Cpm d2

B

Bear_Blade

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Jun 9, 2009
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I was wondering if anyone had the oppertunity to use CPM D2 in a kitchen knife application. I am looking to build along traditional Japanese lines, for example a sashimi knife or a similar long chisel ground edge. I was going to use O1, and a supplier recomended CPM D2 for consideration.

My biggest concearns are edge holding, ability to work well at RC 59-61, that being little chance of chipping or breaking. And during the heat treat, if the edge is thinner than 0.020" is there a significant chance of warping or the edge "waveing".

Any insight is appreciated.
 
I thoguht I heard somewhere that CPM-D2 is slightly less corrosion resistant than regular D2. For a kitchen knife that might be a big concern. I've never had a CPM-D2 knife though, only D2, so hopefully someone who has had both can chime in on this.
 
Nope. The CPM D2 seems to be more corrosion resistant than standard ingot D2, at least judging by mine.

It was my understanding that the CPM D2 that Spyderco used for a Sprint Run each of Military and Paramilitary was from a single experimental batch that Crucible made to test processes. From what I read, they felt the gains were too small to make the process profitable and weren't going to make any more. That could have changed later, or it may change after the bankruptcy/sale and restart.

Apart from that, I can't help other than to say if you can find some useable bar stock, buy it. ;)
 
I think that CPMD2 would be great in a kitchen knife.

I used it in one of my knives (one of the only ones that isn't a kitchen knife), and I really like it. It easily takes a good, refined edge. The edge was .017" before heat treating, but the grind was relatively thick (.25" FFG); no warping issues. Heat treat was performed by Paul Bos to 60-61 HRC. I use this knife as my shop knife (hard use) and the edge shows no chipping issues. Edge angle is 30-degrees inclusive.

The only time I saw any corrosion was when my bedroom flooded, and I used the knife to cut up soggy carpet. It developed small spots (easily cleaned) of corrosion when set down on the carpet for a few hours.
 
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My experience with CPM D-2 is that it's fairly resistant to chipping. My composite blade Kershaw JYDII has had all sorts of contact with metal objects, and suffered virtually no chipping. The CPM D-2 Spyderco Military I used to have did chip a little on contact with steel, though Spyderco runs their steel harder than Kershaw (and uses thinner edge geometry).
IIRC Spyderco aims for the 60-62 Rc range, so 59-61 should be just about right if you want a little more toughness.
 
Anyone know how hard Kershaw runs their CPM-D2? The composite Leek I have have seems very hard. It is at least as hard as their S30V IMO. The Tyrade composite doesn't seem to have quite the edge holding even with the thicker edge, it is about 40 deg. Could be I just can't get it as sharp with the thicker edge. The Leek has been re-profiled down to below 30 deg. and is a wonderful cuter.
 
CPMD2 would make a great kitchen knife @ 60/62 HRc. Edge holding will be very good and edge chipping will not be an issue. CPMD2 should not be troublesome when heat treating - Paul Bos or Peters Heat Treating can handle the heat treat although alot of custom makers Heat treat in their own shops with no problems. Corrosion resistance of CPMD2 is noticeably better than conventional D2.
 
Yoshikane makes kitchen knives from SKD-11 which is the same D2 steel, just name is Japanese standard. They take it all the way up to 64HRC and as far as I can tell a lot of people are very happy with them.

I've seen reports on microchipping here and there, although some stated that it went away after first or second sharpening.
On the other hand, 64HRC steel, with relatively thin edge, 15 per side or less, if you aren't careful you can definitely chip it.
Well, if you use it as a typical western knife and western knife user then chances are you'll break it too.
 
Question: how do expect D2 to hold without staining when cutting more agressive foods, like onion? My D2 Para seems sensitive to staining if I'm not careful with maintenance. And there is no way the wife would alow me to start oiling the kitchen knives, no matter what.:D
 
I use a D2 paring knife and have never had a problem with staining.Of course you could get a better steel - CPM 154 !
 
