Is 62rc too hard for A2

[rockfishbrewery]

Hello,

I'm working on a santoku/gyuto inspired kitchen knife of the below spec:

Steel = A2
Thickness = ground from 3/32 stock
Blade Length = 7-8in
overall Length = ~14in
Hardness = TBD

I read about how A2 has a "sweet spot" at 60rc. I would like to make it as hard as possible for maximum edge retention. Can I safely push it to 62rc without sacrificing too much toughness?

Thanks in advance for any input.

 

[Stacy E. Apelt - Bladesmith]

Make it at 62 and brass rod test the edge. If it holds, OK. If not, retemper to Rc-60.
For a fine work slicer, 62 works in S35VN, so it might work in A2. If you have cryo available, it would be good to give it a run through.

Try:
Pre-heat at 1455F for 15 minutes
Ramp to 1800F austenitization for 15 minute soak
Plate quench to ambient
stress temper at 300F for 20 minutes.
Cryo treatment for 30 minutes
Temper twice for two hours at 375F
Should yield Rc62

 

[Nathan the Machinist]

A2 does well at 62. You'd be towards the high end, but still within its sweet spot.

 

[JBS TOOLMAKER]

For kitchen work 62 would be great.

 

[Danbo]

I remember reading that A2 is at it's best at 60, so I think 62 is a little high.

 

[Mitchell Knives]

I have heat treated numerous A2 pieces to 61 - 62 HRC without issue.

Then again, they were all fine slicers. YMMV.