View Full Version : D-2 Verses S30V

Jim Burke
03-18-2003, 12:34 AM
I make primarily survival and utility blades and was wondering which of these steels was better for durability and for stain resistance. Also I have found that Mcmastercar carries D-2 precision ground at a very good price. Would the D-2 ordered from them be the same quality as from admiral or crucible.

Thanks, Jim Burke.

Jerry Hossom
03-18-2003, 07:48 AM
S30V is definitely superior to D2 in most every way - toughness, edge holding, and stain resistance.

D2 is D2. Sometimes there are small variations in the Chromium content, but that is usually marked D2-modified. I have sometimes noticed some variation in the graininess of D2 and that may be due to Chromium content, but performance seemed the same in all cases. It's a good steel, but not up to S30V in performance. It will rust BTW, despite 12% chrome.

Jim Burke
03-18-2003, 03:46 PM
I have used ats-34 primarily up till now. Would D-2 be superior to the ATS-34.

Thanks, Jim.

Jerry Hossom
03-18-2003, 11:30 PM
D2 will hold an edge longer than ATS-34 for sure. It isn't as stainless though. Toughness is probably about the same, given proper heat treating.

Jason Cutter
03-20-2003, 07:45 PM
I haven't worked with S30V yet (note I said, yet) but I understood it was a steel designed specifically for knife blades. It looks to have some similarities with D-2 like the carbon content, but I think the similarities end there. And it looks to be a "real" stainless steel with about 17% chrome.

The advantage of D-2 is accessibility - I think that if you can get your hands on precision ground D-2 at a reasonable price, you've got a great thing going. Aside from price, I personally think it holds a tremendous edge when HT-ed properly, possibly much better than it has been given credit for in the past.

My experience with the people I make working knives for, has been that these folks are "serious" hunters, who often like or will tolerate carbon steel (1095, O-1) and its required maintenance for what they feel is improved usability in the field. Many of them have tried some D-2 knives I made when my HT-er started doing what I thought was a better HT method and they report a noticable improvement in edge holding. But you really need 60-61HRC on D-2 which is the sweet spot for edge holding.

In terms of stainlessness and edge holding- 440C has about 16-17% chromium, ATS-34 has 14% chromium, D-2 has 12% chromium. So the stain-resistance goes down in that order, 440C being the best at stain resistance. But edge holding - well, its the other way around, D-2 is the best.

Without labouring the point - both steels D2 and S30V are great steels, in the end yopu probably need to give them a go to check out whether it "does it" for you (and your customers).

Hope this rambling makes sense. Cheers. Jason.

03-22-2003, 11:08 AM
I use both of these steels almost exclusively. I've been using D2 since I first tried it three years ago (I still have some 440C and one piece if ATS 34 laying around from before). I just started using S30V last summer. The S30V is definately superior for the final product, although it is noticably more difficult to cut and grind.
I have gotten better results from the D2 lately by doing a very fast oil quench followed by sub-zero treatment as soon as it reaches ambient temperature. This is followed by triple tempering at 400 F for smaller blades and at 450 F for large blades. The purpose of this is to keep the grain size a small as possible. It doesn't develop orange peel texture nearly as easily as with my old method where I snap-tempered before the sub-zero quench.
No matter what I do, though I can't get the D2 to get as fine an edge as the S30V. S30V will get sharp enough to slice loosely held paper towel (slowly).

Gary Mulkey
03-24-2003, 09:24 AM

Since I use both of these steels, you got my attention with your D2 H/T. I'm curious as to why you chose to use an oil quench for D2. How did the hardness vary from the typical air quench?


03-24-2003, 03:03 PM
I started the oil quench dor a couple of reasons, One, it doesn't get the scale build up from air contact. Primarily though it was to quench as fast as possible in order to reduce grain size, especially of carbides.
The larger embedded grains are in the matrix of any material, the easier it is to initiate cracking. I was trying to maximize strength and also to reduce the orange peel effect. I don't think D2 gets any harder this way. but it does noticably have a finer-grained orange peel texture when I screw up and polish too much.
I harden about 1975 F and quench to room temp within 15 seconds or so, and then immediately put the blades on dry ice for several hours.
I don't think that much time is necessary. The martensite transition is temperature dependent and the time shouldn't matter. Somehow it always seems to be late in the evening, so I just leave it overnight.

