A heat-treatment that transforms the steel into a mixture of lower-bainite (the tough and hard kind) and martensite (which it already was). Since through-hardened triple-tempered 5160 is insanely tough as it is, it was really just a waste of propane and electricity, but it's my waste of propane and electricity and now it's even tougher because its time spent in molten salts. To quote your neighbors:

Bump! Dan, wll you enlighten us? <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

I have been meaning to have my RDs Austempered and maybe cryo-soaked... Thom, did your Bainitic RD9 give up any edge retention or abrasion resistance? Just curious. Or gain any, for that matter... Would there be any toughness gain in trying to get more bainite in S7 (i think it already forms some lower bainite when quenched "normally", ie mar-quenched, right?) Nice to see you here, by the way Thom...

Thom, thanks for the imput, great to have a guru around!

Thom, did you follow something you read or was this just an experiment you did, and is it noticably tougher, and did it compromise any other features of the knife?

It lost some hardness, but none I could tell. May have lost some abrasion resistance, but that's not something I look for a large knife intended for chopping, splitting, prying, and digging, so couldn't tell you. It could soft metals and hard plastics without losing a hair-popping edge (that Justin applied when he fixed the scales for me.. ..I couldn't put them back on correctly <img src="/ubbthreads/images/graemlins/blush.gif" alt="" /> ). Don't know if regular cryo would do much for 5160 as it's a simple alloy. The controlled temperature drop in a pressure-sealed room type of cryogenic processing done by folks in Dan's family might do something.


It'll have some bainite in it no matter what you do. My oil-quenched and tempered S7 bowie (somewhere around RC57-58 hardness, I think) is my only knife which passes 'the scratching post' test. Our cats' old scratching posts are pile carpet glued to some pine. All soft stuff, but it can dent or chip 5160 (martensite and bainite), 52100, and every stainless under the sun.

Nice trying to guess whom you are. Initials C. E.?

BTW, Dan's the steel-knowing man and there's a lot of good steel info here, here, and here.

Some amazing work on the 3rd "here"

Both. Read about it, contacted a swordmaker who does such things to do it to my RD-9, and then used said knife to pierce, chop, and slice wood covered with carpet, plastics, and wires. Have also chopped into a galvanized steel fencepost with my former Ratweiler and S7 RD-9 (microchipping on both easily sharpened out).

Your question is a great one to ask. I don't know how many other people believed the 'toughness' hype about S30V, but I believed it and bought knives made with that steel. It's a great steel, but it's only tough if you're comparing it to untempered glass and pigeon egg shells.

But enough about this. Stealther still needs his question answered!

That could apply to about 60-75 people over there. And more every month as they share info and techniques like crazy.

cgeyer,

Your quote doesn't mention whether the knives will be through-tempered or differentially-tempered. Close, but no cgeyer. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

LOL.....that was good!