S30V questions (Cliff Stamp u r welcome to post)

I agree with Tom & Jerry (;) on the heat treat and specific differences. There is no "best". Specialization is just that. Is a Ferrari better than a John Deere?

In steel, all is in constance flux and balance. add in one and lose some in the other (harder may lose toughness in a trade for abrasion resistance).

As Jery mentioned, the integrity of the "name" of the maker tells you more. Wild claims are often not true anyway.

On the CATRA in our lab, S30V excels in abrasion resistance (edge retention). one point in Rc makes less difference than the angle and geometry of the edge. "Q" fog testing shows (us) that BG-42 is better than S30V in corrosion resistance. Both are excellent steels....just different.

One is a powdered metal, the other a VIM VAR ingot steel. One cost more than the other. One is more difficult to heat treat than the other.

Curious, If you buy a good knife from a reputable maker, you are getting your money's worth.

sal
 
I say Amen to Sal's comments. Of course take my sustainment with a grain of salt because it comes from someone that still loves G-2.
 
Originally posted by Sal Glesser
On the CATRA in our lab, S30V excels in abrasion resistance (edge retention). one point in Rc makes less difference than the angle and geometry of the edge.

sal
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Not surprising, but I very much appreciate an observation that comes from pretty darned repeatable test apparatus.
Originally posted by Sal Glesser
"Q" fog testing shows (us) that BG-42 is better than S30V in corrosion resistance. Both are excellent steels....just different.
sal
Click to expand...
I do not doubt Sal's findings at all... but this is a bit surprising, and interesting, given Crucible's claims. Again, interesting since the Q Fog is ostensibly a repeatable test. (although heat treat can affect corrosion resistance also).

Sal, what does the Q Fog test involve? Salt spray?
 
Originally posted by Klaus
... I very much wondered about some strong statements against this steel for which I found no real-world basis at all.

In this thread a lot of knowleadable people gave some very good input about their S30V experience and as expected all very positive ones.

Klaus
Click to expand...

And therein lies the forum reader's imperative... you must take what you read in light of the poster's background, experience, and track record for accuracy and insight. No shortcuts. Hang around and listen and learn, and filter in and out. Look for the open minded, not the obviously dogmatic. Look for the true trend, the "signal" amongst the "noise".

When Sal and Jerry share their observations (and there are others), you soak it up. Same with Phil Wilson, RJ Martin, Kit Carson, and a good number of others.

End of rant. Out.
 
Question for Sal, have you found it very difficult to treat S30V, and how do you check for consistancy? Do you check every 20 or something and if so how? Do you use a Rc checker or similar?

How many blades do you do at a time?

With regards to BG42 and S30V I am extacicly happy with my BG42 blades in my Chris Reeve knives, the very thought that S30V could be even *say* only 5% better interests me as I have been so happy with BG42 any improvement is a genuine surprise and a nice one at that.

GREAT thread BTW, I am actually understanding 90% of this thread!:eek:
 
Hi General. The difficulty in heat treating S30V is in the equipment necessary and the close temperature controls necessary. With the right equipment, which most heat treaters have, it is controllable. The problem is in trying to heat treat oneself without sophisticated equipment. that's why the custom guys as well as the factories send out heat treat to heat treat professionals such as Paul Boss.

We Rc everything. At least one test in every several hundred pieces. I would imagine that most custom and factories alike do the same.

sal
 
He can't, we won't let him... :)

Actually, Paul has an understudy who is doing a lot of the work on his own. His name is also Paul. I mean let's face it. Paul Bos is from Southern California; people are born retired there... :D

BTW, Paul Bos Rockwells EVERY blade he heat treats at least twice, once after hardening then again after tempering. If it's not right on, he does it all again.
 
Sal I hope you are not implying that a custom maker cann't properly heat treat S30V himself. Personally I believe makers can heat treat just as well as P. Bos and maybe even better in some cases. I am no way an x-spert on this subject, and I had thought one of the benifits of S30 was it was easier to treat than some of the other CPM steels.
 
Hi RDangerer. "Q"-fog is a salt spray with chemicals added to speed up the process. They keep very accurate measurement of the amount of corrosion at specified intervals. We generally use 6 hours, 12 hours and 24 hours. If it's going to rust, it will within the 24 hour period. We selected "Q"-fog because it is a government accepted and approved system, and is very consistant.

Hi Db. It maybe possible for custom makers to heat treat their own blades, but with S30V it is more difficult that other steels. We have not successfully heat treated S30V in our own shop. Strange things happen. As we get better heat treating equpipment for our prototype shop, we'll keep S30V in mind. Right now we use a conventional electric heat treating oven.

sal
 
DB, saying "Personally I believe makers can heat treat just as well as P. Bos and maybe even better in some cases", would be like me saying "Personally I believe Paul Bos can make knives just as well as knifemakers and maybe even better in some cases." He has over a million dollars in his equipment. Precision, atmoshperically controlled ovens and Inconel retorts are VERY expensive. Paul has been heat treating knives longer than most knifemakers have been making them. His expertise is respected by Crucible Steel company with whom he consulted directly to work out the ideal schedule for S30V, along with quite a few knifemakers who tested the results. It is easy to heat treat S30V or most any other steel for that matter. It is NOT easy to do it well. Very few knifemakers even own a Rockwell tester, so very few who do their own heat treating know exactly what they are getting, except by field testing and trying to control their process as well as they can. Most heat treating ovens costing under $1000 are precise to about +/- 50F. Some have added thermocouples to resort to manual control to improve that, but that's about as good as you can do. Without atmospheric control, it's necessary to use tool wrap to keep the blade from decarburizing. Tool wrap insulates the blade, and prevents it from cooling quickly after it comes out of the oven. Some makers use quench plates to speed cooling. That doesn't work very well with tapered tangs and fully ground blades. Atmospherically controlled ovens and retorts, where you can harden under Argon to prevent decarburization, then after hardening evacuate the chamber by pulling a vacuum and repurge with a blast of cold Argon is better, since the thinnest parts of the blade (the part that cuts) cools fastest. Most makers don't have liquid nitrogen dewars and resort to dry ice; that's ok but not as efficient as LN2. +/- 50F is not at all accurate enough for tempering. Etc., etc.