Gary Mulkey
03-24-2003, 07:15 PM

Most specs say that your about 100 degrees high on the critical for D2. I normally use 1850. I wonder how that effects it. However, "If it ain't broke, don't fix it."


03-24-2003, 07:46 PM
Sorry, I meant to type 1875 F, I was on my way back to work and in a hurry. They just don't make these keys big enough. Half the time I hit two at a time and often the wrong one prints.
Also I should mention that I do an interupted oil quench, that I finish of in tap water, then the freezing. I suspend the blades in the oil until it stops smoking and boiling.
I use Turco solution from K&G to coat the blades for the heat treat. This allows me to just move the blades a couple of feet to a large jug of oil. I take them out one at a time and they don't even have time to change color before hitting the oil.
I got the idea after doing some carbon damascus the called for an oil quench. The specs on the D2 (from Bolher/Uddeholm) listed oil quenching as one recommended method and it evolved from there.

Gary Mulkey
03-25-2003, 09:06 AM

I haven't used the Turco because I thought it was only good to around 1500 degrees. I assume that you have no problems with it at 1875? Are you getting any scale or blackening of the D2 during H/T & quench?


03-25-2003, 02:34 PM
I use the Turco up to 2000 F with S30V-or pretty close to it, my heat treat oven is 120 V and takes 3 to 4 hrs to get to 2000 F. The blades come out without scale. The coating turns gray sort of like old Carbon steel patina, but it comes of easily. I generally use a blue 120 belt to get rid of it, tnen scotch brite etc. I've got some cork belts coming that I going to try out.

03-25-2003, 04:26 PM
What kind of oven are you using? What would be a good oven to start with that wont cost an arm and a leg?

03-25-2003, 06:44 PM
I got my oven from a jewelry supply place in Kirtland, NM. They sell them for burn out ovens for casting for $550.00. It has a 10" X 9" X 6" chamber, is fire brick lined in a SS housing with manual controls, pyrometer, thermocouple and rheostat. It is 1440 Watt, 120 V. They claim it will get 2000 F in 2 hrs and 2200 F max, however I get 2000 F in about 4 hrs on mine and that is as high as i have gotten it to go. It works for me though as S30V is the highest temperature hardening stuff I work with. I usually get antsy and stop it about 1980 these days-it seems to work well at that temp.
The only real difference I see with the thousand dollar models the supply houses sell is the lack of digital control. What the hell, it gives me something to keep me out of the bars on Friday evening.
I bought a separate thermometer and calibrated my cookstove oven and now use it to temper. It keeps an even temp at the lower end that is hard to do with the manually controlled oven.
I can give you their website address if you want. I'm not sure if I am supposed to post those kind of things here though.

Jerry Hossom
03-25-2003, 07:52 PM
Go ahead and post it Steve. It's always OK to provide supplier information. It benefits all of us.

BTW, Crucible Steel recommends that D2 be tempered once before cryo, followed by one or two more temper cycles. Have you ever tried a snap temper before cryo?

03-25-2003, 08:30 PM
Thanks Jerry.
This is 550 Supply in Kidtland, NM. Agoogle search will turn them up, too. The oven is listed under casting equipment and supplies.
They are also a good source of sheet metals: brass, nickle silver, sterling silver and copper. Also good for conchos and other findings if you use them.
In Albuquerque, New Mexico Clays, pottery supply and Rio Grande Supply for jewelry also have ovens and other things that are fun to spend money on...

Jerry, I have tried the snap temoer method on some D2 and found that I got a lot coarser carbides, based on the size of pits in some I overpolished to the orange peel state. I believe this is caused by plucking carbide crystals off the surface when you polish too long. With the immediate sub-zero0 treatment this texture seems to be quite a but finer-grained. I have also experimented with a second sub-zero quench after the first temper.

I strongly etched some D2 with muriatic at ,375N (full strength) and the carbide/ matrix texture shows up really well after about 20 minutes in summer temperatures. It makes a kind of neat wootz like pattern, although entirely random.

