Why not S7 tool steel for blades...?

rfrink

rfrink

Joined
Aug 1, 2000
Messages
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I haven't seen anyone use S7 tool steel in blades....why?

A quick comparison to L6 and O1 seem to favor S7 for toughness at the same hardness.

At 55-57 Rc hard, S7 is nearly 4X tougher than O1 and about 2X tougher than L6 in the charpy C-notch test.

L6 68 ft-lbs
O1 32 ft-lbs
S7 125 ft-lbs

Folks, I've used it extensively in industry and it is often my first choice over any other tool steel. I've had metal forming dies crash and at 57-58 hard, S7 still shows ductility. It is great stuff!

So, ....as a newbie to custom knife circles....why don't I hear more about S7?

Sincerely,
Rob
 
I have heard of people making swords out of it, though I can't place the names. S5 is even tougher at a higher hardness (58-60 RC). One of the problems with the shock steels is the low wear and corrosion resistance, not critical obviously in a sword. They also don't have the same strength as the high alloy steels at the same RC, so you would see edge roll quicker at the same hardness. Then again if you have to run the other steel softer to get the necessary toughness, the opposite might be true. There could be problems with getting the right stock size for knives as well.

-Cliff
 
well rob i don't think i have ever heard it mention. most of the best ideas come from some one that is new to a industry, that came from a differnt industry, i am all ears to hear more about this steel. would it be suitable for forging or stock removal?
 
Hrisoulas mentions S7 in his books, and speaks well of it in larger blades. He's made a lot of swords, so he may be who you're thinking of, Cliff.
I don't use it because I can't get it. If I could, I'd probably make some hammers and hardies with it first. Then I'd make axes... Do you have a source, Rob?
 
Rob, I have used it & liked it
It`s just hard for me to come by.
Do you know of a good place to get it.
 
ok guys can it be used for stock removal or is it more suited just for forgeing?
 
S5 is a water/oil-hardening steel while S7 is air-hardening.

Swordsmiths like to stick to 5160, it's cheap and easy to work therefore permiting all sorts of experimentation. S5 is expensive and rarely used in that market, but other than possibly being a little tougher, it offers no other benefit. Keep in mind in a sword sized blade, material costs add up. And I never heard users complain that 5160 is not tough enough.

Another problem is that S5 is rumored to be red-short and harder to move under the hammer. Not something smiths like.

I collect swords, and in this market, what we look for is who's doing the heat-treat, how the tang is formed and the blade is tapered, what's the weight and balance, etc. Modern custom swords are already tougher than historical examples, but their weight and balance is wanting compared to the antiques. Steel type is not up there in our concerns. It just doesn't excite sword guys as it does knife guys.

People have different ideas on how a knife should be used, some want to use it like a crowbar. There is only one right way to use a sword, as a weapon. If you break one using it as an axe, it's your own darn fault. :p
 
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