Forged S30V.......the testing begins

Ed Caffrey

Ed Caffrey

Joined
Jul 23, 1999
Messages
1,409
Well, Today I started carrying an EBK created from forged S30V. Once I got my hands on some heat treat foil (Thanks Bill!), I was able to try a few different methods of hardening. I found that the most complete hardening comes from placing the blade (while still in the foil) between two 1" plates of aluminum or steel. I tried tempering at 600F, but the blade would not pass the brass rod test. It appeard too soft........so the next one I tempered at 550F, and got good results,

So far, I really don't have too many great things to say about the S30V. It is super tough to finish in it's hardened state, is really difficult to sharpen in comparison to 52100, and the fact that it fully hardens means that I have to change my methodology about putting a knife together.

So far I have tested it on plywood and a heavy cardboard shipping tube, and done a little toughness testing between it, 1084, and 52100. The S30 is stout for it's thickness and geometry, but I'm so used to having blades that will bend to 90 degrees, that it really surprised me when the S30 blade let go with a lound SNAP, at about 30 degrees of flex.
S30 out performs 1084 as far as edge retention, and only slightly beats out 52100 on the plywood shaving. On the card board tube, it and the 52100 petered out at about the same time, but it only took a few strokes on the india stone to have the 52100 back to shaving sharp...........the S30 took considerably longer to bring the edge back.
I'll pack this S30 EBK around for a while, and let you know more. As of right now, the only advantage I can see in the S30 is the stain resistance for those who are really concerned about that sort of stuff. I was hoping that this steel would be the "Magic Arrow"........but I suppose I'll still be waiting for that one.
I do know that if I do decide to offer S30V on my EBKs and Progression folders, it will certainly not carry the same guaruntee that my other forged blades do......... either that, or I'll have to modify the blade thicknesses and geometry to help compensate for the weaknesses....... More to come.
 
Ed,

I have been playing a little with s30v also. Although I have not done the testing you have, I have found a recipie I like. My edges sharpen easily with stones so long as I do not grind the initial edge too thick before sharpening. I shoot for 12 to 15 mil before HT. No edge warpage yet. To see how I currently HT s30v do a search here for - CPM S30V HT sample. My last s30v blade with this recipie Rockwelled at 58 RC. I used forced air to quench. With your aluminum heat sinks you should beat that RC rating. EDIT: Never mind the search; here's a link to the thread: http://www.bladeforums.com/forums/showthread.php?s=&threadid=251958&highlight=s30v

Alhough I have tweeked the recipie it's foundation is based on advise given by Paul Bos, who had shared it with us here and gave it as a summury of sorts of experimentation by him and some others. There is one more tweek I want to make on my next HT. I want the second and third temper about 25 degrees F. lower than the first, thinking this may better preserve the RC of the first temper and yet obtain all the benefits of multiple tempers. I also want to rig up a faster air quench.

I like s30v but like you and others find it does not give up scrataches finer than about 800 or 1000 grit without an exhaustive fight.

Roger
 
Looks like you guys are taking it to the limit, but from what I have seen, the tests that Simonich put this stuff thru seem to back up the profile that Paul Bos is using. Just my two cents.:p
 
Ed,

Far be it from me to question your tests (In fact I'd love to switch to forging my S30V so I'm real interested in your tests!). I'm also sure you have the S30V data page. But there is some interesting things on there.

One is the hardening temp. 1900 and it behaves 'normal' where the tempering temps increase - the hardness lessens. However at 1950 and 2000, the hardness returns somewhat if you temper over 600 and 1000!?

That subtle behaviour change between 1900 and 1950 is really odd to me. You didn't mention your hardening temp, but that and cryo seem to be major factors in S30V.

Just food for thought.

Personally, I'd like forge, normalize, and send one off to Roger - if I can get all the stuff set up and Roger says OK.

Steve
 
Steve (Itrade),

All you got to do is let me know its on its way to me. It would be a great honor for me to HT a blade or blades for one of my teachers. The only thing you must know is: I will be on pins and needles and praying 'Lord please don't let me screw up', and I will let you grind the HT and temper discolorization off the blade. I will not touch your blade with a sanding belt. If that's okay with you let me know when its coming.

Roger
 
Kit, I was thinking the same thing when I read the title of the post. CPM's main advantage from what I understand is the very consistant grain structure from the powder technology. But then again I don't know anything about forging since all I do is stock removal.
 
Basically I forged the S30 just to see if it could be done successfully. You know us "Pounders".......gotta at least try to hit it with a hammer! :D

I have a stock removal blade that will be done this evening, and once it's finished, I'll throw it into the testing with the forged S30, and the 52100 to see how they compare. On the grain issue, I've already compared a forged cross section to the unforged bar.......there is a good deal of difference in the grain structure, with the forged S30 being noticably smaller....this surprised me, as I expected just the opposite to be true. As with most other steels, I just have to see for myself if all the things I've been told about this steel are true......... :)
 
Hey Ed-

Interesting stuff. I'm glad to hear you're playing and experimenting with this stuff.

What's your heat-treating method on it?

I really think this steel is done a great injustice if not ran through a very accurate heat source and allowed to soak at temperature.

I also think for fair comparisons it's important to have Rockwell's on the different test blades.

I know you're probably laughing at me and thinking, "Ah Nick, getting all technical on us...it's time for the barrel!" :)

But in all fairness, I really think the variables have to be cut down to a minimum. From the testing I've done on the S30 I sent to Paul, it's pretty fantastic stuff.

But of course I have to test it A LOT more too :)
Nick
 
With S30-V or any of the vanadium rich high alloy CPM steels, you arent going to get the best out of it unless you have very precise heat control. Wait, Nick just said that.

Ed, unlike you I dont like my knives to bend to easy, I like em stiff! :)
 
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