Corrosion comparision question

Bill Siegle

Bill Siegle

Knifemaker / Craftsman / Service Provider
Joined
Oct 3, 2000
Messages
6,817
I know CPM3V is not stainless but is it closer to being non stainless like D2 or more suseptable to corrosion like O1? Anyone have any knowledge of this? I am asking because I really like 3V but I was thinking of doing a couple with blasted finishes. If the corrosion resistance were close to D2, I don't think I'd have too many concerns about blasting. Any assistence would be appreciated. Thanks :)
 
Bill,

I would venture a guess that CPM 3V is closer to D2 in corosion resistance than it would be to 0-1. 3V has 7.5% chromium and if memory serves me, I think D2 has around 11% chromium and O-1 has around 1%. I'm not sure how much good the 7.5% will do in regards to corosion resistance when industry dictates 13 or 14% minimum to be considered stainless or stain-resistant. Here is a link to Crucible's data sheets on all of thier products. I hope it is of help to you. Good luck and have fun!

http://www.crucibleservice.com/datash.cfm

Rick
 
As a knife steel D2 is considered a semi-stainless steel. At 12% C it will typically discolor but not rust. The 7.5% C of CPM doesn't do much at all for corrosion resistance. It should corrode more like O1 than D2.
 
Mete,

At what point does the chromium (percentage wise) start to affect corrosion resistance? Based on the numbers 7.5% (V3) is closer to 12%(D2) than it is .6%(O-1), so my thinking was that V3 would be approx. 12.5 times more corrosion resistant than O-1.

Rick
 
It's not as easy as all that. The original definition for stainless steel was at least 12 % chromium.At the 12% point in knives it's 'semi-stainless' because some of the chromium is tied up as carbides.Therefore you see typically 14-16 % chromium for 'stainless' knives.Cpm 3V has vanadium and molybdenum which has stronger affinity for carbon than chromium so some of the chromium will do some work for corrosion resistance..How much is a question. It's not developed for corrosion resistance and Crucible makes no mention of it so you'd have to do some tests.
 
When 3V rusts it rusts in a bad way. That's the biggest drawback to an otherwise outstanding steel. I am ordering a big Fehrman/Hood in 3V but a coated version for that reason.
 
Bill,
I've blasted 3V with ceramic bead and in a wet environment, it picked up lots of rust spots. With glass bead, it would be worse.

On D2, I bought a bunch of it from Crucible several years back that is 12.50% chrome and I have blasted it with no signs of rust.

Keep in mind that the ceramic bead peens the finish and glass bead cuts it.

For what it's worth, I've satin finished 3V to 400 grit and it didn't do any better than ceramic bead.
 
To me 3V acts like A2, it wont rust just looking at it like 01, but if you get some pitting it goes pretty deep pretty fast.. But the stuff is tough.
 
Thanks guys :) Sounds like as long as I treat it like it is any other high carbon I should be fine. Not too much of an issue as I do a lot of 5160 blades. Just looking to branch out a little into some of the "latest and greatest". I like the good press 3V is getting. I really like building the big blades and getting toughness and edgeholding without too much "give" for the "take" seems like a win win :D
 
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