60Si2Mn heat treatment process specification

1. Critical point temperature (approximate value) Ac1=755 (735), Ac3=810, Ar3=770, Ar1=700, Ms=305.

2. Specifications for thermal processing The starting temperature is 1100 and the ending temperature is 850.

3. Specifications for softening treatment of cold-pressed blanks The softening temperature is 740~760°C, heat preservation for 4~6 hours, and then cool down to ≤600°C at a cooling rate of 5~10/h, and then air-cooled after being released from the furnace. The hardness before treatment is ≤255HBW, and the hardness after treatment is ≤217HBW.

4. Complete annealing specification Annealing temperature 840~860, heat preservation 2~3h, after the furnace is cooled to 500, it is air-cooled after being released from the furnace, and the hardness is 185-255HBW.

5. Ordinary quenching and tempering specifications Quenching temperature (870±10), oil cooling, tempering temperature (480±10).

6. Standards for isothermal quenching and tempering Quenching temperature is 870°C, heat preservation for 20 minutes, oil cooling when out of the furnace, immediately put in 250 nitrate salt bath for 20 minutes, and air cooling after removal from the furnace.

7. Best heat treatment specification Preliminary heat treatment: oil cooling and quenching at 870°C → heating and holding at 790°C for 25 minutes → rapid cooling to 680°C and holding for 40 minutes → furnace cooling to 500°C and air cooling.

8. Final heat treatment process: quenching temperature 870, isothermal temperature 250, isothermal time 20min.

Typical application of 60Si2Mn

1) After the steel nut cold forging die is quenched and tempered at a high temperature of 920~950, its service life is longer than that of a die quenched at normal temperature