440C is a high quality, high carbon Stainless Steel for blades, high in Chromium for good corrosion resistance in the kitchen or marine use.

Composition:

C 0.95-1.10%, Si <0.80%, Mn <0.80%, P <0.035%, S <0.030%, Mo 0.40-0.70%, Cr 16.00-18.00%

How to Heat Treat 440C 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* 
• 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

*Air quenched steel so plates or oil not required but often used as oil is a handy way for most makers to cool blades, and plates often used to help retain a straight blade while cooling down.

Additional detail:

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.

*Disclaimer: 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 for optimal results.