Cisco Kid said:
Question: how do expect D2 to hold without staining when cutting more agressive foods, like onion?
Click to expand...
Rinse and wipe frequently during food prep. And D2 is semi stainless which is the easiest case. Try maintaining O1 or any other carbon steels in the kitchen, and you'll see how easy D2 is.
Anyway, I can maintain all of my carbon steel kitchen knives rust/stain and even patina free. No oiling. Just don't let the knife stay wet for long time, I mean even during food prep. As soon as you stop using it wipe it dry with a cloth or paper towel, after acidic stuff rinse and wipe. And of course, once you are done wash and dry thoroughly, by hand.

The only thing that I couldn't really maintain w/o discoloration is the wrought iron cladding on my Shigefusa kitaeji knives. That this starts turning yellow while approaching the ingredients, at least that's the feeling I get.
 
I'd be happier if someone looked into something less traditional.

Knife industry is stuck in early/mid 20th century steels and a few are even older than that. I was watching the show the other day about metals and one of the interesting points was that in car industry majority of the steel and other alloys didn't even exist 10(!) years ago.

How many new steels appeared in knives in last 10 years? S30V, ZDP-189 and Cowry-X, 110V. S35VN is nowhere to be seen...
 
My Spyderco Military in CPM D2 is 62 RC as tested by Phil Wilson and has no issues with chipping at all with an edge at about 10 per side. I run a tiny microbevel sometimes at 15 per side, but right now I have it at 10 per side (the actual edge is probably 12 per side due to natural convexing from freehanding) and it cuts through everything I throw at it without chipping and with better edge retention than S30V. I think it would make an excellent kitchen knife at 62-63 RC, if not harder. The CPM process allows the steel to be more corrosion resistance and have better toughness, allowing you to run it a couple points harder than ingot D2 with similar toughness to the softer standard D2 from my understanding. I am a big fan of CPM D2. However, my favorite kitchen knife is a Takeda Gyuto in Super Blue steel at 64 RC. It is paper thin, not very tough or corrosion resistant, but it will take a great edge, hold it forever, and it's ultra thin geometry makes it by far the best cutting kitchen knife I've ever used. If you are used to banging around Wustofs you won't like the Takeda, but to me it is worth the extra effort to keep it stain free and avoiding bones, as it cuts so effortlessly it is just a joy to use. Sorry for the thread drift, but when I think of kitchen knives the greatness of my Takeda always comes to mind.

Mike
 
Thanks for the great feedback you guys, that does help quite a bit. Personally, CPM D2 may not be the first choice in materials for a Japanese "styled" knife, but if we all stuck with traditional materials, knife making would still be flint or obsidian. CPM D2 might not offer much if any improvement, but the discussion here, might help it to be recognised as a kitchen knife steel.
 
Hey guys, I found this little blurb you might find interesting. It isn"t CPM D2 but should be close.

D2 is sometimes called a "semi-stainless". It has a fairly high chrome content (12%), but not high enough to classify it as stainless. It is more stain resistant than the plain carbon steels. It has good wear resistance. D2 is much tougher than the premium stainless steels like ATS-34, but not as tough as many of the other non-stainless steels mentioned here. The combination of great wear resistance, almost-stainlessness, and good toughness make it a great choice for a number of knife styles. Bob Dozier is one maker who uses D2. Benchmade is using D2 in its knives, both fixed and folders. Japanese equivalent SKD-11 is used by Yoshikane in their kitchen knives.

Thanks Gator, I beleive you touched on this.
 
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I completely agree with you about sticking to traditionals ;)
And yeah, that sounds like a note from the steel charts I work on. BTW, I just realized I have 2 different records for CPM D2 and D2. Probably I should combine them, since it's just a CPM version of it.
 
The only similarity between conventional D2 and CPMD2 is the analysis. Everything else changes - improves due to the CPM process.
 
I don't argue that. But the chart is about chemical composition, although it has a column for the technology used for the steel and that's where they differ. I'd assume it is cleaner alloy too.
Although, knowing Crucible I wouldn't be surprised if CPM D2 has something added to it, to improve performance.
 
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