5160 or L6 for swords

mross said:
I would go with 5160 just because there are more real world user swords out there made with 5160 than L6.
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That's probably because L6 wasn't available "back in the day" or even as readily available in the recent past as it is today. . .I personally think that L6 would be an excellent choice for a "battle ready" sword based on it's uses in industry today (sheet metal shears, etc.); we use it to make "roll-off" wheels for pipe cutting applications and seal weld cutters for valve refurbishment at work. I can't remember what we were using, but it took considerable effort, time, and the "roll-off" wheels would chip quite frequently. . .once we started using L6 those problems went away.

That being said it would seem to me that L6 would be incredibly suited to a blade that would be pitted against another blade and armor. . .
 
atomicjoe23 said:
That's probably because L6 wasn't available "back in the day" or even as readily available in the recent past as it is today. . .I personally think that L6 would be an excellent choice for a "battle ready" sword based on it's uses in industry today (sheet metal shears, etc.); we use it to make "roll-off" wheels for pipe cutting applications and seal weld cutters for valve refurbishment at work. I can't remember what we were using, but it took considerable effort, time, and the "roll-off" wheels would chip quite frequently. . .once we started using L6 those problems went away.

That being said it would seem to me that L6 would be incredibly suited to a blade that would be pitted against another blade and armor. . .
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Can't argue with that. Howard Clark makes an awesome L6 Bainite blade. 5160 is a much eaiser heat treat to bring out the full potential. If I new the blade was made by Howard, that would be my choice, because I would know the heat treat was done right. If I did not know the smith than I would go with 5160, because it's much eaiser to get right.
 
Either is good stuff. Doesn't matter much to me so long as the sword is well-made and the HT is good.
 
i suggest go with either s7 or s5, i personally perfer s7. s5 score a little higher impact toughness when its unnotched. but s7 preformed way better when its V or U notched. as a sword, i don't see much of a big difference between s5's 59hrc to s7s 57hrc.
 
hammerfall you are the only person besides myself I think to quote that information... thanks I thought I was going crazy. I went with S-7 for about 25 recent blades because they might get notched during abuse and notched toughness is important when I smash a couple feet or more of shaving sharp steel into various objects.

S-7 is also tougher by far than L-6, notched or unnotched, at my hardness (RC58)
 
I made some utility knives from L6 and set them off out there with a coating of K&G Gun Kote in basic flat black and a sort of medium brown. All of them (30 or so) have held up very well and no complaints even with everyday use. (shrug). I have also used 1095 for swords and they are fine. Just have to have the right heat treat is all. I like a hard edge (almost 60) with a softer back or middle (on double edged swords) and spring steel hardness throughout. That way you have it hard where you need it and it remains flexible enough to handle shock. In the old days there was no 5160, 1095, O1...or what have you. They made swords from what you had and the blacksmith controlled the carbon, heat treat and hammer forged shape. It all goes back to those techniques. I know some one that makes stage steel (hit edge to edge all day long) and they hold up well but are not as pretty as some. Any less of a blade used against it would cause injury because that inferior blade would shatter or bend under the force. Case in point: the swords used in the Rock's movie 'Scorpion King" were of hardened aluminum alloy. The daily forces of shooting blade on blade and heating the sword with burning flames caused it to shatter explosively on impact during a fight (they used it in the film). It all goes back to heat treat, heat treat, heat treat.
 
Hammerfall & wnease-
Thanks for pointing that out. I checked my spec sheets & never even noticed that before; earlier I was mainly looking at Timken's comparagraph which shows unnotched izod.

Charpy V Notch graphs provide the following (approx)
S7 @ 57 Rc = 12.5 ft-lbs
S5 @ 60 Rc = 8.5 ft-lbs

However, to put those numbers into perspective, the chart for L6 maxes out at only 5 ft-lbs once you temper it all the way down to around 52 Rc. And L6 is already very highly regarded as a tough and strong sword steel.

For my part, the only time I actually broke a blade via impact, it didn't crack at any of several severe edge notches. Instead, it broke directly at the point where the impact occurred, since the force simply exceeded what the steel could take (and any of the steels we're discussing here are far far tougher than that one was- high carbide stainless). The 5160 blade I've been using since then has not given me any worries of breaking in half (though this is with a short sword). I'm more interested in improving edge durability in general now through hardness, so S5 is still the one on my radar to try eventually.

I wish I had the time and resources to really find my own answers with this stuff. Some of these shock steels really sound incredible on paper; I wonder how well that would translate to actual use.
 
Possom that's interesting; the last blade I broke was 8670m banite @RC57 and it did not break at the notches from previous testing abuses. It didn't even break at the point of impact. 10 inches (at the point) was stuck in the lumber I struck and the rest stayed together in my hand. Harmonics are a major factor in sword blade failure and I do not pretend to understand them! However, my heat treater understands air hardening shock steels very, very well, and that gives me confidence in my S-7 swords. FWIW my 5160 (RC58) heat treated by the same heat treater suffer substantial ductile failure long before they show any signs of fracture... it's just that they warp a lot more even in positive pressure gas quench and for me it has been difficult to obtain compared to S-7.

Broe I agree heat treat is very important, but so is grain size, carbide size and distribution, percentage of retained austenite, proportion of plate versus lath martensite, strength, fracture toughness, impact toughness...much is controlled by the HT but with the wrong alloy, even the wrong pour of a particular alloy, no heat treat will work. Btw I don't understand much of the terms I just listed ;) but metallurgist-blademakers do!

One other thing, I don't use a sword like a swordsman ( because I am not a swordsman ). I use a sword pretty much like I am trying to break it, and I swing them faster (hitting 100 mph with a 3 lb sword isn't difficult) than most humans can, with perhaps less precision than most. So my point on durability is perhaps moot, and to a swordsman it ain't the tool it's the fool...

so to the original poster, sorry to have contributed to thread drift, but maybe it doesn't matter whether you use L-6 or 5160, or even if the heat treat is optimized... maybe we need to optimize our sword use (not me though, I'll go back to smashing!!!)
 
From the little exposure I've had to these steels, I would have to say, personally despite many people always saying 5160 is the toughest steel, I have observed L6 to be more resilient to impact toughness. Even though 5160 has a little bit less carbon than L6, which would make you think it would be tougher, L6 has quite a bit of nickle in it which greatly increases toughness and ductility. From my observations they are both very tough but exhibit different characteristics. 5160 tends to flex a great deal but when it reaches its point of failure will almost always just snap. Never have i personally seen 5160 take a set. While L6 will also flex quite a bit, but then start to permanently bend before reaching a breaking point. On hard impacts L6 is also more likely to deform before it breaks, while 5160 will have little to no deformation ( talking about thick spine) but then snap clean off when Its reached its limit. The amout of force exerted on the blades are about the same for both to get them to start flexing. I don't have any numbers, but I seen charts indicating L6 having the same toughness as A8 tool steel. And A8 at 59rc has a charpy impact toughness of 165 joules. For reference CPM-3V has a charpy impact value of 104 joules at same Rockwell hardness. So L6 will be around that figure. Hope this helps.
 
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