Oil quenching Stainless lets hear some stories

Robert Hankins

Robert Hankins

Joined
May 19, 2003
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Oil quenching stainless who has tried it and what were your results.
I have had good luck using Turco coated 440C and edge quenching in Texaco quench oil.
Never a crack or warp and it gets hard as nails.
 
I use 440C exclusively for my stainless knives, and heat treat it all myself.

Basic set up rihgt now is a pile of firebricks and a bernz o matic heat shrink head set up to make a vertical forge burning propane.

Heat the blades in there tip down with the spine towards the burner (it points horizontally into the vertically opening)
Takes about 45 seconds to get about a 4 inch blade up to color (I go for a medium orange)
Lift it out and drop it vertically directly into a large can of hydraulic fluid. Leave it sit until the blade is cool enough to touch with bare hands. Wipe it down and repeat the process 2 more times.
Then it goes into the oven at 385 degrees for 2 hours, then into the freezer for 12 hours, then 2 more 2 hour cycles at 385 degrees.

Judging by the way my sharpening stones will cut it, I'm guess I'm about RC 58-59. Gives pretty good grain structure, I can get a very fine/smooth edge, almost as good as O1. Very tough too. Tested a 3" folder blade, hammering it through 1/4" X3/8" hard maple several times with a block of wood, flexing to about 15-20 degrees in both directions (springs back). Stabbing into wood and prying out didn't do much to the tip, dropping on concrete did break about 1/16" inch off the point though.
I'm carrying one as my EDC now to learn more. It doesn't hold a shaving edge as long as ATS34, or O1 (these blade are more like RC60-62 though), but its holds a useable edge very well that can be brought back to shaving with a little work on the strop or a half dozen passes on a ceramic stone.

I haven't had any significant problems with warping. Everything has come out useable. I haven't had any problems with grain growth either, like you can easily get with O1 from uneven heating.

Definitely do NOT try a water quench. I did a backspacer for a folder and wanted it hardened. Gave it a quick dunk in the oil and it was still smoking when I pulled it out. Absent mindedly dipped it in the water bucket instead of the oil and heard a nice sizzle ping ping ping .....spyderwebbed with cracks.

I'm really happy with how things are going with it right now, still have more to learn but it defintely makes for a nice blade.
 
This thread ought to become interesing.

I haven't used any 440 series yet. I wouldn't even think of oil quenching my s30v or ATS-34 stuff unless I went much thicker on the stock than what I have been using. And, since I wrap my stainless I wouldn't get a good oil quench.

RL
 
S30V I agree that goes to the pro's ATS34 have not tried yet. Read somewhere about doing D2 that way.
I know some are shaking there heads but there is always time to re-invent the wheel.
 
I've tried several types of stainless. Methods and results are much the same as Matt's. I did it just to see if I could because I don't like stainless. I feel about stainless the same way I feel about inline muzzleloaders.....Works OK but has no Soul!

I'm gonna get it for that!:D

I tried the stainless coated with Borax (440C as I recall) I think that may have improved the HT some. I've also tried air quenches using the compressor. Again, OK results. Seems to me it's easy to harden. Just try to drill some without it air hardening on you. The trick seems to be in getting the temper right. I triple temper most of my carbon knives and the stainless seems to react well to a multiple temper with a little higher heat than normal. (355 F).
 
There are a number of variables when it comes to quenching, hardenability, size , shape and use . I once brine quenched an air hardening steel, it worked and in fact we couldn't get the properties any other way. But that was a rarity. I have also quenched in water for a few seconds then finished in oil.In general we want to quench fast enough to get the properties but not so fast as to get cracking or warping. Some of the steels listed as oil hardening will in fact air harden in thin sections like blades . If you get cracks you have used too fast a quench. I must remind you to temper immediately after quenching , that is another source of cracking, not only the obvious but microcracks which cause failure sometime during use. rlinger -- is it common practice for bladesmiths to leave the blade , such as ATS-34, in stainless steel foil and air cool ?
 
Blinker, please forgive the way this tone may sound but we are the pros. There is nothing more magical about s30v than ATS-34 or others we use. If there is it is only because we do not research it well enough or ask those that do know, much like this very thread was started. In any manner it would be our fault for not asking or searching. I refuse to believe we the maker can not perform the very most important part of making the knife - the HT. Now, with all that said I am, of all us, probably the one that has most to learn about this subject.

