What is REX 121 steel?

[Doc Dan]

What is REX 121 steel and will we ever see it in a Spyderco? I read somewhere that it can go to very high hardness.

[VashHash]

Mule team is in the works just not sure when. It's got a lot of vanadium, cobalt, and tungsten oh and some carbon. Should be fun.

[Doc Dan]

Great! I want to know more.

[VashHash]

Compared to 440c. Of course some will say this isn't really saying much about the steel but i think it speaks volumes.

[Cliff Stamp]

It is a transition HSS, meaning it is meant to bridge the gap between HSS and cemented carbide :

- https://www.zapp.com/fileadmin/download ... x121_E.pdf" onclick="window.open(this.href);return false;

It is a very high carbide, very high hardness steel, easily reaches ~70+ HRC.

Not many people use it because it is very hard to grind due to the high carbide volume, Farid Mehr does even in large chopping blades. I have one of his in a small blade. Maxamet is a similar alloy, Spyderco is using it in a upcoming Mule.

[dubya3]

You better grab a MULE, or two, when it comes out because it'll be a hot seller. This steel is supposed to be THE steel.

[SpyderEdgeForever]

Nice! That is almost approaching ceramics but in steel.

Any idea on its corrosion-rust resistance, or its wait and see for that?

[Cliff Stamp]

Any idea on its corrosion-rust resistance, or its wait and see for that?

This is a hard question to answer because of the lack of easy quantification. It doesn't naturally form a patina. I have never oiled mine and it shows no sign of discoloring. It is above 52100 in that respect and would be similar to M4 and other mid-chromium steels like INFI. What does tend to happen with those steels is that they often break right to deep pitting. You tend to see nothing, nothing, nothing and then blam - pits. I have done soaks on INFI for example and that is what happens. You end up with little pock marks in the blade if you do leave it wet/salty. They are not stainless, but for mild exposure they do ok. If you are a salt water guy, then you likely would not be happy. I have loaned a few M4 and similar blades to salt water fisherman (professionals) and the blades get pretty chewed up pretty fast. But for kitchen work, they easily handle food acids and don't need the constant 2-cloth method common for Japanese on White/Blue steels.

[HarleyXJGuy]

Pretty sure it is made with the claws of a T-Rex infused into the blade.

Think it was Sal that said so.

[ZMW]

Bringing up an old thread. Is this a possible mule in the near future?

[Skidoosh]

What Chuck Norris shaves with

[ZrowsN1s]

I thought Maxamet was "the steel".

[The Mastiff]

It's a mean looking steel for sure.

[Bodog]

It's ok. High hardness is really the only thing going for it, IMO. If not pushed to over 70 RC with a really strong matrix then other steels would probably be better suited for knife blades.

I sent one to Luong La and he tested the Rex 121 with industry suggested heat treatment and he wasn't impressed, either. At least not compared to 10V at 68 RC or 15V at 70+ with whatever specific heat treatment he uses.

I'm sure some people will get ahold of it and say they like it. I was neutral about the performance but it's not worth the extra cost, IMO. At least not when there are steels that can perform better for less.

I wish spyderco or other big knife companies would start experimenting with heat treatments instead of chasing the latest and greatest steels.

For instance, I sent to Luong a 15V blade measured at 64 RC heat treated using common industry protocols and Luong tested it. Not really impressive. He re-heat treated it using his uncommon method and it measured over 70 RC and performed better in every way. He sent pictures but I can't find the email.

By the way, 15V is packed with huge amounts of vanadium. Whether that's the best overall steel in real world use is debatable.

Maybe Luong can weigh in with his thoughts since he was able to take pictures of the edges before and after testing of Rex 121 and 15V with industry suggested heat treatments and 15V after being reworked.

[Evil D]

I thought Maxamet was "the steel".

Maybe it just has the coolest name, but REX has a lot going for it :rolleyes:

[VashHash]

I wonder if it's still being worked on or if they decided to leave it alone for the time being.

[Evil D]

It's definitely been a couple years since Sal mentioned the mule being in the works. Every mule that's announced I get my hopes up.

[jdw]

Compared to 440c. Of course some will say this isn't really saying much about the steel but i think it speaks volumes.

I see these charts on the board but I have not found them online. Would someone mind posting a link to the site please? Thanks!

[VashHash]

Compared to 440c. Of course some will say this isn't really saying much about the steel but i think it speaks volumes.

I see these charts on the board but I have not found them online. Would someone mind posting a link to the site please? Thanks!

ZKNIVES.COM or there is an app from them.

[Bodog]

I thought Maxamet was "the steel".

Maybe it just has the coolest name, but REX has a lot going for it :rolleyes:

M4 is technically Rex M4