View Full Version : More Quench ?'s
01-22-2011, 01:19 PM
I've learned that hardening steel requires more than 'heat it and toss in water barrel'.
I have a .30 ammo can full of canola oil, it holds just about a gallon. I want to install a 110V water heater element and t'stat to get the oil to proper heat for quench. Is the volume enough or do I need a bigger tank? And, what temperatures should it be for 1095 and 01?
Thanks from me and all the friends and family getting my blades. :)
01-22-2011, 03:07 PM
For temperature, 120 to 130F should be adequate for canola, vegetable, or other similar oils.
I think 1 gallon of oil should be plenty of volume for a quench tank, but I can't speak directly to the effectiveness of the thermostat. If it's a surface mounted stat that relies on the temperature of the metal can to reach a certain degree, chances are you'll have to set it lower than the temp you want the oil to get to, as the oil is going to heat up PROBABLY a lot faster than the metal it's encased in. I could be wrong, but you'll probably have to play with it a little bit.
02-10-2011, 07:52 AM
There is probably a better way but I just heat my oil in a cheap 2 1/2 gal pot from the dollar store on a cheap table top electric burner. I keep meaning to get a thermometer but I have just been testing the temp with my finger. So far it has worked for me.
02-10-2011, 12:29 PM
Get yourself a candy thermometer from the grocery store, they are a enclosed glass tube with a thermometer gauge inside and a metal clip to hang on your quench tank. Pretty cheap and seem to be accurate ! That's what I use anyway.
02-10-2011, 02:53 PM
This might sound confusing... you need an amount of oil that when a blade is being quenched, does not exceed 180F. For the types of oils mentioned, anything above 180F and the steel will not fully harden.
When asked, I generally recommend a quench tank that will hold 2+ gallons (mine holds 3 1/2 gals). That way you can quench more than one blade at a time without the oil exceeding the 180F threshold. Otherwise if quenching multiple blades, you often have to wait for the oil to cool down before quenching subsequent blades.
I just finished quenching 6 Damascus, and 6 1084 blades (all "hunter" sized), and the oil temp maxed out at 115F. (that was Parks 50). OOPS! Should be about time to get them into the tempering oven! :)
02-18-2011, 03:35 PM
I'm still having trouble getting my steel hard. I can't seem to get the file to skip after hardening but I can still file on it pretty easy. Once or twice I found areas of a blade that didn't want to file but not the complete blade. I'm using warmed canola and soaking the metal in the oven for 15-20 minutes. Time from the oven door being opened till the steel is completely submerged is less than 5 seconds, point first and moving it around in the oil. Temperature using Aldos 1095 is 1525* and I tried 1550, I built a PID controlled oven and verified the temperature with a FLUKE meter and thermocouple. Normalized three times prior to heat treating. The one time I was successful I used the forge, heated to just past magnetic and tossed it in a half frozen bucket of water. It snapped really good. :) Any secret hint's besides trying Goddards 'Goop'.
02-18-2011, 06:49 PM
I think that the time that it takes to get the steel into the quenchant is your problem. It must still be at critical temperature when it enters the quenchant and then cool quicklly to miss the nose of the cooling curve on the ITT diagram. I have my quench tank close enough to my forge that all I have to do is turn and take no more than one step. I probably go from forge to quench tank in less than two seconds. The 1095 is a shallow hardening steel and it takes less than a second for it to start forming pearlite and it is even more essential that it still be at critical temperature when it hits the quenchant. There are not a lot of alloy carbides in 1095, it doesn't need to be soaked for 15-20 minutes; about a minute should get the carbon back into solution. Also, what temperature were you soaking at and was it in an electric oven or the gas forge?
02-18-2011, 07:36 PM
With 1095 you don't need to exceed 1450 degrees to harden.
I heat mine down around 1425 degrees and even down to 1410 when chasing a hamon. Normalise twice and cool to black heat then final heat and dunk. I've never had a soft blade using this method. Keep your quench tank within a arms stretch anywhere around you so you're not having to stroll around with the iron.
