12c27 Stainless Steel

12C27 Stainless Steel

Swedish Stainless Steel 12c27 from Swedish manufacturer Alleima (formely called Sandvik until 2022).

This is a very  popular stainless blade steel due to ease of heat treat and ok edge retention.

The steel comes already annealed from Sweden, annealed means the steel is "soft" and workable with hand tools.

It can be drilled, filed, ground and shaped with relative ease. Look up hand filing jig on youtube for an easy to make hand filing jig for making even bevels.

This steel will need to be heat treated, either at home in temperature controlled gas forge or kiln, or by sending it away for professional heat treatment. 

Heat Treating 12c27 in a gas forge to 56-58 HRC:

• Heat steel to 1080 C (1976 F)
• Hold for 5 min (for 2.5 mm thick blades)
• Quench in Canola oil, heated to 40 C (104 F)
• Into freezer* (optional step, aiming for -20 C)
• No hold time, just get blade cold and quickly onto Tempering
• Temper in stove, at 170 C for 2 hours  (338 F)
• Let blade cool to room temperature
• Temper in stove, at 170 C for 2 (338 F)

*Sandvik/Alleima suggest 3 hardening profiles; with no freeze, -20C and -70C. 

The difference is only a couple of HRC points in hardness from no freeze to -70 C profiles. So this steel can be hardened to a great blade without investing in a dry-ice or cryo setup.

Heat treatment, more info: LINK