Jerry Hossom
03-25-2003, 08:49 PM
The Rio Grande Supply catalogs are my favorite bathroom reading material. Great mind food, the catalogs that is... :)

Even using the same HT (back when I did my own and used D2), I found a great deal of variation in D2 from various sources. Some was fairly fine grained and almost took a polish, some was very grainy. Since I was pretty careful with my HT schedule, I don't think I was entirely responsible for the variances. It all seemed to be a good using steel, but it was not fun trying to give it a presentable finish. All of it would orange peel if you pushed it with much of a polish.

03-27-2003, 01:43 PM
I recently emailed with Crucible as I am staring a project in S30V...while browsing their site I found variuos info on the cromecontent and ask them....they said it has 10.5%

now that does not really sound stainresistant in my book as I know D2 will rust...but is it the Vanadium that help here?? (4%)

03-27-2003, 03:21 PM
The Crucible website lists S30V at:
C, 1.45%
Cr, 14.0%
V, 4.0%
Mo, 2.0%
I am not aware of any of their steels in the 10% Cr range.

Jerry Hossom
03-27-2003, 04:13 PM
Jens, are you speaking of S30V? It is 14% chrome, if I remember correctly, but the 10.5% number might be "free" chromium which is actually what protects steel from corrosion. Because of powder metallurgy and the lower level of carbon, S30V is VERY stainless.

Jason Cutter
03-27-2003, 05:37 PM
10.5% chrome in S30V is not right. It is as you said - the free chrome after carbide formation is accounted for. I must say that some of the information can be tricky, especially for those of us not inclined towards chemistry (like me).

The batch variation in grain size and the Wootz pattern is a "problem" I've encountered too. But I've found it happens in not only D-2 but also some batches of 440C and ATS-34 also. I have a 440C blade I made recently from an errant batch (old), HT with the same cryo, triple temper and tested at 59HRC and it looks almost like fine cable damascus !! Nothing wrong with edge holding except that it definitely wasn't as fine - ripping sharp though.

Like many others I have heard that that grain structure is to do with the chrome content - I have no idea what that means !

I guess one possibility is that like all steels there are individual manufacturer and mill variations - my batch of "D-2" says that it has Tungsten (W) in it as well. No other steel info says that Tungsten is a standard component. Likewise with my O-1 from Sheffield, England - says it has 0.5% Vanadium, 0.5% Tungsten - many other batches I have used have only one or the other, not both.

I suppose on that point, all D-2 may not be just D-2, but S30V is only made by Crucible, so the components of S30V SHOULD be more consistent and predictable.

Does that make sense ? (It did to me last night !) Cheers. Jason.

03-27-2003, 06:08 PM
An anology that might be made to illuminate the grain size discussion for differences in the same alloy, is that of the difference between granite, rhyolite and obsidian. All three of these rocks have the same composition. The only difference is in the cooling rates.
Granite cools slowly and forms large crystals that weather rapidly, so that it weathers and erodes relatively swiftly.
Rhyolite is the volcanic equivalent, that cools rapidly forming a fine-grained rock that is much tougher and more wear resistant.
Obsidian is a volcanic form that quenches so rapdily it has no chance to fully crystallize, forming glass.
The only one suitable for chipping into knives and stone points is the obsidian.
This is why I started the fast quenching of D2. I figured if I could limit the size of carbide growth during the Martensite transition, it might make a tougher final product.
So far, the fast quench seems to work on the size limiting of carbides judging from the coarseness differences of orange peel texture between different heat treating methods. I will have more to say on this later as I find out more. I guess I need to do some destructive testing, which is hard for me to do on something I have made.

03-28-2003, 03:05 AM
Ya I thought it had to be wrong as on several places they state it to have 14%.....

The 10.5% was listed in the diagram called "Carbidetype and volumen" ....but the numbers for the other steels did not make sence I guess your right Jerry about it being "free" chromium

03-29-2003, 11:33 PM
I want to update my previous posts on the turco heat treat coating. It has worked very well on D2 up close to 1900 F. I hardened some S30V this evening at a full 2000 F and the coating broke down. There is mucho scale on five blades of S30V.

I thought I had done S30V with Turco before, but on checking back, I realize that I hadn't. I hope I haven't caused anyone to lose some S30V.

I am snap tempering them now and will try to clean them up, but am not optimistic. Oh well, live and learn.
Just to be sure, I will go back to foil on the S30V in the future.