440C Stainless Blade Steel

440C Stainless Blade Steel 

High quality, high carbon Stainless Steel for blades, high in chromium for good corrosion resistance in the kitchen or marine use.

440C is a tough, "very stainless" steel - it is harder to grind than some of the other stainless steels, and will not etch as evenly as for instance AEB-L if wanting to etch and stonewash. It holds a great edge.

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 :

• 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

Heat treatment: https://nordicedge.com.au/how-to-heat-treating-440c/ 

* 440C is an air quenched steel so plates or oil not required but works fine. Plates are often used to help the blade cool down straight.