Professional Heat Treatment

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AF

AF

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I sent a batch of knives to a professional service. CPM154. I requested foil and cryo. I don't know their quenching method.
One of the knives came back with the tip bent about 90 degrees like it was dropped on the floor. I figured I could grind it off but first I tried straigtening just by pushing into a table top.
To my surprise the tip straigthened.
Another knife had a slightly bend tip that I was able to easily straighten in the same manner.
Now I'm questioning whether these knives were properly hardened.
I heat treat my knives in 1084 and when they are warped they are much more difficult to straighten.
These knives have pin marks from an apparent rockwell test. The readings were not provided to me. I requested 60-61 rc.
I don't feel confident in these blades.
Any advice?
 
Bent 90 degrees and they sent it to you that way? No way a hardened tip should bend back that easily. There's a lot that sounds sketchy about this. Where did you get your steel? I hope not Ebay? Like HSC said, give them a call. Not sure if this knife is for sale or not but I know I wouldn't be comfortable selling it.

As noted above, try the file test but I wouldn't use this place again. Go to JT, he's very active here and from what I've seen, tries damn hard to make sure his customers are happy.
 
I emailed them yesterday morning. Haven't heard back. I'll try calling.
A file bites into the spine. It bites into the edge too but not as aggresively. On a 1084 knife that I made, the file skates on the spine.
I bought the steel from Alpha Knife Supply.
 
AF said:
I emailed them yesterday morning. Haven't heard back. I'll try calling.
A file bites into the spine. It bites into the edge too but not as aggresively. On a 1084 knife that I made, the file skates on the spine.
I bought the steel from Alpha Knife Supply.
Click to expand...

is there another knifemaker near you with a rockwell tester? I would suspect bad heat treat.
 
If your worried about the hardness you can send them to us and we will hardness test them for you. Won’t charge you anything Just ask you to cover the return shipping.

On a side note that almost sounds like a lack of cryo or sub zero treatment. It would be dang hard to temper cpm154 down to a point where you could easily bend the point back straight. That’s assuming a proper heat treat to begin width. That’s under 40-50hrc if your able to plastic deform a blade that much and not snap it. How much of the tip are we talking about and where the edge bevels ground first or was it just a profiled blank. I always recommend heat treating flat blanks. It keeps a lot if this funky ness at bay.
 
Oh I meant to ask, are the blades at all discolored? A softer spine then the edge on an air hardening steel could point to using a torch to straighten the blade. This softens the spine and if not carful the heat will bleed down into the edge and soften that area. If it was torch straightened thy could of over heated the tip and that’s why it’s easy to bend. I am quite opposed to using a torch on a blade that’s properly heat treated. We don’t torch straighten here. We use surface peening to straighten any bowed blades here. It leave a light dimpled surface that’s easily removed when finishing as the dimples are around .001-.003 deep. We are considering investing in a bead blaster to speed up the process.
 
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Thanks for the reply JTknives JTknives . Based on what you said I'm wondering if these were straightened with a torch. Perhaps they were rockwell tested before the torch? I'm speculating.
I'm attaching a couple photos. You can see the coloring of the blades. In the spine pic, the blade with the badly bent tip that I straightened is second from the bottom. It was just the final 1/4" that was bent. It must have been dropped or banged into something when hot. It is quite thin.
These knives are definitely not hardened like I wanted. Perhaps I was asking for something unreasonable because these knives are ground just the way I do with 1084.
I have a simple shop and I use files quite a bit. I don't grind after heat treat. On these I did taper the tangs on a 4X36 with a ceramic belt.
I appreciate your offer to rockwell test them. I think I will send to you if you think you can heat treat them properly.
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So is that coloring on the blades indicative of a torch? Or just normal for an oven? It's not something I'm accustomed to when heat treating 1084 in a homemade forge.
 
JTknives said:
We use surface peening to straighten any bowed blades here. It leave a light dimpled surface that’s easily removed when finishing as the dimples are around .001-.003 deep. We are considering investing in a bead blaster to speed up the process.
Click to expand...

I've tried beadblasting and it works until you grind the beadblast off if you want it satin finished then it's bowed again. but with the peening you mention, it doesn't go back bowed after you grind it out?
 
No, that's not from a torch.

When you heat treat with blades wrapped in stainless ht foil and quench between plates that's what the steel looks like as quenched when you open the foil up.

The temperatures are higher with stainless/higher alloy steels and the soak times are longer so the steel needs to be protected from oxygen at high temperature to prevent decarburizing.


If they were black and crusty with scale due to a bad foil seal, it would not be good considering the times and temps needed to hit those kinds of steels.

Grind thin before HT on thinner stock and you can expect some warping.

I recommend communication with the person who heat treated them. Just as H HSC /// said.

AF said:
So is that coloring on the blades indicative of a torch? Or just normal for an oven? It's not something I'm accustomed to when heat treating 1084 in a homemade forge.
Click to expand...
 
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I got good news and bad news. Good news is I got your blades and thy have been hardness tester. Bad news is thy are a bit soft. From my experience with CPM-154 it’s quite hard to get it under 60 with a proper heat treat and cold treatment. Only way to get lower is to crank the tempering heat up to 600°f+ But that would visibly discolor the blade from the heat. I will let the picture speak for its self.
 
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Thanks Jarod. I figured they had to be but I really appreciate you confirming that with actual testing.
 
To me it looks like it did not get a subzero treatment. Then again I have never tried cpm-154 without a subzero treatment but I have played with aebl trying to convert the retained austenite with a handful of short low temp tempers. The results are similar to what your blades show. Thy got hard but not as hard as if thy where sub zero treated. Another funny thing with these types of steel is thy don’t become ridged first awhile after the quench and sub zero treatment. I have tried this with aebl. Pulled a blade from Liquid nitrogen and let it warm up and I could still bend it by hand. It takes a good tempering cycle(s) to really stiffen some of these alloys up. I really wish I knew what heat treat process trugrit uses.
 
Jeff didn't return my calls. I spoke with Tru Grit and they said they would refund my money but first were going to speak with Jeff.
Obviously this opens up a lot of questions about Jeff's heat treatment and Rockwell testing.
EDITED TO ADD:
Tru Grit refunded me.
 
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