Which quenchant?

G

gudspelr

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Jul 1, 2013
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I’m setting up new quench tanks and am branching out. I invested in some Parks 50 a while back and have used it with pretty good results. Although, I understand some steels would do better with a slower speed oil and now that I’m going to have two containers, I’m looking for another quenchant. So my question is, which oil would you suggest? I use a salt pot for austenizing and the steels I’ve used/may likely use in the future include:
15n20
1080
80crv2
5160
52100

There may be others I try in the future, but figured that might give some of you an idea for suggestions. Thanks in advance for the help.

Jeremy
 
Parks AAA. Only downside to that is its gotta be heated just like canola oil. McMaster carr has some 11 sec oil thats some people seem to reallu like as well.
 
For 15n20 and 1080 you can stick with the parks. The others will harden just fine in parks but you may get less stress/distortion in a slower oil without compromising hardness. Any medium speed quench oil should work fine.

I would recommend grabbing the heat treat app. Anything that says water/brine quench you can sub parks 50 for. Anything that says oil quench use a medium speed oil. If you want to quench air/plate quenching steels in oil, pick something very slow.

May not be perfect in all cases, for that you will have to look at TTT diagrams, but this should get you close. TTT curves should let you figure out pretty easily how long you have, and you can then do the math based on the thickness of the steel vs the cooling curve provided by the MFR.

If that sounds like a pain (and it is), just look at the TTT diagram, see if falls into the slow, medium or fast category, roughly speaking, quench in what seems appropriate, check hardness and use a faster quenchant if you didn't get the results you were looking for. Otherwise, you get into calculus (integrals) and thermo (thermal conductivity). If you are dead set on doing the math, and you don't mind cheating a bit (the thermal conductivity of steel doesn't change that much over a few hundred degrees F) you can just use about 30-40 W/MK for everything and be safe. Ultimately, what you will find is that to do the math well, it takes a good bit of gonkulating. And the look-it-up then try-it-and-see method probably takes less time.
 
Thanks for the suggestions. As far as doing math, figuring calculations, and anything else along those lines...I’m probably not gonna be that guy. From my feeble understanding, I get that steels which don’t need the faster quenchant to beat the curve for hardening could do well with a slower oil because of less stress...I think. I know I’ve heard/read some folks like some medium speed oils-I just haven’t really had any experience with them. Thus the thread :).


Jeremy
 
Get AAA for sure. It’s great oil and if you set up your quench time like I did mine with a pid and heater then with a flip of a switch the tank comes on and holds temp.
 
I feel kinda high maintenance for asking this...is there a medium speed oil that would work well and not need to be heated and held at temperature? If it’s really cold in the shop, I get bringing oil up to a reasonable temp, but would rather not have to worry about getting to a specific temperature and holding it there-if there’s a different choice that works well, that is. I don’t want to come off as wanting to cut corners or having a quenchant that isn’t good...

Jeremy
 
I dont know of any but I have not looked. The reasion we use AAA is because for the most part it’s the best oil for the slow steels we use. There are other oils out there but most professional oils like AAA can not bought by average joes. I remember when AAA was that way. You would call up a distributor and thywould tell you to take a hike, in notso many words. It’s worth heating it be audits the best.
 
Other than Parks 50, I am not aware of an oil that is designed to be used at room temperature. That being said, I have only used a few. Maybe. I doubt there are many. It seems a somewhat ubiquitous requirement.

What JT describes is a good idea and should be relatively easy to make with a simple heating element, TC, and PID. If you weld, I might weld up a vertical quench tank and heat it with a hot plate switched by a PID. Secure it all well in some sort of enclosure to prevent spillage.

Even cooler would be making a setup like a Sous Vide immersion circulator. PID, heating element and TC with some sort of circulating pump. Would require some more experimentation, but would guarantee an even temp throughout the oil.

How did you do yours JT?
 
I use a 10 dollar camper hot plate, and a deep fryer thermometer.
If you want to avoid doing this then just stick with faster quench steels. As long as you have a way to properly maintain a temp you should be good to go
 
I will snap a pic of it tomarow when I’m in the shop. It’s absalutly nothing fancy. The fanciest thing about it is that it’s connected to a remote access outlet so I can turn it on from anywhere i have phone or internet signal. Funny how often I use this. It allows me to turn it on and let it heat up without even having to be home so it’s warm when I need it. Yeah mine is a pid, ssr, npt threaded heating element and a tc.
 
Thanks again for all the info, I’ll have to check out the AAA. Sounds like you’ve got a pretty cool setup, JT.

Jeremy
 
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