12C27 Air Quench ????

buckaroo

Well-Known Member
I am getting ready to HT some 12C27 blades. My question is can I air quench this steel or is it strictly an oil quench steel.
Thanks, Dave
 
I have done a plate quench for 12c27, 1975F for 10min ( small thin blade) temper twice for 2 hrs @425. Had inspection at my machine shop test it, 58/59 hrc
 
Thank you for the information. I said air quenching but will be using plates. Brandon0403 did you cryo the blade to get 58/59 hrc or just plate quench and temper?
 
Buck - While true cyro (-95ºF is dry ice and NOT cyro) is helpful, it certainly is NOT a requirement with Sandvik steels. As you read in the thread I linked to Sandvik gives 3 types of HT - and they ARE talking about for knife blades, this this steel is designed and manuf'd by Sandvik for knives. I have used dry ice for cyro for one batch. The rest of time I've used -5Fº for HT which does seem to work good.

When Sandvik and other manufacture folks talk about Air Quench, they are referring to laying blade on a grated type belt with cooling air (no idea of air temperature) blowing across blades. Plate quench is when the blade is clamped between to heavy metal plates - usually aluminum plates.

Ken H>
 
Last edited:
Just for clarification, in the knife heat treating lingo, true cryo is liquid nitrogen temps (-300°F+), while sub zero is the dry ice temps of (-100°F), and the Sandvik steels do not need cryo, just sub zero.
 
Just for clarification, in the knife heat treating lingo, true cryo is liquid nitrogen temps (-300°F+), while sub zero is the dry ice temps of (-100°F), and the Sandvik steels do not need cryo, just sub zero.

everything samuraistuart wrote is correct! I don't know what I was thinking in prior post...... well, obviously I wasn't thinking! Sandvik does note that even freezer temp of -5ºF is beneficial, perhaps half way between -95ºF and no freezing at all.

Ken H>
 
Yes Sandvik pushed his developement of edge steels toward the research for the best edge stability and rust resistance.
To reach their goals they want the minimum necessary alloying, so they minimize the stabilization of the austenite vs. other more alloyied SS. That is why, depending on how much carbon going into solution at the different suggested austenitizing temperatures we have different sub zero quenching temperatures to get rid of the minimal related RA.
Of course we get more hardness if we have the possibility to use the max austemp and the coolest of the quenches, but the other available combinations give us acceptable strenght and no RA issues, which is even more important than the couple points of more hrc in terms of edge stability.
 
Back
Top