ttt diagram for S5

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wnease

wnease

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anyone have a link to a ttt for S5?

just spent an hour with google, no luck
 
What exactly do you need . Without photographing the diagram - Ms is 500 F, Mf near 100 F, 15 seconds to get below 900 F .Let me know if you need other info about S5.
 
thanks mete, the main thing i like to know is the time to get under the pearlite nose, 15 seconds sounds like a lot, air hardening, though the manufacturers say harden in oil
 
If, during the course of your research, you come across a supplier for S5 barstock (or cut sheet) in 1/4" thickness by at least 2" wide, please post the source here. :)

thanks.
 
will do, it's tougher and harder than S7, makes me wonder why anyone would use S7
 
S5 is very close to 9260 which may be more available in sizes suitable for knives.
 
Actually, out of curiosity, I decided to make a few calls looking for S5 stock myself, and thought I'd share.

Latrobe Steel has a warehouse in Tennessee where they stock S5 plate in .337" thickness. (This aught to be about perfect for one of your katana- most of the originals I've seen hovered around 1/3" thick at the machi.) They will cut it into whatever width you need, and the bars would be at least 6' long. I just spoke with Jim at their Ohio office- 1-800-321-6446.
 
I've got this on S5 ( figures given are for blade thicknesses):

Forge hot - 1850-2050F
Normalizing not recommended
Stress relieve ( optional) at 1200-1245F and hold for 30min.
Anneal at 1425-1475F for 1 hour, cool at 25F/hr to 900F, then air cool.
Austenitization - Preheat at 1400F with a slow heat-up.Austenitize at 1600F, hold for 5 minutes
Quench in oil
Temper immediately at 450F for a mid Rc50s. (cracking may be a problem if temper is delayed)

pearlite nose at 15-16 seconds. Once past the nose, there is lots of time, so straighten at 500-800F.
Ms 500f, Mf room temp
Benefits from cryo

If you are brave, and can stand failure, it can be water quenched with austenitization at 1575F.

Don't over soak or overheat in austenitization, as grain growth is a problem with too much time or temperature.

Foil wrapping or blade coating will help decrease decarb.

Stacy
 
Thanks Stacy, but I am again intrigued by the possibility of air quenching this steel to full hardness, given the 15 seconds to get down to 900F.

Toughness at RC 59 is charted at higher than S7 at RC 57, I was aiming for 59+
 
S5 is not an air hardening steel. The Rc59+ you want will be better achieved with another steel. S5 hardens at quench in oil to somewhere around Rc58-59. If water quenched, the possibility of a RC61-62 at quench is attainable, but a temper at 400F would drop that to Rc57-58.
What type of blade are you making? S5 might make a good sword, but it isn't the steel for a slicer.

Stacy
 
bladsmth said:
S5 hardens at quench in oil to somewhere around Rc58-59. If water quenched, the possibility of a RC61-62 at quench is attainable, but a temper at 400F would drop that to Rc57-58.
Click to expand...

According to Latrobe's Spec Sheet, It will reach 61 Rc with an oil quench if Austenized at 1700*. (They recommend between 1600-1700*f for oil quenching.) This is the figure they use on their tempering/toughness chart, which shows it still above 60Rc with a 400* temper.

It does say Critical Temp (Ac1) is 1410*, so are we doing something bad with the grains by autenizing it higher? Even if we are, I still find it interesting that it still shows such a high toughness at these higher hardnesses.

I welcome advice from those experienced with this material though, of course. Does their spec sheet data not translate as well to blades?
 
that's kind of what i was wondering myself... blade thickness is smaller than test blocks usually so I figured high hardnesses were easily achieved, and I also read high as-quenched hardness, with 300F temper giving RC 60, RC 59-60 giving vastly more toughness than S7 at RC 57...

but i was concerned about the higher temperature prior to quench.

Imagine a sword blade tougher than any other but hard enough to support a thin edge too...
 
I think you are trying to create something that is contrary to the reality of a sword.
The Japanese swords have hard edges and soft bodies, but trying for a hard thin edge and a tough sword ( "tougher than any other" ?) will most likely fail on one count or the other. High hardness is not usually a requirement ( or even a desirable feature) on a sword blade over one shaku ( 12").