02-20-2011, 09:02 PM
Thanks, I've been using an electric oven and heating it to 1525, too much heat hu? I went back to basics, forge and magnet. I built a sort of brick wall oven in front of the forge so I could heat the steel and watch the color at the same time and get it out easily when I wanted. I watched it get hot and kept moving it a bit to heat it evenly, I was also able to tilt the blade as necessary to evenly heat the whole blade. Every once in awhile I moved it out enough to check it with a magnet. I also put the quench tank on the anvil next to the forge so it would be close. When it went non-magnet it went right in the oil (canola @ 120*) but only the blade half. I ended up with a very hard blade edge and a soft spine. I did that three times then three cycles of tempering (350*). It worked very well. Now if I can get the same results again I might have learned something. I used Goddards brass rod trick to check for blade hardness and temper and got excellent results. Thanks again for all the help.
02-21-2011, 12:42 PM
If you have a kiln, I would stick with that. Also, I think you probably need to pick between using canola oil or 1095. If you choose canola, heat to 120-130 deg. and make O-1 your steel of choice for it. I heat mine to 1500 deg., soak for about 10 minutes and then quench in the warmed canola oil. I consistantly get 63+- 1 rhc out of the quench.
If you choose 1095 for your steel, I have found that canola just won't do it. I couldn't get out of the low 50's rhc using it. I ordered some of the McMaster Carr 11 sec and that helped quite a bit, but I only use it for my 1095/15N20 Damascus. I gave up using straight 1095 steel. If you plan on using 1095, you might even look at ordering the highly recommended Parks 50.
The other very important factor is quenching as quickly as you can (within reason). Five seconds is way too long going into the quench. If you aren't trying to get your blade out of a foil packet, then you should be able to get it in there within 1-2 seconds. If you are using a foil packet, then we need to reconsider the method in which you are using. Once you put the blade in the oil, slice the oil with the blade right away to improve cooling effectiveness.
02-21-2011, 09:03 PM
Ok, with a shallow hardening steel like 1095 you will get a hard edge and soft spine with good grain control. 1095 is a shallow hardening steel and fine grain, which is what you want, decreases hardenability so you will only get martinsite formed to twice the depth of hardening. Where the blade is thicker than that you will have pearlite form. There will not be a jacket of martinsetic steel around a core of pearletic steel as with a steel rod. I personally don't feel that 1525 degrees is too high. The booklet of ITT diagrams from US Steel lists the austinization temp for their testing at 1625 degrees. You just don't have to do a real long soak the way you had been doing. Cementite goes into solution at a relatively low temperature. People were using oil, don't ask me which kind, at the Mad Dwarf hammer-in with Aldo's 1095 and were getting good results, so really I think you're fine on that along with the fact that you are getting a hard edge.
On the brass rod test. I've not had that much luck with it. I had a big chopper, a seax with a 13" blade, pass the brass rod test but had the edge roll over when I tried to chop a 4X4 with it. There are others who don't think much of the test either. What I do is try to chop through some soft iron wire with it; something like bailing wire. I just put the edge down on the wire and strike the spine with a mallet. If it chips, it's too hard. If the edge folds over, then it's too soft. I do accept a very slight indent on the edge where it is the thinnest. I also do some 2X4 chopping to see how the edge holds up. You could also get some fiberous roap and see how many times the blade cuts through it with a single draw or push cut.
1410 is below non-magnetic. Hamons don't make a knife. A good HT does. First off, forget 1095 unless you want to buy Parks #50, or chance a brine quench. Get 1080/84 and work with that. It will out perform poorly HTed 1095. 1095 does very well with a soak at between 1470°, and 1475° as a max. with a 5 to 10 minute soak at most. If you are going to use canola, warm it to 125°. And yes. 5 seconds to get it in the quench, is too long of time.
02-23-2011, 07:32 PM
I should qualify the the 1410 degrees.
I ramp up to 1450 degrees and turn down the oven until my pyro reads 1410. Since my blade is positioned in the top third of the oven and the pyro is in the lower third, I'm willing to bet the blade is still in the ballpark when removed from the oven. I don't do this to every blade but has worked in attaining hardness and a hamon.
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