The process and priciples of quenching

Fascinating stuff Kevin. Thanks for sharing. I use Wayne Goddards goop quench method with 5 parts lard and 1 part transmission oil. I have been using the same solution for almost a year now and I get consistent results. Is there any way , to your knowledge, of improving this method?
 
I can't speak for Kevin, but I am willing to bet that he would be a big advocate of switching to a quench oil with a speed of quench designed for the type of steel you are using. When you use an ad-hock quenching medium you can never be certain if you are achieving full hardness.
 
I suppose you are right. However I have noticed that I get wonderful temper lines when the goop is hard in the mornings. Naturally a specifically designed quenching solution would most likely work better but I have been using this method for 4 years now and am accustomed to its 'moods'. Also in South Africa where I live it is not so easy to find effective solutions that are cost effective.
 
Samurai Stu said:
Fascinating stuff Kevin. Thanks for sharing. I use Wayne Goddards goop quench method with 5 parts lard and 1 part transmission oil. I have been using the same solution for almost a year now and I get consistent results. Is there any way , to your knowledge, of improving this method?
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All of the answers you seek are actually given in great detail within this thread if you apply sound quenching principles to your current methods. However I am not certain why you are looking to improve things if you are satisfied with the consistency and economy of your current methods. I am sorry that the knowledge of blade heat treatment in print is not more diverse in your country, but there is always the internet, and perhaps this thread can help contribute to a wider array of knowledge.
 
what about quenching in Ethyl alcohol it has a higher specific heat capacity doesn't it? lower latent vaporization though.:confused:
 
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Kevin,

when you are quenching, how much can you infer from the sound as the blade enters the quench medium? I was quenching Cru Forge V in Parks 50 at 1550 and it was really "whistley."
 
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Gabe Newell said:
Kevin,

when you are quenching, how much can you infer from the sound as the blade enters the quench medium? I was quenching Cru Forge V in Parks 50 at 1550 and it was really "whistley."
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Gabe, I sent you an e-mail regarding your question, I hope to got it, if not just send me note.
 
ddavelarsen said:
That sounds fantastic - almost too good to be true. :D

I'm thinking of building (or preferably finding) a tank with dimensions like Fred described - narrow, long and the right depth to hold 5 gal comfortably. It would need a pump to direct a stream of oil toward the blade, but I haven't quite figured out the right "direction" for that stream to flow. It'd also need a heating element and ideally a thermocouple to maintain temp. Should be stainless steel with a sealable lid, if I'm going to dream up something totally silly and ideal.

Anyone have any ideas what an existing container of appropriate dimensions might be? I'd prefer not to have to have it fabricated if possible. ;)
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How about this: 20mm Ammo Can. Dimensions: L 17" x W 7" x H 15", capacity = about 7.5 gallons full.

About $17 +/- plus shipping from various surplus stores.

Al
 
You're perfectly correct, check out what I ended up with:

7FinalTest01.jpg


Here's the build.

:D
 
David

That is a first rate tutorial. I think you went the right way with this build.

After reading a couple of threads by Kevin Cashen, I have changed my quenching set up to the dimensions you have in your tutorial.

I used a 40mm canister and I use a bucket heater as opposed to your more permanent fixtures; but I believe it is the shape of the container and the amount of quenchant it holds that makes it work well.
I have used my tank for a month or so and it works great.
Being able to plunge the hot blade into one end of the tank and then "slice" the quenching oil as you move the cooling blade to the other end of the tank is about as perfect a way to quench a blade as is possible in a small shop setting.

Again, a great tutorial. I thank you for taking the time to put it together and for sharing it with your fellow forumites.

Regards, Fred
 
Thanks Fred! I had to change my process a little when I switched to actual quenching oil but I think I've got it figured out now and really like the results. Having all that circulating oil is great, keeps everything at a fairly constant temp for the small batches of knives I ever do. That heater has a thermostat, so I just turn it on and forget it; when it gets to temp it stays there. That's a good thing for forgetful people. ;)
 
o.k got a few thought on the mercury quench. the most obvious is that we have neglected to discuss its density. in order to quench a knife you wuold have force it down under the surface as the steel would float! :eek:
however this opens a new opportunity since it is so dense (13 times that of water) that you could (if only you could obtain enough mercury), make a long tube, and put the push the blade to the bottom if it is long enough and it shouldnt be that much hg then you could avoid most of the vaporization because the pressure at the bottom would not allow the hg to boil.

still highly unpractical, but even so its neat
 
There is information out there about ultrasonic quenching... eliminates the vapor stage. Would make medium quench oil nearly as fast as water.

