Cpm 3v heat treating need help

L

Larry H.

Joined
Aug 3, 2020
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I recently finished up a knife made of cpm 3v. First time ever using the material, and the knife came out softer than a file. So let me explain the conditions.

The steel was previously annealed by some company so it was soft. After grinding my knife to my template I took it to my heat treat oven and set it to 1975 give or take 25 deg. Waited for it to get there and then put my knife in and let it soak for 20 min. At the 20 min mark pulled the knife out put it in my vise with one 1/2” aluminum plate and one 2” aluminum plate that were both cold from the freezer, tightened the vise and cooled to room temp (would say it might have taken 30 seconds to cool). Pulled it out and the file bit decently. So I through it back in the 1975 oven and did the same exact thing but with compressed air to cool it faster (thought that was the cause) guess it wasn’t because it’s still soft! ☹️

So if any body has any thoughts or comments please let me know cause all I can think is let it soak longer or higher heat.
 
No figured from what I had read of people forging this some times and getting success that it would be alright. Besides that from the two times I did it I had very little decarb, so figured it was alright.
 
Larry H. said:
No figured from what I had read of people forging this some times and getting success that it would be alright. Besides that from the two times I did it I had very little decarb, so figured it was alright.
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Nah, you need to protect from decarb.

You need to use stainless steel foil and fold into a envelope.

Grind decarb off before checking with a file.
It will harden just fine at 1975°f
+/- 25°f sounds like a bummer. A lot can change in 25°f
 
decarb is the key but also not going to get the max out of the steel withought at least a dry ice treatment post quench (i like to do it withought snap temper)
my 3v HT runs foil wrapped in kiln 1500 5 min 2000f 20 min plate quench LN soak over night then 2x temper 400 2 hours each 61-62 rc
 
Well I guess my next question is there any way to get the hardness that I need without the foil and cryo, or is anybody that has done 3v doing a knife and wouldn’t mind throughing this one in and heat treating it.
 
We heat treat 3V all the time.

my other question is where did the steel come from. You said it was annealed by someone else but it should come from the factory annealed.
 
Larry H. said:
Well I guess my next question is there any way to get the hardness that I need without the foil and cryo, or is anybody that has done 3v doing a knife and wouldn’t mind throughing this one in and heat treating it.
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Without foil and cryo pick a different steel.
 
To JTknives the steel came from an ebay seller that said it had came from an Edm shop and that it was a cut off.
 
Thought about the foil just didn’t want to mess with something that I hadn’t done, but guess I already have with choosing a steel I’ve never messed with.
 
Larry H. said:
To JTknives the steel came from an ebay seller that said it had came from an Edm shop and that it was a cut off.
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I would be real carful buying eBay steel in any form. I have had countless customers send me knives made from eBay Steel that just would not harden at all. Granted this is generally flat bars being listed as 1084, 1085, 1095, 5160 exc but really just mild steel. I am always suspicious of “drops” as I am a machinist and know how drops are handled. Generally a drop is considered scrap and should be marked. In the real world generally it’s not as it’s just tossed in the scrap bin. Then someone will dig one out and ask “any one remember what alloy this was”. “Oh I think that was xyz, ok thanks”. So just be careful on what you spend your hard earned money on. If it’s a drop from a round bar and it’s clearly still got the factory marking on the end that’s different.
 
Hey Im also a machinist. But anyways this steel was marked 3v with a marker and looked to have been cut on all surfaces by a saw. He also had a bunch of other steel for sale, pretty sure the post may still be up.

Is it ok to email you on your site? I’m new and don’t want to break the rules.
 
Yeah send me an email.

Some shops are religious in marking steel. One shop I worked in had to because we made parts for the government and everything had to be marked 100% of the time. If you cut something off a bar you had to make sure you transferred the alloy, heat lot number and any other information onto the bar or chunk before cutting. If you cut the marked area off the bar and did not mark the remaining bar your ass was given a good whooping. Thy could no longer use it because thy could not prove that steel is what you said it was. Where I work now all we use for round stock is 1144 and all our flat/square stock is mild. Sawmill’s are not to picky on alloy as long as it’s metal and is not warn out lol.
 
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