Anticipation of: CPM REX T15 in MT34

[Bolster]

Is your "Mule Sense" tingling for the T15 mule? Have any of you experienced T15 in another blade? What do we know about T15...the good, bad & ugly? Spyderco says it's an end mill steel, so that means I need one. Maybe I can chuck it in my mill and use it to drill tapered holes! (Not.)

[Ramonade]

No experience whatsoever but this is the one I anticipated the most between Rex76, M398 and T15.

Especially since I have to do the best handle yet on one of these blade for someone !

[legOFwhat?]

If this is correct we should be in for another treat!


Sorry for giant pic...

[Josh Crutchley]

I had the pleasure of testing a blade in T15 from Bluntcut Metalworks. I was really impressed with how easy it sharpened, kinda reminded me of Maxamet. It had a custom heat treatment but I would need to try some other T15 to understand the differences.

[Bolster]

Leg's post implies 68-70 Rc. That's pretty durned high. Are we expecting this sort of hardness from the T15 mule?

And...what steel database are you referencing on your phone, Leg? That's pretty cool.

[Josh Crutchley]

Leg's post implies 68-70 Rc. That's pretty durned high. Are we expecting this sort of hardness from the T15 mule?

And...what steel database are you referencing on your phone, Leg? That's pretty cool.

That's the range for Zmax. I think he was referring to where it said Zmax was comparable to T15. I would expect something around 65-67 hrc.

[Larrin]

Maxamet is a higher carbon, higher cobalt, slightly higher vanadium version of T15. CPM-T15 is normally tops out at 66, maybe 67 Rc. I would anticipate something like 64-66 Rc depending on how they want to heat treat it.

[legOFwhat?]

Leg's post implies 68-70 Rc. That's pretty durned high. Are we expecting this sort of hardness from the T15 mule?

And...what steel database are you referencing on your phone, Leg? That's pretty cool.

The app is z-knives. I have no idea how accurate it is.

[Manixguy@1994]

This steel is so interesting and after reading up on it , just may have to order one . Dan

[Bolster]

This steel is so interesting and after reading up on it , just may have to order one . Dan

Don't keep it to yourself, ManixMan--share the knowledge! What did you discover?

The app is z-knives. I have no idea how accurate it is.

Must be Android only. Couldn't find for iPhone. All I can find is a game that features a knife-wielding bunny. And absolutely no info on the steel that's used in the bunny's knife.

WAIT. Here it is, in Apple App Store called "Knife Steel Composition Chart." Thanks, Leg.

[Manixguy@1994]

This steel is so interesting and after reading up on it , just may have to order one . Dan

Don't keep it to yourself, ManixMan--share the knowledge! What did you discover?

The app is z-knives. I have no idea how accurate it is.

Must be Android only. Couldn't find for iPhone. All I can find is a game that features a knife-wielding bunny. And absolutely no info on the steel that's used in the bunny's knife.

WAIT. Here it is, in Apple App Store called "Knife Steel Composition Chart." Thanks, Leg.

I’ve have been behind reading up about this steel . I recently read Dr. Larrin’s article on his site and was impressed. I also think it is time for me to give a tool steel Mule a try . Nothing really earth shattering just good information and history of the steel . Dan

[Bolster]

Re-upping one of Dr. Larrin's graphics that gives some context for T15. IIRC, Larrin drew the curves in the neighborhood of the best examples of tool steel, rather than through all the examples.* In other words, I don't think the curve represents a quadratic regression curve attempting to fit all the tool steel points. If true, then I suspect that T15 is not necessarily a laggard that's "behind the curve," I'm guessing (trying to fit a regression curve by eye, yes, dangerous) that T15 is probably about where you'd expect it to be for toughness, given its CATRA scores. Bested by Vanadis 8, but outshining Rex 76, in this graphic.

*A little confusing since the stainless steel curve appears to be more in the swarm of points. But I'm still guessing these are not regression-fit curves, since Dr. Thomas didn't include the formula for the line. If they were regression curves they'd probably have a formula attached.

