Why the long soak?

Didn't mean to jump on you Graymaker. Pretty 'cool' set up, never thought of that.

Just out of curiosity, have you tried the new CPM steels? With the particul metalurgy they should overcome many of the disadvantages of conventonal stainless.
 
Nice water tube Dan. I need to try that one. As far as the "Rosebud" ;) tip on my torch. Hardening stainless with the torch has been mostly experimental so far, but since using Ed's triple quench method the last couple of days I think it has more reasonable application now. I used the rosebud to heat no more than the bottom third of the blade, not letting it get anywhere near critical temp up near the spine of the blade. Once I've used a magnet to check the heated edge I continue to apply the rosebud for about another minute keeping the heat even, then quench. For the quench I've used an edge quench with "goop", oil and a point down oil quench. Since only the edge is heated to critical the spine never has a chance to harden. All three quenches turned out with very similar effects so far. Though, warpage was more frequent with the "goop" when blades were intentionally ground thinner than I normally quench at (about .025-.030"). After the third quench and third temper (375 deg. an hour each) I like to run the rosebud up the spine. Maybe it's just a habit from carbon steel, but I think it helps gives a litte better flexability to the spine. I suggest trying the triple quench, it seems to make one hell of a difference in the edge structure so far. Now I'll have to get some other stainless steels, like ATS-34 and try this out. It may have to wait for while though, I really have to get back to these orders and working with carbons again (gonna start forging damascus this summer).:D

J.
www.mountainhollow.net
 
I am honored that you gentlemen have seen fit to explore the multiple quench with 440 C. Thank you for having enough faith in what I said to invest your time and materials.

How about some of you delving in to trying ATS34 and some of the other stainless to the same kind of experiments. I would love to read what you find and enjoy sharing with you as your ingenuity and intdividual natures blend into developing something that may be better than what we now know as the limits. Who knows? Blade forums may very well become the shop and school I have dreaming about for years.

Thanks to all of you!
 
I see what your doing J.
you getting a lot of shale with out the ss
wrap?
   Will I didn't think you were jumping on me,
  just saying if someone, anyone disagrees with me
let me know, give it to me with both feet.
it's a great learning method, a good debate
  can make one do a bit of research.

I at least double draw with a nitrogen soak after
the first draw. if some of you are not freezing
ss to at least -300 your missing out on up to 30%
(some say more) edge holding ability.
the only thing I don't like about heating SS past
critical tooo many times is you lose
carbon and you need the carbon..any thoughts ?
the Japanese put in carbon by forging it in
with the coke that they fired with.
ED can I get your input on this, carbon loss?
 
Just the cost of doing business J. it's like
.35 per blade, 8 times less then a belt
loosen up some of your moldy money..:p
 
Greymaker: Good question! Carbon loss is a function of time and temperature combined. Just entering into the critical zone and quenching does not provide enough heat or time to loose any measurable amount of carbon.

Rex shot a chermistry on a piece of 5 1/2 inch round bar. Doc forged that piece to a 2 1/2 x 2 1/2 x 14 inch bar. Rex sent it to me. I then forged that bar down into billets on my 150 pound Beaudry that I could work further down into knives on my 50 pound Little Giant. I forged the blades, hardened and tempered them,(all multiple quench and temper) then sent them to Rex with the scale remaining on the blades. Rex shot a chemistry on the surface (scale) found it to be one point down on carbon. He then polished of a couple of thousands, (much less that I would when grinding to the cutting edge) and shot another chemistry. There was no measurable carbon loss from the parent bar of steel. The whole story will be in upcoming issues of Blade.

I hope I answered your question.
 
Well, I had a mis-ground ATS-34 blade laying around, and decided to give it an edge quench. Needless to say I now have more questions than answeres.

I brought the lower third of the edge to non-magnetic, and quenched 3X in oil, the same oil I use for 52100. After sitting in the oil for a couple of days I finaly got back to it and checked it with a file. It was not much harder than in the anailed condition, and I thought it was a waste of time. I figured what the heck, and sharpened it and proced to test the edge. It almost passed the brass rod test, was a little soft, but not to bad. I then resharpened and tried some cuts on 1/2" sisile rope. It blew me away! It cut close to a cryoed blade at RC60! Keep in mind that it has not receved a temper or cryo treatment. I broke the tip off and the grain looked much finer than ATS normaly does. So I then tried the 90deg. flex. The blade bent to 90deg., but the sharp bend indicated a weak blade. I pounded on the spine with a hammer with the blade against a block of mild steel and istead of cutting into the steel the edge deformed.

Every thing tells me the blade didn't harden, but the finner grain and cutting ability tells me something happened. What happened? I ain't got the faintest idea:confused:

I normaly dont' mess with much stainless, this was left over from the last batch I sent to heat treat, so it'll be awhile befor anymore experiments. But I am intregued.

One final though, since stainless isn't stainless unless fully hardened, wont an edge quench defeat the purpuss of useing a stainless steel?
 
Will: I love it, way to go! the questions you have you get the honor of experimenting and seeing about the stainless being stainless. Nobody but you can find out with that blade.

As to the hardness, a 52100 multi quench blade will out cut a single hardened blade and still be a couple of points softer on the Rc. (and much tougher). A 60 rockwell mq 52100 blade will scratch a steel over 62 rockwell. We believe we know why with the 52100 but the ATS will take some exploration to find the answer. It may relate to grain size, wrapped carbide size and dispersion or many other consequential variables due to the nature of the ATS that you were working with. Try to get some history on that steel and maybe some more like it and you are off to the races. By the way, etch that blade and let us know what you see!

THANKS for the information. I have some ats waiting for my attention, but have to pay some bills then two shows and play time again.
 
Will, I've found the same thing with some of the mystery steels I've been playing with. I also had the same results with a wrench I forged into a knife over the weekend. They seem soft as butter but cut and hold an edge. On some they become brittle before tempering even though they seem soft. I am still trying different quenches and tempering techniques on some to see what happens. The grain is very much reduced on some. I am relearning something that should have stuck with me. There is more to cutting ability and edge retention than hardness alone.
Every time I start getting cocky about knife making something appens to remind me how much I have to learn.
 
Got to make this short, just got called back to off-shore,

Ed, Peter, the ATS-34 came from the same bar that I ground 4 other blades from and sent off for heat treat and they came out fine. When I get back I'll polish the blade up and do an etch, then lay it out in the wheather and see how long it takes to rust.

I don't put much faith in it, after all the grain size is nowhere near as fine as 52100, and even pro heat treated ATS-34 cant come close to 3x quenched 52100. But it was fun, and raised a lot of questions, so now the cureosity is bugging me to find out why, and if I can do it again. I also wonder if more than 3 quenches or maybe a delay between quenches will help it. Because to be a servicable blade it will have to be harder.

Unfortunatly it's off to work I go, as you said Ed, it's time to pay some bills.
 
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