Questions on Heat Treating Blade Steel
I don't know much about heat treating blades, but I was wondering if anyone has ever sent in a finished blade to get more heat treating. Can it be done? Also, would it screw up the coating on a coated blade? Does it ever cause the blade to warp? How much can the hardness be enhanced...like could you go from 58 to 62?
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Yes, it can be done. There was a guy who posted on Bladeforums or somewhere a long time ago who had Phil Wilson re-harden his M-2 710s...I think he got them up to 63 RcH or so, pretty close to full hard. Said it made a big difference in edge wear, and not a big difference in toughness.
Warping can always happen if the blade is heated unevenly. Professional heat treaters are pretty aware of such things and what they have to do to avoid it however. I think doing small batches in small ovens reduces the risk of it also.
I'm sure the heat required would cook off any coating, in fact you would probably want to grind off any coating so that it wouldn't react with the surface of the blade and make a mess. I think you want to be careful about the gases inside the oven too, you wouldn't want anything smokey in there.
dj knows a knife maker who works with M-2, he might be a good person to ask questions of. M-4 might be a different animal though, CPM.0 -
Thanks, Po! 0 -
quote:dj knows a knife maker
How did I get into this .......?? LOL
Its been a long time , I think the guys name is Chase........which is Chax knives.
He made a few handles for me in the past.
He also would make M-2 blades for any knife you wanted......he aint cheap but has a good rep.
I thought recently about having him make an M-4 blade for my 943
If BM would do something like this , I,d be all over it.
Fastjan has used the guy before too .......I think as with me , he just forgot about him.0 -
No, I haven't forgotten about him. I think he'd be a good choice if you don't mind sending your knife to Canada. I guess that shouldn't be a problem, but going through Customs is always a worry.
I was mostly wondering if a finished blade could be re-heat treated after it's been stress relieved, straightened and coated.
It seems like the M2 blades he made for DJ were all uncoated. I guess that would be cool. I could strip off the old coating and have it stamped M4 "HRC 63".0 -
Multiple tempering of steel can be done, I read somewhere on USN that Crusader Forge triple tempers S30V to hardness where the knife can cut nails with very minor damage done to the edge.
They must have an internet site you can check and get more info.0 -
thanks, Archer. I also just noticed online that they sell small heat-treat ovens for knife makers. The small one for folding knife blades has a box that is 6"high x 8" x 8" and will go up to 2,000°F off 120V household current for $676.97. 0 -
The local professional heat treating outfit will heat treat knife blade for about $10-20...depending on the steel and number of blades in a batch. If I were interested in such a thing, I would have them do my blade for me. Once the blade was clean (coating sanded off), it is just a matter of heating it to the right temp, and tempering it correctly. Ask around with some knife makers you know, find out who does the heat treatment for them. If the same outfit isn't interested in doing one blade for you, you might be able to put your blade in with the next batch the knifemaker sends in. A pro will do your blade to spec, in a Nitrogen purged furnace, plus they will cryo quench it for you. All for about the cost of a fifth of good Kentucky bourbon. 0 -
If you are going to get your HSS rehardened, see if you can get someone who uses salts. The blade can be soaked cooler for a shorter period of time and it will produce :
-a harder blade
-less retained austenite
-better primary carbide dispersion
-finer aus-grain
Thus it will be :
-stronger
-tougher
-higher wear resistance
-improved edge stability
If should be obvious to them, but mention anyway that the blade is being rehardened as they have to account for that.0 -
Good thread, guys. This type of content is why I came to the forum in the first place. 
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