How To Heat Treat 9Cr18Mo Stainless Steel
9Cr18Mo is a stainless knife steel in the 440C family.
Heat treatment requires good temperature control and for optimal results, also a cryo treatment.
For instance dry ice and methylated alcohol mixed in a cooler.
Decent results can be achieved without the cryo step.
Note: All times start at temperature, meaning not until the steel is the listed temperature.
Ramp times are not included in the time listed.
How to Heat Treat 9Cr18Mo or any other 440C family steel:
- Hold at 760 C for 10 mins (1400 F)
- Hold at 1040 C for 30 mins (1900 F)
- Quench can be still air, plates, or even oil (Air quenched steel so plates or oil not required)
- If possible: -70 C for 30 mins (-95 F)
- Temper at 190 C (375 F) for 2 hours, cool in tap water and temper for 2 hours again
- this will give an estimated 59-60 HRC if cryo step is included
*Disclaimer: We are not metallurgists and this is listed as helpful advice for a starting point only. Individual equipment may vary and for best consistency we recommend starting with this recipe and having the steel hardness tested. Then modify your process and test again.