CPM 3V PROBLEMS

[jmccustomknives]

After about 12 years of tinkering with carbon steels I decided to dive in to the CPM world.  I figured the 3V alloy would make a most excellent rough use knife so I purchased a stick.  I made a knife via stock removal, and heat treated it per the manufactures specifications.  My heat treat oven has two thermocouples, one analogue one electric with a pid.  After the plate quench and temper cycles per the specifications I went to clean up the blade.  It felt soft so I decided to try it on a brass rod.  The rod won, the steel folded like a cheap dress.  I took a little test piece and through it into my forge which was heating, brought it up to a yellow heat and let it air cool.  It was still soft enough for a file to bite.  Repeated the test, this time I water quenched the piece.  It hardened, so I snapped it.  The grain was very course, borderline burned steel sized.  

I took the test blade and reprofiled to repair the damage then heat treated as I would a simple carbon steel.  It hardened.  

The steel reminded me of L-6 which I'd purchased from the same, well known supplier. so I took a piece of each and did a comparative spark test.  

If I didn't know better I got a stick of L-6, but what do you guys think?  The pics are the two pieces.  

If any of you guys have any experience I'd greatly appreciate any input.  

The third is just a recent bowie I forged up, just for reference.

[rhitee93]

I've not used 3V, but have dabbled with S35VN recently with decent results.  The data sheets look similar in process, although the temps are different.

What temp did you decide to quench from?  What temper temp did you use?

 

[ThomasPowers]

Seems like every pro blade maker has a story about a mislabeled steel buy; have you contacted the vendor?

[jmccustomknives]

11 hours ago, rhitee93 said:

I've not used 3V, but have dabbled with S35VN recently with decent results.  The data sheets look similar in process, although the temps are different.

What temp did you decide to quench from?  What temper temp did you use? 

 I shot for the middle, 1950F with the 1000F temper.  Supposed to net 60 RCH

11 hours ago, ThomasPowers said:

Seems like every pro blade maker has a story about a mislabeled steel buy; have you contacted the vendor?

Yes, I might have to get on to him at Batsons.  lol

[rhitee93]

Wow, had to go back and look at the 3V datasheet again.  That stuff tempers much higher than S35VN.

Based on what you have said, I can't help but wonder if you are right about it being a lower alloy steel.  Does it rust if you leave a drop of water on it overnight?

[jmccustomknives]

4 hours ago, rhitee93 said:

Wow, had to go back and look at the 3V datasheet again.  That stuff tempers much higher than S35VN.

Based on what you have said, I can't help but wonder if you are right about it being a lower alloy steel.  Does it rust if you leave a drop of water on it overnight?

I haven't tried that yet.  It should rust, but have some resistance.  I'm assuming something like A-2.  I've got some D-series tool steels.  Going to try to anneal and re harden a piece.  If that works then I know it's the wrong stuff and not my equipment.  

[jmccustomknives]

Update:  I sent the steel off and had it tested.  It's definitely cpm 3v.  So even in failure I learned something.  1st thing, I'd never even considered that steels like these acutally have 2 hardening temperatures.  One for the iron carbides and one for the high alloy that are 400 deg apart.  It was also recommended that I do an interrupted quench instead of plates, so that's going to be fun.