Heat Treating 1084

nine9jack9

nine9jack9

Active Member
Never worked with 1084 before. Most of my experience has been with O1 and 15n20. My questions are: 1) in something like 1/8 stock, can I quench in oil or should I use brine?, 2) Is there enough manganese to through harden compared to something like O1? The last one is because I grin post heat treat to get away from issues of warpage. My research has shown that I should austenize at 1500F and temper at 400F for two hours. Tell me if there is anything wrong with this. Also, how long should I soak the steel at austenizing temps for? Thank you in advance for any help.
 
With 1/8", it should easily through harden. I would suggest a fast oil such as Parks #50, but Canola oil would probably do near as well with that steel. In my opinion, the slight extra benefit of brine is not worth the risk of losing a blade, but that is your call. I would not heat more than 1475°, with maybe a three to five minute soak, and two one hour tempers. If you find it too hard with 400° tempers, you can always temper again a bit higher.
 
if you are using 1084 from Aldo(njsteelbaron) you should have no issues thru hardening. put blade in a pre-heated 800C(about 1475F, easier to read on my thermometer)furnace, give it 2 or 3 minutes to heat thru, soak 3 to 5 minutes, then quench in Parks50 or another fast oil. once the blade is cool enough to touch bare handed, wipe excess oil off, rinse in cold water, 325F for one hour, ice water quench, then another hour in temper oven. 325F gave me Rc62-63, YMMV. good steel, but only a few sources and you are limited in dimensions available.
 
I did 2 small knives of 1084 on Saturday. The good thing about 1084 is that if you already HT something like 1095 or 0-1, it's easy as pie. I brought mine up to a dull cherry red, checked with a magnet, kept it at that temp for a few more minutes and quenched in peanut oil. I've seen several ABS master smiths do the exact same with they're knives. I tempered at 365 for 2 hours then 400 for 2 hours an had a nice straw color when done.
 
I don't know, I just always have. I heard it somewhere a long time ago and just have always done it like that.
 
You want to start with a slightly lower temper the first go around, then check the edge with a sharp new file. If it still skates across the edge because it's still too hard, then you want to increase the temperature a little more to temper the edge back some more to get a little more soft. If you start to feel some drag, then you might want to leave the temperature the same. If the file starts to eat into the edge, you might not want to do a second temper cycle at all. Always a good idea to make a few rough ground knife shape like objects (don't bother making them look pretty) and practice heat treating and doing some destructive tests when starting with a new type of steel. This would be my recommendation. You can learn a lot about the grain structure in your knife by locking it into a vise and bending it and/or breaking it.
 
Bending it will not tell you anything about the grain structure. Hardening and breaking will. Destructive testing is subjective as to the intended purpose of the knife in question. A knife intended for dressing an animal would not need to do more than cut well, and hold an edge well. The brass rod test on the edge is a reasonably good test for that. A survival type might require more resistance to abuse, but neither is going to do the others job as well as the original design intent of each. A second temper is almost always a bit more beneficial than a single, and does not change hardness if done at the same temp, but can assist in transforming any retained austenite into martensite, giving the blade a bit more strength. At worst, does no harm. Even slightly better if water quenched after each temper.
 
nine9jack9 said:
Never worked with 1084 before. Most of my experience has been with O1 and 15n20. My questions are: 1) in something like 1/8 stock, can I quench in oil or should I use brine?, 2) Is there enough manganese to through harden compared to something like O1? The last one is because I grin post heat treat to get away from issues of warpage. My research has shown that I should austenize at 1500F and temper at 400F for two hours. Tell me if there is anything wrong with this. Also, how long should I soak the steel at austenizing temps for? Thank you in advance for any help.
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if you add a couple of minutes between weighted quench plates, you should have no issue with warpage. annealed tool steel grinds a whole lot easier than steel at Rc60 or more. when working with a new steel, i would suggest making test mules(an old Car&Driver term for pre-production cars), 3 or 4 identical blades, temper one at 325F, one at 375F and so on then finish the blade and see which works the best for the knifes design. i have made several blades with 1084 that were tempered to Rc62-63 and i have had no isssues with the edge chipping or pitting.
 
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