[Josh Crutchley]

Re-upping one of Dr. Larrin's graphics that gives some context for T15. IIRC, Larrin drew the curves in the neighborhood of the best examples of tool steel, rather than through all the examples.* In other words, I don't think the curve represents a quadratic regression curve attempting to fit all the tool steel points. If true, then I suspect that T15 is not necessarily a laggard that's "behind the curve," I'm guessing (trying to fit a regression curve by eye, yes, dangerous) that T15 is probably about where you'd expect it to be for toughness, given its CATRA scores. Bested by Vanadis 8, but outshining Rex 76, in this graphic.

*A little confusing since the stainless steel curve appears to be more in the swarm of points. But I'm still guessing these are not regression-fit curves, since Dr. Thomas didn't include the formula for the line. If they were regression curves they'd probably have a formula attached.

I think people get caught up on charpy toughness a little too much. It doesn't really correlate to edge stability in my experience. It does a good job showing what happens at the limit but not below. There's two failure modes for steel ductile and brittle. If the steel is ductile it will deform before it fractures giving higher toughness numbers. A brittle steel will just hold form until failure resulting in lower numbers. I think what happens before the limit might be more important than where that limit is.

[legOFwhat?]

Where you at T15?

[Tucson Tom]

Interesting that Rex45 and Rex76 are close neighbors on that chart. Two of my absolute favorite steels.
I used to cry every night that there was no Rex-45 mule, but the Rex-76 mule took all the tears away.

[Fireman]

Re-upping one of Dr. Larrin's graphics that gives some context for T15. IIRC, Larrin drew the curves in the neighborhood of the best examples of tool steel, rather than through all the examples.* In other words, I don't think the curve represents a quadratic regression curve attempting to fit all the tool steel points. If true, then I suspect that T15 is not necessarily a laggard that's "behind the curve," I'm guessing (trying to fit a regression curve by eye, yes, dangerous) that T15 is probably about where you'd expect it to be for toughness, given its CATRA scores. Bested by Vanadis 8, but outshining Rex 76, in this graphic.

*A little confusing since the stainless steel curve appears to be more in the swarm of points. But I'm still guessing these are not regression-fit curves, since Dr. Thomas didn't include the formula for the line. If they were regression curves they'd probably have a formula attached.

I think people get caught up on charpy toughness a little too much. It doesn't really correlate to edge stability in my experience. It does a good job showing what happens at the limit but not below. There's two failure modes for steel ductile and brittle. If the steel is ductile it will deform before it fractures giving higher toughness numbers. A brittle steel will just hold form until failure resulting in lower numbers. I think what happens before the limit might be more important than where that limit is.

Cutting a nail and a lateral deformation test is better for a knife steel test.

[Fireman]

Interesting that Rex45 and Rex76 are close neighbors on that chart. Two of my absolute favorite steels.
I used to cry every night that there was no Rex-45 mule, but the Rex-76 mule took all the tears away.

Intervention time. Are the carbides in the room with you now?

[Fireman]

Maybe you have to show proof of diamond sharpener before you buy a mule in these type of steels :)

[standy99]

Got to be dropping soon…….

[JRinFL]

Re-upping one of Dr. Larrin's graphics that gives some context for T15. IIRC, Larrin drew the curves in the neighborhood of the best examples of tool steel, rather than through all the examples.* In other words, I don't think the curve represents a quadratic regression curve attempting to fit all the tool steel points. If true, then I suspect that T15 is not necessarily a laggard that's "behind the curve," I'm guessing (trying to fit a regression curve by eye, yes, dangerous) that T15 is probably about where you'd expect it to be for toughness, given its CATRA scores. Bested by Vanadis 8, but outshining Rex 76, in this graphic.

*A little confusing since the stainless steel curve appears to be more in the swarm of points. But I'm still guessing these are not regression-fit curves, since Dr. Thomas didn't include the formula for the line. If they were regression curves they'd probably have a formula attached.

I cannot speak to your other points, but I do find it curious that many peoples favorite steels fall right in between the two curves.

toughness-edge-retention-5-9-2021 copy 4.jpg (28.85 KiB) Viewed 820 times