Mike
 
Following my typical day-late dollar-short style, I'm hoping someone will overlook my tardiness in asking a couple questions on this thread.

I make custom straight razors and have just purchased an Evenheat oven to treat my carbon steel blades because Paul Bos doesn't do liquid quench stuff.

Although I make a decent blade, I'm a deer in the headlights with this new endeavor surrounding heat treating. I fear I have already made a pest of myself by sending a couple questions by PM to one of the knowledgeable members here and I don't want to risk wearing out my welcome.

I have made an effort to search the forums for answers to my questions, but this place is so huge, I'm sure I missed something that has already been answered.

I saw reference to this place for quenching oil. Would the 11-second oil be a good choice for 01 steel? Would it work for other steels as well?

thanks...
Bill
 
My question may have been answered in this thread but if so, I missed it after scanning.

I have seen many knifemakers endorse multiple quenchings, three times being often suggested.

Assuming one hits a good temperature on the first heat and that one gets the blade into the quenchent rapidly enough, are multiple quenchings really necessary? I ask in connection with both oil or water/brine mediums.

Thanks!

Andy
 
Andrew, it would seem to me that if you got it right on the first time, i. e. bringing the temp up to austinizing and not letting the grain grow, quenched immediately and beat the “nose”, reheating up to austinizing again just negates all that went before. Now multiple normalizing, I believe, will help control grain size and also multiple tempering will also help with grain size. Just my two cents. :D

Larry Theroux
 
I was browsing through my Heat Treater's guide waiting for something to finish on my mill, and came across this table:

Mechanical Properties of 1095 Steel Heat Treated by Two Methods

I'd always sort of blazed past Kevin's line about "and with a significant gain in some impact toughness" figuring it was a relatively minor effect, but Sweet Baby Jesus, more than doubling impact energy is huge.

This is a dramatic benefit. I started googling martempering and impact energy, and it's odd how unnoticed this benefit is - with commentators saying stuff that boils down to "yes, the effect is there for high carbon steels, but who cares about high carbon steels anyhow."

I found a couple of other references that produce similar results:

Smith, W.F.: Structure and Properties of Engineering Alloys, 2nd
edn., pp. 78–79. McGraw-Hill, New York (1993)

Keough, J.R., Laird, W.J., Godding, A.D.: Austempering of steel.
In: ASM Metals Handbook, vol. 4, Heat Treating, p. 152. ASM
International, Materials Park, OH (1991)

For a given hardness, martempering gets you about half-way to the toughness benefits of austempering, and of course you can get a lot harder with martempering. No wonder Kevin martempers all his metal. And given the benefit, it seems crazy that anyone who is serious about the performance of their knives wouldn't martemper.

So what am I missing? Steel is all about trade-offs and this sure seems like a free, dramatic increase in toughness for a given hardness.
 
You got it Gabe:thumbup:. Most just don't fully understand the process and how to pull it off consistently, either with or without the appropriate equipment. I have done plenty of my own impact testing and as you mentioned you can see why I martemper everything. Beyond the impact gains you also have no reason to ever lose blades to distortion or cracking again. Some alloys make the process quite a bit more difficult than others, but I choose the alloys that I do much for being able to use these techniques. I have a piece of martempered L6 that I always keep in a drawer in my lab, it has a slight kink in it from absorbing the maximum 240 ft. lbs. that my Riehle impact machine can inflict, and I was worried I hurt my tester. With that in mind it may shed some light onto why I jsut don't find bainitic blades all that interesting.

Obviously I have been well aware of these effects for some time and I am glad you found the information on your own since my approach is never to hype up and overblow claims of special techniques for making the ultimate super blade, our business already has a belly full of that nonsense. But I am very happy with the performance gains from the methods I have incorporated over the years.
 
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