1084 heat treat help

The good news is that it takes your kiln a LOT less time to get from 1650 to 1400 and then to 1200 than it does from 1500 to tempering range.
 
I tried 1500 for 5 min with a quench in 120f oil. The sample hardened to about 30HRC and when hammered on it bent. I did go back and hammer harder on my test pieces. They all broke cleanly (oil and water quenched). I will try to cycle the steel down in temp as suggested. I have also sent out some emails to maufactures of different quench oils to see if any can be had in canada. If i find any i will post my findings.
 
Good advice from others here already. One other thing to check is the calibration of your hardness tester. I was getting very poor results from my 1084 (and other steels) following procedures that should work. I had tested my hardness tester when I got it and it was within a half point of the sample block. I never bumped the machine or had any reason to doubt its accuracy. So I thought my Parks 50 was worn out. I ordered a new batch and still poor results. Then I checked the tester again and it was way off. Who knows how it happened. After I calibrated it again results were back where I expected.
 
Thanks for your input. I just got the tester so that is what i thought as well but i have tested the test blocks before and after to ensure the unit is calibrated.
 
I have broke down and ordered some parks 50. I have yet to find the time to normalize and try the canola again. I will report back with my findings usings parks instead of canola.
 
Be aware when you test coupons, if they are small you are starting your quench through your tongs! A slow quench.
I have seen enough quench videos on youtube to notice that often people think they agitate, but actually they do it only in the second part of the quench, when the need for speed it's already expired!!
A water quench would allow you not agitate in the very first stage, but for quenching 10xx (even if 1084) into oil you should slice the hell of it since the very beginning of the quench...
 
Very good points. I believe i am not making these mistakes. I have increased the sample size to help with cooling. On a side note i tested some o1 steel. I heated to 1500f for 20 minutes and quenched in 130f oil. This hardens right up to 62.5 HRC in 3 seperate tests. From my research o1 is best quenched in parks AAA wich is slower than parks 50 (1084). The AAA is closer in speed to canola. I suspect the canola is a little to slow to fully harden the 1084. It does still harden and im pretty sure the edge gets close to full hardness. I have made some 1084 knives this way and they seem to perform well. Just my 2 cents. I will update when i try the parks 50 on my 1084. It is also possible my canola is slightly different than someone elses. I know someone said their 1084 was harndness tested in the 60s so obviously it works for someone.
 
I'm only using a atlas forge and canola and have never had much of a problem with 1084. The few times that I did it had to do with my oil temp. I have had large variation in temp from top to bottom especially after I harden a few blades . I have started to stir it briskly before I quench.
 
If it is highly spheroidized you need to go hotter with your initial cycle.
- 1650F-1700F
- 1525F
- 1475F, quench and grind the decarb off.

What stezan said about the tongs is really important. Better to have a long coupon at around 4" and don't test the half that the tongs held on to.

Stop water quenching... figure out your oil.
 
Thanks for your responses. I plan to normailize before i try the parks 50. I will also try a test piece not normalized in the parks to determine how much it is effecting my results. I give up on the water quench.
 
Quick update
I recieved my parks 50 oil. I normalized my steel as per the advice given. I then quenched and got a (65hrc). I had alot of decarb. I had to file pretty deep on the edge to get a file to skate. I then ground a section of the handle so i could perform a rockwell hardness test. I attribute the decarb to the steel spending so much time in the kiln. Initial heattreat was done from room temp. The second was not (12 minutes at each temp) but the whole process (including normalizing) meant the steel had alot of time at temp. No warp. I then tempered to 59hrc. I plan to heat treat my next blade without all the normalizing steps to see the difference in decarb and warpage. I have left all the edges pretty fat so hopefully its a non issue. Im not too sure the effect of the decarb if any on the final product. If it is an issue i will look into an antiscale. Thanks everyone for your help, i will continue to update my progress untill i have come to a reasonable conclusion. Hopefully someone will benefit from this.
 
If you are having big problems with decarb, I would suggest either leaving it pretty thick prior to heat treat or getting some toolwrap.
 
I just quenched 3 blades in the parks 50. I did not normalize them. All 3 came out at 65. I did have to grind pretty deep to get past the soft decarb layer. I attribute this to not using any antiscale. It seems like the same result i got when i went through a normalizing cycle. I have concluded that the steel is fine and that the canola oils i had were not fast enough to fully harden my 1084. Hopefully this helps someone. Even here in Canada the parks wasnt too expensive. I think to avoid the headaches it was worth it. If anyone has anything to add im all ears. Thanks to everyone for their contributions.
 
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