However, making a sword from S5 will be a good exercise in HT ability.
I suggest you make one, hardening it in oil ( it won't work if air quenched),

Before you make the actual sword, make a test piece from the same piece of steel. Make a section of sword blade about 12" long,doing the HT exactly as you intend to do on the final blade. Test the Rc on a tester . Test 1/4" from the edge and at the center of the blade post quench, and after tempers at 400F and 450F. post the results here.

I have some S5 ( or is it S7) round bars in the smithy I have been intending to forge into a long sword. Your results will be of interest.

Stacy
 
I work at a steel mill and we roll S-5, S-7, 440-C, 154-CM all the time. Let me know what you are looking for.
 
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thanks barneybud

Stacy,

according to the charpy tests the toughness of S5 at RC 59 is far beyond the pearlite junk in the body of a japanese sword(though the failure mechanism might be different), and it will be several times stiffer... the edge will withstand rapid loading better than untempered martensite... it sounds perfect, on paper. i think you are right that it will be tricky to heat treat, keeping it straight and getting it to full hardness etc, which is why i'm still pondering S7 with its nice, slow quench
 
Imagine a sword blade tougher than any other but hard enough to support a thin edge too...
Click to expand...

Considering that edge strength and stiffness go up so rapidly with small increases in thickness, I don't think we can really get edges much any thinner than historical blades (or at least enough to really make a worthwhile difference). But by using a tough modern steel we may be able to get greater durability without having to beef up the edge unnecessarily, which is perhaps what you meant anyway...

However, making a sword from S5 will be a good exercise in HT ability.
Click to expand...
i think you are right that it will be tricky to heat treat, keeping it straight and getting it to full hardness etc,
Click to expand...

FWIW, on their Shock Steels Bulletin, Latrobe considers S7 more dimensionally stable than S5, but S5 is more stable in heat treat than L6, too. So I wouldn't think warpage should be any bigger of a concern than usual for any sword. ? Are you doing this in salt pots, where you can quench it below the pearlite nose & can keep it straight by hand as it transforms?

High hardness is not usually a requirement ( or even a desirable feature) on a sword blade over one shaku ( 12").
Click to expand...

Well, why not? What's wrong with an edge that's hard & strong enough to resist denting, tearing, and rolling, if it's also tough enough to not chip out at that higher hardness? I mean, I don't want to come across wrong here- I don't have the answers myself. But, at least on Latrobe's papers, S5 is tougher at 61 Rc than L6 is at 53 Rc. Wouldn't that just be cool as all get out, if real world testing confirmed it?

I'm more familiar with European swordsmanship, where blade on blade contact is normal. I can't think of any instances where a sword that was a little more durable would be a problem. ?? Maybe they wouldn't behave in quite the same way as our ancestors would have expected though. For instance, here's one move from the Italian tradion where you bind the opponent's sword down & step on the blade to control it, allowing you to do as you wish:

121leu.jpg


One translation of the caption is, "Your sword is either bent or broken and with mine I can wound you up or down"

:)
 
bladsmth said:
Before you make the actual sword, make a test piece from the same piece of steel. Make a section of sword blade about 12" long,doing the HT exactly as you intend to do on the final blade. Test the Rc on a tester . Test 1/4" from the edge and at the center of the blade post quench, and after tempers at 400F and 450F. post the results here.
Click to expand...

Here's something I was thinking of for testing, and I'd like to get some input from you folks.

I get a bar of steel long enough that I can cut off, say, three different pieces for testing different heat treats/hardnesses. They would be wide enough so the edge could be ground with similar geometry as the blade I want, with a flat above the grind, kinda like a high saber grind. Maybe 2 or 3 inches long. The flat spot would give a nice area for Rockwell readings, and there would be a couple holes drilled through near the spine so I could bolt it to a piece of pipe with some flanges welded to it.

The idea being, I could put a wooden handle in the pipe and basically have a tomahawk with interchangeable bits. This way I'd have several smaller pieces of steel with different heat treats that could be made fairly easily, and by putting them on a long handle, I could give them a chopping workout to replicate the dynamic impacts and stresses a long blade might see. Or even mount them in some other rig for more controlled testing. Thoughts?
 
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