I'm looking for something to quench blades from ~1500 F to about 400 F. All the common oils have flash points well below this, and I dont want to get into a salt bath, since its just for home/hobby work. Any ideas on what I can use? Tin melts at 450, and some oils might work at 300, or maybe peanut oil at 350, but thats the highest I've seen. Of course, if I can melt tin, then a similar temperature salt bath might be possible. Thanks all.
-
The BladeForums.com 2024 Traditional Knife is available! Price is $250 ea (shipped within CONUS).
Order here: https://www.bladeforums.com/help/2024-traditional/
High Temperature Quenchant
- Thread starter me2
- Start date
- Joined
- Oct 18, 2001
- Messages
- 20,978
any transmission fluid will work.
- Joined
- Dec 2, 1999
- Messages
- 9,910
Me2 Maybe Im not understanding your question. Do you want to quench your blades or heat your blades. I like "Tough quench" available from Brownells. It has a high flash point and is very consistant.
- Joined
- Jan 5, 2005
- Messages
- 2,531
Tough Quench here too ; Try it - you'll like it
Mark Williams
Moderator
- Joined
- Nov 28, 2000
- Messages
- 4,760
I think he might be looking at marquenching.
- Joined
- Dec 2, 1999
- Messages
- 9,910
I think so too. If so Nitre Blue from Brownells will do the job and other jobs as well but it is a salt. Nitre blue is very nice stuff though. It doesnt creep out of its container when stored instead it cools into a beartiful white hard block.
- Joined
- Oct 18, 2001
- Messages
- 20,978
I got my info from Ray Kirk...watched him marquench in tranny fluid at 375F. Said any brand would work.
Personally, I use Tough-Quench at 130-150F for regular quenching...but hope to set up another tank, similar to what Ray has, soon.
Personally, I use Tough-Quench at 130-150F for regular quenching...but hope to set up another tank, similar to what Ray has, soon.
- Joined
- Sep 9, 2003
- Messages
- 2,361
Me2, the biggest bit of information has been left out here, not to worry since it is the most commonly overlooked for being so critical. What steels do you plan to heat treat?
If it will be something like 1080, 1084, 1095, w1, w2 etc... forego the marquenching and use a good quenchant at 150F and interrupt the quench before it cools below 400F. (it is not that difficult and can be done very well with a little practice). These steels, which I referr to as shallow hardening as per tests such as the Jominy and others that measure the depth of hardening in a given steel in 1" diameters, do not repond well to any kind of high temperature quenchant, even salts, this image I posted not too long ago represents:
If a hobbiest level is your interest, marquenching will really not make that big of a difference in your product, it is one of those things that if you are serious you need to take the plunge and do it with the proper equipment. Short of that, interrupted quenching will work fine, even better with the steels mentioned above. I could only guess at what was in that steel pictured above before I got hardcore enough to buy the microscopes, and believe me metallography is more than what most pro smiths or makers should ever need unless they are downright neurotic about this stuff.
If it will be something like 1080, 1084, 1095, w1, w2 etc... forego the marquenching and use a good quenchant at 150F and interrupt the quench before it cools below 400F. (it is not that difficult and can be done very well with a little practice). These steels, which I referr to as shallow hardening as per tests such as the Jominy and others that measure the depth of hardening in a given steel in 1" diameters, do not repond well to any kind of high temperature quenchant, even salts, this image I posted not too long ago represents:
If a hobbiest level is your interest, marquenching will really not make that big of a difference in your product, it is one of those things that if you are serious you need to take the plunge and do it with the proper equipment. Short of that, interrupted quenching will work fine, even better with the steels mentioned above. I could only guess at what was in that steel pictured above before I got hardcore enough to buy the microscopes, and believe me metallography is more than what most pro smiths or makers should ever need unless they are downright neurotic about this stuff.
- Joined
- Sep 9, 2003
- Messages
- 2,361
This is what that steel above should look like if you nail it:
I would like to take this time to wholeheartedly apologize to folks for my annoying assumption that everybody is some kind of nerd stuck at 400magnification and above, I do realize that most of you have a life. I post images of blobs without any explaination. I could also see how it could appear like I am a kid showing a new toy to anybody I can, the fact is that it is the best tool I have found to clearly cut through the confusion of all the techno-babble I have been spouting all these years. I think it is nice to have such images made by a knifemaker, on knifemaking steel, in a knifemaking shop, instead of in a book written by some guy in a distant lab, that has never met a knifemaker (on a campus where knives are most likely banned ).
I would like to take this time to wholeheartedly apologize to folks for my annoying assumption that everybody is some kind of nerd stuck at 400magnification and above, I do realize that most of you have a life. I post images of blobs without any explaination. I could also see how it could appear like I am a kid showing a new toy to anybody I can, the fact is that it is the best tool I have found to clearly cut through the confusion of all the techno-babble I have been spouting all these years. I think it is nice to have such images made by a knifemaker, on knifemaking steel, in a knifemaking shop, instead of in a book written by some guy in a distant lab, that has never met a knifemaker (on a campus where knives are most likely banned
).
I wanted to stay below the flash point to avoid starting a fire when dropping a red hot blade into the oil. I am trying to quench from austenizing temp to Ms for 1095 and W-1 (or whatever files are made from) and hold for lower bainite, or mostly bainite. A little martensite wont hurt. Kevin, what is that in the first 2 pics? I have my guess, having done some metallography, but go ahead and tell me so I know for my own sake if I'm right. Daniel, what does Ray Kirk do afterward? Does he hold it at that temp?
