D2 steel

Anywhere from 59 to 61. Lower then that and it defeats the purpose of this steel.
Scott
 
Depends on who you ask and what the blade is going to be used for really. Most say for a folder that 61.5 Rc is about optimal I think. So 60 to 62 Rc to round it out. Some of the knives of Alaska Cleavers and big blades in D2 are only Rc 58 and for a tool like that, if you insist on using D2 over something that would probably be better suited for it, that is probably a better hardness but it doesn't take advantage of all that steel can offer to use it for those kind of tools or to set the Rc that low..

STR
 
59 to 61 seems to be the best to get in the industry. Stay away from softer baldes.

61 should get the best out of this wear resistant steel.

Some go down and say for the better toughness, but steel cards say, that the advantage in that is so little compared to the toughness of other steel grades, that you better stay with the harder ones.
 
Jack142 said:
What about toughness ? if you go to 61 rc how tough will the knife be?
Jack
Click to expand...

Relativly low. But it wouldn´t be relativly tough if you drop hardness. I guess the point, where it crosses a 1% carbon steel at 59 to 60 HRC in toughness is when D2 is around 56 HRC.

If toughness is needed, choose a different steel.
 
The RC value has a "slush factor" built into it. That's why you never see it stated as 59.25 rather as 58-60. So what you think is RC59 could be RC58 or RC60. I defy anyone who uses the knives to tell me the difference. To much is made of RC values, IMHO.

The Spyderco Calypso Jr. came out with some steel called ZDP-129 that had an RC value up in the 60's. But, then Spyderco mushed it between two pieces of less hard 440 steel, probably so it was more durable and less prone to fracturing or chipping.


Here is some "techy" info for those with nothing else important to do.

http://www.gordonengland.co.uk/hardness/rockwell.htm
 
60 HRc is the preferred aim hardness but how you get there is much more important.
Austenitizing temp 1850 degrees F - holding time @ temp 30 -40 minutes
Double draw @ 500 degrees F for 2 hours per draw

A relatively fast quench from austenitizing temp all the way to room temp is important

There are other ways to heat treat D2 to 60 HRc and the finished product can be less than desireable.
 
rc values are measured by pressing a ceramic cone into the metal and judging how large the hole is compared to premade holes, from what ive heard you can measure ,5hrc or so accurately. but really i dont think you will know the difference between a 60 or 61hrc blade, trust me there are way more aspects than hrc numbers that are far more important (tempering temps maybe)
 
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