooling in steel with normal chemical composition, so isothermal quenching is required. The isothermal temperature of isothermal quenching is in the lower bainitic transformation temperature range, generally 250-400 ℃, and the isothermal time is determined according to the isothermal curve or S curve of steel. Isothermal pan fire is applicable to mechanical parts made of alloy steel and high-carbon steel requiring higher hardness and higher toughness.
Classification
No classification at present.