S30V might be easier to heat treat because it can be effectively hardened under 2000F, whereas some CPM steels need to go above that and most smaller/less expensive ovens can't do that. That doesn't mean that the heat treating process is less critical.

One last thing, Paul Bos has without any question the most demanding quality control program used in this or any industry. Me, and about a hundred other totally unforgiving knifemakers who use his services! :)
 
I heat treat S30 V with a manually controlled ecectric oven. I have worked out my foil wrapping so that I can get it off very fast, then do an interrupted oil quench. The blades are still orange when they go into the oil. It takes constant attention and a concerted effort, but to me this is a part of the process that gives me satisfaction when it comes out right. In talking to Bruce DiPalma and in a query to Crucible answered by a metallurgist named Chris Love, I was told that this method was fine for S30V heat treat.
I have to take them to a machine shop to test the HRC, so do not do it on every blade. I do spot checks. The lowest test run on any of these blades was a 58 and the highest a 60. The 58 was one reading out of three on a batch of five larger than usual blades that I had targeted at 59 (the other two were 59). My more normal sized blades are in the 3" to 4 1/2" by 1" to 1 1/4" range and I attempt to reach 61, but have not tested higher than 60 and average in the 59-60 range. The machine shop only gives me whole numbers for HRC.
I think I can see a slight difference in the grindability between the two, but it may be all in my head. There doesn't seem to be any difference in edge holding.
 
I never meant to imply that the heat treating process is less critical for S30V, or any steel for that matter.. Jerry just because you can't heat treat it well, or are unwilling to do it doesn't mean others can't heat treat it properly. I do respect Mr. Bos and what he can do, and has done. But don't try and tell me he is the only one who can heat treat worth a damn, that's just bs, Their are allot of custom makers who believe that the heat treat is one of the most important parts of making a knife and take that step very seriously and do it very well.
 
Hi Shgeo. Maybe I can pick your brain on your process. We failed at our attempt. I'm sure, as Jerry mentioned, the "Operator" is critical here.

BTW, Spyderco will CATRA test any blade for any custom knifemaker, factory or foundry. This information can be used to test your own work.

We will provide the Rc (on our Rockwell tester), edge angle (from our Goniometer), a cut by cut (in mm) numerical list and a graph of the cutting curve (from the CATRA). We charge $25 for the service. We do the foundries at no charge as this gives us early information. We can also sharpen it for you to whatever angle you prefer prior to the test.

Two basic rules apply: We both keep the information confidential and you cannot use our information for commercial purposes (we are not an accredited agency and we don't want the job. We do it to help our industry create better products).

We will also break a lock or blade. Provide a graph of the break and a graph showing the rating in Spyderco's lock strength parameters. Again, these are "in-house" standards only and the information cannot be made public or used in advertising. The purpose is for a maker or factory to have a convenient and inexpensive way to get consistent information from the same equipment and source. The fee for this is also $25. Barry, our lab tech handles the testing and test pieces should go to him.


sal
 
Well DB, I don't think I said Paul was the only person who could do it well. I explained why I said what I said. I choose not to do my own heat treating, even though I have pretty much the same equipment as most knifemakers who do, because I can't do it as well as he does. There are probably plenty of talented knifemakers who are a lot smarter and more gifted than I am, who can. I do know there are a lot of talented knifemakers who are both smarter and more gifted than me who can't. We talk about that all the time. This thing isn't black and white, it's a fuzzy gray.
 
There is a difference between good and best!

I send my knives to Paul.


The specialized stainless boxes he hangs the blades in before he sticks them in his furnace cost WAY more than one of those hobby heat treat ovens that many people place their faith in. And if you dont rockwell EVERY SINGLE KNIFE you are not testing your product properly.
 
A very interesting thread.

Another question on S30V:

How hard is the SV30 stock as it is shipped from the factory? I keep hearing that the material is hard to work, is this because it is harder then normal, can it be annealed, or is it the Vanadium content?

Perhaps there is some intermediate step that can be taken to make SV-30 easier to work, without detrement to the final product.

n2s

edited to add:
We often discuss the RC of the final product, but is there a standard RC level for factory steel stock?
 
I am strictly small time as far as quantity goes. I heat treat 4 to 5 blades from one 36" bar at one time. I heat to 2000 F. This take my little oven about 3 1/2 hours to achieve.
I wrap them in a sheet of white paper and fold the foil around them so that I can get it off as fast as possible.
I quickly open the oven door and get one blade out and close it again so that the oven temp stays high.
This is labor/attention intensive and I would not want to attempt it on larger batches of blades.
 
S30V is just a bit hard to grind, but it's a major pain in the butt to finish after grinding - for me anyway. The combination of the vanadium and the chromium likely causes this IMO. It loads (clogs) belts quickly when grinding, and the finishing is difficult because it just seems to hang onto those last few scratches like it owns them. It typically takes me about 50% longer to bring an S30V blade to a high finish compared to one in 154CM.

All steel is shipped annealed with an Rc usually in the low 30's. That's not really the problem.
 
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