New Military Sprint!! CPM Rex 45

JackTheKnifeGuy said:
Alright lets start brainstorming about how this steel might preform... because I have no idea how Hap 40 performs in terms of ease of sharpening, wear resistance, toughness, and stain resistance... school me lol :oops:
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HAP40 = CPM Rex 45 = (CPM M4 + 8% cobalt)
http://www.zknives.com/knives/steels/steelgraph.php?nm=hap40,cpm m4,cpm rex 45&hrn=1&gm=0

I say equals because the composition is close enough to be the same within the margin of error you'd get in steel production - I really doubt anyone would be able to tell the difference between HAP40 and CPM Rex 45 without a spectrometer.

Spec sheet: https://www.alphaknifesupply.com/Pictures/Info/Steel/CPMRex45-DS.pdf
Based on that, adding the cobalt lowers both the toughness and hardness by a small amount. In exchange, you get red hardness (the ability to withstand stress at very high temperatures) and likely some corrosion resistance. The cobalt may help with sharpenability only in that it's reducing the overall hardness. Overall, based on the specs, I'd say it's similar to M4 but not quite as good.
 
It's going to depend on how spyderco does the heat treat to see how it performs... if they do it right it should be very similar to good Hap40 and better edge retention and toughness than M4. The reason i say good Hap40 is cause the Hap40 delicas weren't done well... you need to go to a higher hardness on it and Rex 45 to make it work well
 
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tyyreaun said:
HAP40 = CPM Rex 45 = (CPM M4 + 8% cobalt)
http://www.zknives.com/knives/steels/steelgraph.php?nm=hap40,cpm m4,cpm rex 45&hrn=1&gm=0

I say equals because the composition is close enough to be the same within the margin of error you'd get in steel production - I really doubt anyone would be able to tell the difference between HAP40 and CPM Rex 45 without a spectrometer.

Spec sheet: https://www.alphaknifesupply.com/Pictures/Info/Steel/CPMRex45-DS.pdf
Based on that, adding the cobalt lowers both the toughness and hardness by a small amount. In exchange, you get red hardness (the ability to withstand stress at very high temperatures) and likely some corrosion resistance. The cobalt may help with sharpenability only in that it's reducing the overall hardness. Overall, based on the specs, I'd say it's similar to M4 but not quite as good.
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Cobalt increases hardness not decreases it...
 
Search for the Crucible data sheet for Rex 45. It shows Rex 45 has noticeably lower toughness than M4. It also shows M4 at 65 has more wear resistance than Rex 45 at 67. Spyderco runs M4 a little lower than this, and Rex 45 at 66-67 (ave 66.5) so wear resistance in real knives is probably a wash. Rex 45 will have a very good sharpening response, better than M4 if Hap40 is any indication, and M4 is no slouch. Corrosion resistance is something that will be learned with experience - I think this is the first production Rex 45 so there is no practical history.
 
According to Sal the Rex 45 is averaging 66.5 rc hardness..that will definitely make a difference.

Should be interesting..
 
Riz! said:
It seems to me that Spyderco loves to run their steels harder than most other manufacturers. I think its part of what makes them perform so well
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They are masters of the HT.
Sal, is so very knowledgeable.
 
BaconSlayerCM said:
It's going to depend on how spyderco does the heat treat to see how it performs... if they do it right it should be very similar to good Hap40 and better edge retention and toughness than M4. The reason i say good Hap40 is cause the Hap40 delicas weren't done well... you need to go to a higher hardness on it and Rex 45 to make it work well
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What?
 
Danke42 said:
What?
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Guess i worded it wrong... spyderco didnt do as high of a HRC on the hap40 sprint runs as they should have to get the nost out of it. I was saying that if they dont make that same mistake and run the Rex 45 to a higher HRC it should be really good... if they dont it will be beaten by the m4 version of the military easy in almost every way.
 
For an orange, it looks great. Does hardness=brittleness in this case, as it does with s90v, or does the cobalt, lower carbide fraction and less chromium change the equation somehow? Does anyone know the hardness at which s30v is run on the Millie? I’m not used to paying $180 for Millie’s without at least 1 Ti slab, except for the cts-204p version. I wanna see how these perform first, but being a limited run I don’t know if they’ll last.
 
If this is really an American analog of HAP40 then I think we will see comparable performance, which isn't all that impressive compared to M4.