I know the flash point and the point where the entire bucket of oil just catches on fire are different, but I dont want to be anywhere near the latter. This is all just a test really, just to see if it works. I'm planning on some blades in the puuko style w/ normally quenched edges, maybe in water, but probably oil, just to keep my 3rd & 4th blades from tying themselves into knots like the first one did. Theres some lunatic (IMHO) building a deck from ironwood, so I got some scraps of that coming for handles on blades 3 and 4. Soon as it quits raining, we'll see what happens.
I know the flash point and the point where the entire bucket of oil just catches on fire are different, but I dont want to be anywhere near the latter. This is all just a test really, just to see if it works. I'm planning on some blades in the puuko style w/ normally quenched edges, maybe in water, but probably oil, just to keep my 3rd & 4th blades from tying themselves into knots like the first one did. Theres some lunatic (IMHO) building a deck from ironwood, so I got some scraps of that coming for handles on blades 3 and 4. Soon as it quits raining, we'll see what happens.
- Joined
- Sep 9, 2003
- Messages
- 2,361
fitzo said:
Thank you for your support Mike, another good reason for me to share this work is to overcome the misleading impressions that most of us get that things are working just fine, when folks suggest there may be room for improvement. I thought many of the common techniques used by smiths were working fine for me as well, and that those books and spec sheets didnt apply to knifemaking. Then I started looking much closer and found that those books actually did make sense, and what I had thought was good enough left a whole lot of room for improvement. E.g. the steel in the top image broke just like it was fully hardened and would skate a file. Many of my samples that have undesirable mixed microstructures actually pass most of the standard bladesmith tests with no problem, but they still could have been a lot better.
- Joined
- Sep 9, 2003
- Messages
- 2,361
John L said:
Martempering/Marquenching involves using a quenching medium that is above the Ms (martensite start- before the blade actually hardens) temp, which is around 400F-450F. The blade is quenched to the temp of the quenchant and allowed to stabilize to that temperature throughout, then it is allowed to air cool from there to room temp. Doing this prevents the thin edge from cooling faster than the spine and warping due to radical differences in expansion as martensite forms. But if you use a shallow hardening steel the 400F+ quench may not have the cooling ability to keep some fine pearlite from forming at around 1000F, which is what you see in the first image.
Interrupted quenching may be what industry would describe as a timed quench. The blade is quenched into 150F. quenchant, which is fast enough to beat the pearlite formation, and then the blade, is removed from the oil before it drops below 400F. and allowed to air cool. The disadvantages are that you dont have the precise control and complete equalization that you would get from martempering, but we are dealing with pretty simple cross sections in knife blades. Also you need to get good at judging things as close to 400F as possible, because if you interrupt too soon you can precipitate upper bainite (not as tough as lower) and the edge could cool below Ms before the spine cools enough not to reheat the edge to a undesirable temperature when the cooling is removed, thus auto-tempering the fresh martensite at a temperature you may not want. It can be done with great success it just is not as fool proof as the salt set up with deeper hardening steel.
- Joined
- Sep 9, 2003
- Messages
- 2,361
me2 said:
The top images are martensite surrounded by fine pearlite that precipitated out that the grain boundaries because the quench just couldn't outpace its formation.
- Joined
- Jan 5, 2005
- Messages
- 2,531
here , hear fitzo - I 2nd that motion - Yes Kevin , Mete ; I eat this stuff for breakfast
Matthew Gregory
Chief Executive in charge of Entertainment
- Joined
- Jan 12, 2005
- Messages
- 6,573
I agree as well, but that simply means I'm as big a geek for this stuff as you are -- of course, I'm neither as qualified or as equipped to be the level of geek that you may be Kevin, but it's certainly something to shoot for! 
Anyway, please keep up the posts you two, many of us are paying attention!
Anyway, please keep up the posts you two, many of us are paying attention!
Well, wrong again. I figured it was martensite w/ retained austentite. That 135 oil quench 1095 looks great though. Any background on the samples you show, like thickness and grain size before quench? I'd be doing very thin sections, 3/32" at most, and the edge will be thinner, hopefully no less than 1/32" before quenching, if I get the grinding right. I'd hate to have that issue the other fella here had w/ 1095. I can fix a twisted tip, but the other pics were heartbreaking. I'll have to check my literature again, but I'm pretty sure that 100% lower bainite is theoretically possible up to 1/8" or so. Of course, thats no guarantee I'll get it. As an aside, Daniel that sub-hilt kukri is outstanding.
- Joined
- Sep 9, 2003
- Messages
- 2,361
OIC now I have to rethink your question, 3/32 does indeed make a big difference, the smallest of information can really change the parameters, not that cross section is a small detail. At that thin of cross section the salts may work. Oil may as well but you will still have the vapor point and flash issues. Most of my test samples are to help me with my quality control on my blades which range in thickness from 1/8 to slightly over ¼. I never did enjoy making a fillet knife.
In 3/16 to ¼ samples I have tried just about every variation I can think of in salts to get rid of that fine pearlite, different soak temps, times, agitation, prior microstructure from spheroidized to martensitic, larger grains, smaller grains in the batch that is pictured I tried both pearlitic and martensitic samples. I had heard that lower austenitizing temps could do the trick, but not for me so far. I keep trying because it would be great to be able to use my salts for all of my work, but after all my searching I still keep a tank of #50 oil to suit my needs.
In 3/16 to ¼ samples I have tried just about every variation I can think of in salts to get rid of that fine pearlite, different soak temps, times, agitation, prior microstructure from spheroidized to martensitic, larger grains, smaller grains in the batch that is pictured I tried both pearlitic and martensitic samples. I had heard that lower austenitizing temps could do the trick, but not for me so far. I keep trying because it would be great to be able to use my salts for all of my work, but after all my searching I still keep a tank of #50 oil to suit my needs.