HAP40 or REX45?

[Wartstein]

Please not, as far as I am concerned! The lamination and the looks of it are one of the best things on HAP40/SUS410 for me personally, and the huge majority of Spydercos comes in unlaminated steel anyway, so there is a lot to choose from already...

Again, for me it´s not only the unique looks and function, but also the history and tradition behind laminated steel that makes it special imho

I hear you! :)

It's definitely a neat process and full of history. And I also like the looks of the lines. However, I'd prefer to have the best heat treat possible for that steel. Maybe, instead of getting rid of lamination altogether, they'll find a better outer steel to use, able to be heat treated to the max with the core steel (for your benefit ).

I hear you too!

I can totally comprehend the wish to give HAP 40 a "heat treat to the max" like it´s probably more so done with REX 45!
For me though, HAP 40 holds an edge easily long enough, is still quite easy to sharpen and really tough in normal use.
So I personally would have no need for it to be even harder, but sure, if it would be still fairly easy to sharpen, still decently tough but would hold an edge even longer that would not hurt either.

I think much of the appeal HAP40 has to me (beside its great practical properties) is indeed grounded in the laminated form it comes. I just really like that I could tell apart the blade of my own HAP 40 Endura from probably any other within less than a second, due to the unique lamination line each piece has and the also unique and personal "scratch pattern" on the SUS 410. That´s really something special.

If I could keep only ONE folder, it´s very likely I´d choose my HAP40 Endura (or HAP40 Stretch? ) !

[speedseeker]

I voted Rex 45 because its Amareican made. That said, unfair question! Hap 40 is a spectacular steel...love me some Hap 40.

[Larrin]

The properties are identical. It’s the same steel.

[Cycletroll]

With the current heat treat available Rex45 is a far better performer. I have an Endura in Hap40 and as well as a Rex45 Mille and they feel like two different steels. That being said the Hap40 is still a decent performer and gets carried more for edc just because of the form factor.
I imagine that the upcoming k390 Endura will kick both knives to the curb assuming it has similar heat treat to my Police 4

[Catamount123]

I voted REX45, because one of my very favorite Spyders (Native Chief) is coming out in it. I have the Stretch 1, Caly 3 and Wharncliffe D4 in HAP40, though, and am very happy with them.

[JMM]

The properties are identical. It’s the same steel.

Perhaps I'm missing something, but I was very much under the impression that while Rex45 & Hap40 were quite similar, their actual make-up was slightly different, and I thought the heat-treat typically done to them was rather different. I will say I am a huge Rex45 fan and I have had a Hap40 Stretch and Delica and have not found them to perform anywhere nearly as well as the PM2 and Para3 in Rex45 that I have... like not even close. Am I wrong? Larrin, I know you know about 4 or 5.... billion times more than I do about this stuff...

http://www.zknives.com/knives/steels/st ... hrn=1&gm=0

[Larrin]

The properties are identical. It’s the same steel.

Perhaps I'm missing something, but I was very much under the impression that while Rex45 & Hap40 were quite similar, their actual make-up was slightly different, and I thought the heat-treat typically done to them was rather different. I will say I am a huge Rex45 fan and I have had a Hap40 Stretch and Delica and have not found them to perform anywhere nearly as well as the PM2 and Para3 in Rex45 that I have... like not even close. Am I wrong? Larrin, I know you know about 4 or 5.... billion times more than I do about this stuff...

http://www.zknives.com/knives/steels/st ... hrn=1&gm=0

Everything in your chart shows them being the same. There is no “typical” heat treatment that would be different between the two. That would be a manufacturer decision.

[Doeswhateveraspidercan]

Hi Larrin thanks for the confirmation.

I am a little hazy on the details of lamination and heat treatment is their a difference in how a manufacturer would heat treat a monolithic steel versus a laminated?

The few pieces I own are HAP40 in the core and SUS410 on the outside as far as I know this is done to produce the best of all worlds and dates back to the time of the Samurai.