In Cedric Ada's tests, HAP40 did well but not outstanding and not as well as many thought. This is of course one one parameter (wear resistance) but is worthy of note. M4 seems to make excellent use of it's proportionally lower carbide fractions (I believe around 12%?) much like Cruwear/PD1 does. These steel outperform many much higher carbide steels (like S90V).

I don't get the appeal of another HSS when we have already had the same models in M4. Also, orange is hideous.

I'll keep my experimentation to the VToku Endura I just got, a low alloy tungsten steel is something I haven't had before.
 
John_0917 said:
If this is really an American analog of HAP40 then I think we will see comparable performance, which isn't all that impressive compared to M4.

In Cedric Ada's tests, HAP40 did well but not outstanding and not as well as many thought. This is of course one one parameter (wear resistance) but is worthy of note. M4 seems to make excellent use of it's proportionally lower carbide fractions (I believe around 12%?) much like Cruwear/PD1 does. These steel outperform many much higher carbide steels (like S90V).

I don't get the appeal of another HSS when we have already had the same models in M4. Also, orange is hideous.

I'll keep my experimentation to the VToku Endura I just got, a low alloy tungsten steel is something I haven't had before.
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The thing is tho is that spyderco didnt get all they could out of their hap40... it needs to be a higher hrc to get the full benefit from having the cobalt which allows a higher hrc without giving up much toughness and sharpenability
 
John_0917 said:
If this is really an American analog of HAP40 then I think we will see comparable performance, which isn't all that impressive compared to M4.

In Cedric Ada's tests, HAP40 did well but not outstanding and not as well as many thought. This is of course one one parameter (wear resistance) but is worthy of note. M4 seems to make excellent use of it's proportionally lower carbide fractions (I believe around 12%?) much like Cruwear/PD1 does. These steel outperform many much higher carbide steels (like S90V).

I don't get the appeal of another HSS when we have already had the same models in M4. Also, orange is hideous.

I'll keep my experimentation to the VToku Endura I just got, a low alloy tungsten steel is something I haven't had before.
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Off topic, how do you like the Vtoku and do you think it compares favorably with superblue? I’m waiting for a stretch2, but don’t know when or whether yet.
 
Yonose said:
Off topic, how do you like the Vtoku and do you think it compares favorably with superblue? I’m waiting for a stretch2, but don’t know when or whether yet.
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Just got it so I can't say yet, but one initial observation is that the lamination lines are much harder to see in person than in pics. I have only had composite blades before (where there is an upper and lower section).

I'll be EDCing this knife from now on mostly, I recently cut down my collection to focus on a few diverse high quality knives plus two beaters (Endura, Emerson Sheepdog, Pac Salt and Kershaw/Emerson and Tenacious as beaters) so this will get plenty of use. I understand it has very high hardness (65-67) and also very good toughness (which is a rare mix) and is somewhat similar to the properties of tungsten (which is the overwhelming carbide former). 1.1% C with 1.5% W as the only carbide former is a pretty unusual alloy. Much like HAP45 & other HSS/carbon steel I expect it will rust pretty easily. I'm not Tuf Clothing yet but I probably will, especially if I take it to Hawaii in August with me.
 
John_0917 said:
If this is really an American analog of HAP40 then I think we will see comparable performance, which isn't all that impressive compared to M4.

In Cedric Ada's tests, HAP40 did well but not outstanding and not as well as many thought. This is of course one one parameter (wear resistance) but is worthy of note. M4 seems to make excellent use of it's proportionally lower carbide fractions (I believe around 12%?) much like Cruwear/PD1 does. These steel outperform many much higher carbide steels (like S90V).

I don't get the appeal of another HSS when we have already had the same models in M4. Also, orange is hideous.

I'll keep my experimentation to the VToku Endura I just got, a low alloy tungsten steel is something I haven't had before.
Click to expand...
In this case that test means nothing..the Hap 40 series wasn't even close to 66.5 rc..66.5 will change things and could change them a lot..remember the rc hardness scale is not linear and even 1 or 2 points makes a big difference.

We can speculate forever but we wont know until they are in hand and used/tested.
 
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ToxicBot11 said:
In this case that test means nothing..the Hap 40 series wasn't even close to 66.5 rc..66.5 will change things and could change them a lot..remember the rc hardness scale is not linear and even 1 or 2 points makes a big difference.

We can speculate forever but we wont know until they are in hand and used/tested.
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Yea thats what I've thought to... the spyderco hap40 has been lack luster but ive had other hap40 knives that seem to hold an edge forever... which i hope the Rex45 will as well
 
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