1084 heat treat help

J

Jbw1118

New Member
I have two bars of 1084 that I purchased from nj steel baron about 4 years ago. in the past week I made three knives out of one of the bars. Friend of mine came over today and brought his Rockwell tester. All three of the knives were not hard. Reading in the 30’s. I have an evenheat oven and I had heat treated all of them at 1475 for 10 minutes and quenched in canola oil heated to about 120. And tempered at 375 twice for two hours each. We proceeded to heat treat these knives 3 more times today. With varying soak times from 1 minute, 5 minutes and twenty minutes. We checked them as we were pulling them out to make sure they were non magnetic and to no avail we couldn’t get them to harden. Checked with a file and it would dig in. Also checked the rockwell tester with the calibrated test coupon that came with it and it was reading dead on.

Last thing we did was cut two test coupons, one from each bar and heat treated them. No luck.

Any help would be appreciated.

Thanks
Jason
 
I would try annealing your stock first. There have been reports of older stock from NJSB not being fully annealed.
 
Where on the blades did you test?

Did you do any grinding/clean up prior to testing?

Those are two of the standard troubleshooting questions.
 
Were any thermal treatments of any sort done to the steel prior to austenitizing/quenching?

Have you actually verified your oven accuracy?

Personally, I'd ditch canola oil for 1084 but it might not be the main culprit.
 
Sounds like you might have some 1018. I don't see how a simple steel like 1084 could be so tied up in spheroidized knots as to not respond to multiple attempts at hardening. I may be wrong, So see if you can normalize at 1600, etc, but it is sounding a tad suspicious.
 
I also have some 1084 from a few years ago from NJSB. I had areas that were hard but also very soft areas. From 40's - 60's Rockwell. I ended up doing the normalization process they recommend on their website and now I get consistent results. Its a PITA doing this extra cycle but necessary
 
Never had a problem with NJSB 1084, but I forge it, so it gets normalized and all that. #1 thing I would do right off the bat is spark test a sample on the grinder. It’s pretty easy to tell if it’s mild steel. If it is high carbon, then I would quench a sample at 1600 or so. If that gets hard, but your blades didn’t, then your temp on your oven might be suspect. If that doesn’t harden at 1600, then try it in water. If the sample hardens in water, then your quenchant might be the problem. That should narrow it down.
 
Now, I must qualify anything that I might have said. The 18 1.5 x .25 x 48 sticks of NJSB 1084 that I have left from the first batch that he had smelted is apparently a different steel than the current lots. The latest stuff tests out at .82 carbon with no vanadium according to the specs on the website. The stuff I have tested out at like .87 with like .015 V intentionally added IRC. That was the stuff that you sometimes saw referred to as 1084FG that tested out like what they call 1086M but on the low end of the V scale. Supposedly, the 1 inch Schrade surplus stuff is plain 1094, but very clean and with fairly high manganese.
 
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