What is the difference between these two steels?

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sharpmaker

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D2 and M2
I am asking because I am thinking about getting one of these knives when Ithe cash is available.

menchmade 710 M2
benchmade 806D2
 
D2 is a coarse grained, semi-rust resistant tool steel. M2 is a fine grained not-so rust resistant high speed tool steel. The high speed part isn't really important, that just means that it's suitable for cutting tools where the blade gets hot enough to soften other steels. M2 is a little tougher, but D2 has a better rep for edge holding. Neither is really suited for prying so the big factor is rust resistance and if you like highly polished edges, D2 and M2 respectively.
 
m2 is harder/holds edge better, but will rust faster. d2 is semi stainless and more brittle(i think)
 
Im not 100% sure but I think D2 has more chromium making it more corrosion resistant.
 
You guys who are guessing, who aren't metallurgists, and don't have the experience with lots of knives with each steel, are misleading yourselves. :D

Simply put, there are so many factors that go into how well a knife works, that the specific steel is not necessarily the most important of them. If you're comparing two knives identical except for the steel, that might have meaning -- the BM 710 in 154CM or M2. If you're comparing two different knives with the same steel, you could learn something, especially if they're from the same company.

With the two Benchmades in question, handle and blade shape are likely to be more important than which of two fairly sophisticated steels is marginally more appropriate, especially if the knife is intended for relatively light duty.
 
hey, those who complain that 440c isn't good enough wont notice anyways if you didn't tell em. on the m2, just keep some oil the the blade
 
You got that right. Most people never use a knife hard enough to tell.

I keep a bottle of food grade mineral oil on the kitchen counter. You can get it for a couple of bucks at the pharmacy. Rub a drop around on a blade now and again. Works fine, and you don't have to worry about poisoning yourself if you cut food with the knife.
 
Doens't Benchmade put the BK coating on all their M2 blades to counteract its inherent reduced corrosion resistance?
 
That's true Esav, quite frankly the actual "performance" difference of those two steels in this kind of knife is irrelevant, with the exception of corrosion resistance. Even then both knives are coated which eliminates much of that particular concern. Still, he asked what the differences were, and unless Benchmade really dropped the ball on the heat-treat then the previous posts were fairly accurate. Out of the two you mentioned though I'd probably go for the 806, I'm not a fan of the recurve on my 710, it cuts wonderfully, but I like sharpening on wide benchstones, which is difficult to do with the 710. Since both have axis locks now the 710's biggest advantage (to me) over the AFCK is gone, and hole-type openers beat thumbstuds any day of the week.
 
Those little bird and trout knives Gerber used to make(back when Gerber knives were good) were made out of M2, and they held an edge like a champ. In fact, you didn't wanna let them get too dull or chip, or you had yourself one heck of a time sharpening them. I would give the edge holding title to M2, but D2 is pretty close. D2 would be the more stain resistant of the two steels. Both make great blades when properly heat treated.
 
Danbo said:
I would give the edge holding title to M2, but D2 is pretty close.
Click to expand...
Not if M2 is optomized for edge retention. Most companies leave it fairly soft, in comparision to D2 the difference is fairly dramatic. You can put a set in production M2 blades as it is typically 6-8 HRC points under optimal. The difference in edge aggression will be determined by grit finish not steel. Both rust fairly easy, D2 pits much worse.

-Cliff
 
Cliff, I'm having a heck of a hard time understanding the first part of your last post. Why would M2 not be better at edge retention when optimized for edge retention? :confused: What does "You can put a set in production M2 blades as it is typically 6-8 HRC points under optimal.", mean?
 
Cliff means that if M2 is hardened optimally then D2 is not "pretty close" but markedly inferior, which makes sense. I know benchmade used to advertise their M2 blades at RC 64, not sure if they still do or not. I had issues with my edges microchipping when cutting through cardboard, that might have been due to the really thin edge I had put on that knife. I usually keep my stainless blades near to the factory edge so in that sense I've found them to be a bit more durable.
 
I thought, BM advertises M2 around 62HRC.

Staining isn´t an issue to me, so the only thing i have noticed so far is, that D2 turns in to a rough edge after a short time of using while M2 keeps it initial edge better.

Both work best on around 30°-36° edges.

As far as the two models go:

The main question: What are you going to do? What do you expect your knife to do?

The 806 features a thicker blade than the 710.
 
Cliff is right about the edge holding difference. I was only trying to be nice to the diehard D2 fanatics out there. ;) M2, properly heat treated for edge holding ability has a much higher Rockwell reading. M2 is also finer grained, which was already mentioned. I believe Wayne Goddard wrote that he has made some pure slicer knives out of M2 with great results.
 
You can get M2 up to 66 HRC, compare that to D2 at 58-62 HRC and the difference is obvious due to the hardness, plus M2 has greater wear resistance.

Most production companies however run it and D2 at the same hardness and thus the edge retention will be similar, however M2 is significantly more ductile so it will take a set where D2 will crack.

There may also be a difference seen if you cut materials like cardboard very fast, I have run trials on thin blades where the edge gets so hot it will readily burn skin on contact.

I keep meaning to run a thin M2 blade against say 1095 very fast and then very slow to see if there is a difference.

-Cliff
 
thanks alot guys, alot of what has been said was academic stuff that I tried to grasp but I am not quite sure I understand.
So basically, what you are saying guys is that it doesnt matter which of those steels I get for that type of folder?

Let me rephrase it for you: If I find the same folder for the same price for example, Which should I get? the M2 or the D2?
 
According to Crucible data sheets M2 is tougher and more wear resistant then D2.

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

Also as I understand, D2 have more carbon in it? which allows skilled bladesmith to play with internal carbides structures (like in bulat/wootz) and really make it perform.

As well as M2 -I think that this is really supersteel except corrosian resistance but because it is so strong it is hard to produce, so only BM making such knives but did not HT it to proper conditions - 64HRC (recommended by same Data sheets) simple because it require higher temperature in the owen etc. I try to make blade out of M2, miself but Paul Boss does not heat treat M2 (as well as CPM S90) - because it require to run owen at higher temperature.

Thanks, Vassili.
 
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