RL
 
I have used a triple quench and triple draw on 440C and had very good results. I used a forge for a heat source and a oven to temper at 375deg. This was a prototype folder, I used this knife and carried it for several years and it was as good or better than a blade that was profesnely done. One thing that I did was use Tuco to prevent scale.
If I had a order for a stainless steel knife I would heat treat it the same way.
Way back when I was just starting I made a few knives using ATS34 and used the forge for a heat source and quenched 1 time and used the cook stove to temper 3 times for 2 hr. each at 375deg. I remember doing a rope cutting test on sisal rope ( I couldn't find hemp) I don't remember how many cuts I made but it was a lot, well over 50, what I do remember is that I finley gave up because the blade just would not dull. This was a 4" hunting knife and while I didn't test it to destruction it was a sturdy knife. This was at least 8 or 9 years ago. Dr Jim writs in his books about using a oil quench saying that it will work.
Maybe we need Rlinger to do a test for us using the stainless steel we are using now 440C ATS34 s30v bg42
Gib

PS Rlinger would you willing to do this? mabey add it to your up coming project.
 
Basically what is it I should do? Oil quench some stainless, temper and Rockwell?? Should I foil wrap it or not or both?? Outline it for me. All I have on stock right now that seems to fit the steels of interest is ATS-34 and S30V. I plan to get some BG-42 but don't know how soon. Also, I have never yet worked BG-42. I would suppose the best thing to do would be to isolate me from the HT specs and just do as asked. That may provide cleaner results.

With no atmosphere control (I use foil wrap for that) there will be some rather deep decarb that will need to be ground to get a reliable Rockwell test (just another variable to consider).

RL
 
"Blinker, please forgive the way this tone may sound but we are the pros"

'linger I am Pretty sure what he ment was People with pro equipment Not everybody has a evenheat oven most of us have a coal or propane forge and thats about it
 
Bryce, you are correct and as you stated I probably misunderstood him. I am positive he is more experienced than I but I sometimes show my stubborn ways.

RL
 
By pro's I think Blinker meant someone such as Paul Bos. Wayne Goddard says sending his stainless blades to Paul Bos is just too good a bargain to pass up if you send in bulk. Perfection in heat treat, with cryo if you want it.
On the other hand Ed Fowler posted some time ago that the best performance he'd ever gotten out of 440C was with the triple quench/draw in oil method.
It would be interesting to see how the fancier steels turn out with a forge/oil heat treat.
 
Rlinger, What I used is Turco so I suppose you should do something to cut down on the decarb. What I would like to see is one sample brought to temp (I used a full orange to judge the temp in the forge)
soak for a minuet or two then quenched in ATF, then Rockwell tested then tempered 3 times at 375 and a RC test. Another sample using the same heat and soak quenched 3 times then tested and tempered 3 times at 375 and tested.
I have some 1/8" 440C that I will send you how big of a piece do you need?
What I have is hot rolled so I will grind it down for you.
Gib
 
I doubt I am a good choice for the HT and testing unless the oven is used. Though I did build a small forge (I call it that but I made it only for HT of simple carbon steels), I do not have enough experience with a forge to judge by color. The closest I may be able to come using the forge is by doing the ol'magnet test. I could do that or use the digital oven. I have been using vegatible oil to quench but I could get some ATF if you feel it essential.

Oh, I'd say a 1 inch square or there abouts for each test piece should do it.

Please advise. RL
 
I think your heat treat oven will work just fine, orange is 1800Deg
But use the spec. that is right for the steel.
I have some short pieces 1 x 1/8 x about 3'long I will send them to you, email me your address. Gib
 
A better and more informative test, I beleive, would be to grind a fillet blade ouy of 3/32 stock and then do the HTing. I can get 440-C hard and tempered. It makes an adequate blade, but I do not feel I am getting the full potential of the steel by my HT methods.

Ken Beatty
 
I must be one of the head shakers, but I have a lot to learn. How are you guys getting 440-C hard with just a couple minutes at high heat?All my books reccomend a soak at high heat of at least 30 minutes, even for thin sections. I could never get full hardness from 440-C with a soak time less than that.

Are they making a high temp Turco nowadays? I tried it years ago but it pitted A-2 and D-2 terrible at the higher temps required.
 
Rob
Have you tried a short soak time? And did you air quench, or oil quench? I'm just using hydraulic fluid with a vertical quench. It comes out the first time and will skate a file 9 times out of 10. Generally get some de-carb on the outside for the 2nd and 3rd quenches and that makes it deceiving because it won't skate a file as well.
I probably don't have the steel at high temp for more than 5 minutes, and thats over 3 quenches total.

Ed Fowler explained why the triple quench worked in a past thread, and I sort of understood it, but can't remember it all now.
Some of it is here :http://www.bladeforums.com/forums/showthread.php?s=&threadid=222961&highlight=Why+the+long+soak
 
Rob , makes us metallurgists shake our heads too.Thats why I'm trying to get blade makers to do some tests.
 
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