Pretty sure they did not use a stainless steel , but the idea was a hard super sharp core and a softer flexible out casing sandwiched to give the best qualities to a blade.

How could lamination not be superior to just a monolithic slab of HAP40 or REX45?

[Sharp Guy]

The properties are identical. It’s the same steel.

Perhaps I'm missing something, but I was very much under the impression that while Rex45 & Hap40 were quite similar, their actual make-up was slightly different, and I thought the heat-treat typically done to them was rather different. I will say I am a huge Rex45 fan and I have had a Hap40 Stretch and Delica and have not found them to perform anywhere nearly as well as the PM2 and Para3 in Rex45 that I have... like not even close. Am I wrong? Larrin, I know you know about 4 or 5.... billion times more than I do about this stuff...

http://www.zknives.com/knives/steels/st ... hrn=1&gm=0

Everything in your chart shows them being the same. There is no “typical” heat treatment that would be different between the two. That would be a manufacturer decision.

I think the missing piece is the fact that Spyderco does their HAP40 as a laminate which puts limitations on how they can heat treat it. I'm sure I'm not telling Larrin anything but hopefully adds some clarity for JMM

[Skidoosh]

Its a new one for me that they are the same steels. I'm carrying the Caly 3 in Hap 40 and its been a ok steel but it doesn't "pop" for me like super blue or k390. Has anyone been able to do a HRC test on the caly 3?

[Albatross]

From what Sal has said, Seki made the decision on the heat treat.

[dan31]

When laminated steel is heat treated they need to account for both steels. The outer SS requires a different heat treatment to a plain slab of HAP40.

[Larrin]

When laminated steel is heat treated they need to account for both steels. The outer SS requires a different heat treatment to a plain slab of HAP40.

Many laminated steels are heat treated sub-optimally. The stainless hardening temperatures are too high for the low alloy steels (like stainless over Blue steel) and too low for high speed steels. They usually heat treat it for the core steel and ignore the stainless.

[GarageBoy]

What happens to the outer layer when the temperature is too high?

[Albatross]

When laminated steel is heat treated they need to account for both steels. The outer SS requires a different heat treatment to a plain slab of HAP40.

Many laminated steels are heat treated sub-optimally. The stainless hardening temperatures are too high for the low alloy steels (like stainless over Blue steel) and too low for high speed steels. They usually heat treat it for the core steel and ignore the stainless.

From what I understand, some steels pair well with certain stainless steels, and can be heat treated for optimal performance. Are there some steels that don't pair well with stainless steels, making it difficult to heat treat? Not that I'm saying this is the issue with Spyderco's Hap40. This topic just has me curious.

[stockliman]

In a pocket knife, Rex-45 is better. In a properly heat treated chef's knife, HAP40 every day. Horses for courses.

[Sharp Guy]

In a pocket knife, Rex-45 is better. In a properly heat treated chef's knife, HAP40 every day. Horses for courses.

I'm curious, in your opinion, what makes one better in those circumstances then the other?

[Sharp Guy]

I touched up my REX45 Para 3 today after installing new scales. It still had the factory edge and it felt reasonably sharp. After a few swipes on each side with the Sharpmaker fine stones it had that sticky sharp feeling that I like. Just an observation but I don't think it's going to be any harder to get a keen edge on it than HAP40

[Larrin]

What happens to the outer layer when the temperature is too high?

Grain growth leading to toughness reduction.

[Larrin]

From what I understand, some steels pair well with certain stainless steels, and can be heat treated for optimal performance. Are there some steels that don't pair well with stainless steels, making it difficult to heat treat? Not that I'm saying this is the issue with Spyderco's Hap40. This topic just has me curious.

It depends on the stainless steel, of course. The commonly chosen 410 has a hardening range of about 1700-1850F though I did find one datasheet that pushed that up to 1950. Assuming 1700-1850F is more optimal that would mean steels like A2 and D2 would be better choices than steels like Blue Super (1435-1525F) or Hap40 (2100-2200F).