Spyderco HAP40 Thread

Billy516 said:
Been carrying my HAP40 Delica since I got it a couple of weeks ago. Kicked some much "nicer" and pricier knives out of my pocket. Nice to rediscover this awesome model in such an amazing steel. FYI, been just touching it up on the SM at the 30 deg setting and stropping. It is ridiculously sharp!
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I love this image! :thumbup:
 
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So, it is my understanding that HAP40, a tool steel, has just under 5% Cr. My metallurgy is a little rusty (if you'll excuse the pun); I know that chromium increases rust resistance, but what other qualities might that Cr content impart to the steel?
 
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I'm still learning all this, so keep that in mind.

In this steel, probably all the Cr is going towards that top layer of chrome for corrosion resistance. In all tool steels, there is generally between 4-6% Cr. The other alloying elements are creating the carbides. In a steel like ZDP-189 (20% Cr) some of its Cr is used in carbide creation, or to assist in raising the potential final hardness. HAP40 is interesting because it has Cobalt. Cobalt is used for higher red hot hardness which is pointless for a knife steel. However this steel was not ever intended as a blade steel. I'm curious if that Co has other effects on knife edge properties. I'd like to get some M3 which HAP40 basically is with the addition of Co. Do a little usage comparison.
 
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Got my HAP40 Endura and CTS-XHP PM2 in today. Loving all this orange!

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Kwon Kwang said:
So, it is my understanding that HAP40, a tool steel, has just under 5% Cr. My metallurgy is a little rusty (if you'll excuse the pun); I know that chromium increases rust resistance, but what other qualities might that Cr content impart to the steel?
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Chromium is a carbide former and is the main carbide forming element in ZDP-189. It also increases obtainable hardness and tensile strength but its best known for making steel stainless. Typically, 13% or more chromium will make a steel stainless.
 
nccole said:
I'm still learning all this, so keep that in mind.

In this steel, probably all the Cr is going towards that top layer of chrome for corrosion resistance. In all tool steels, there is generally between 4-6% Cr. The other alloying elements are creating the carbides. In a steel like ZDP-189 (20% Cr) some of its Cr is used in carbide creation, or to assist in raising the potential final hardness. HAP40 is interesting because it has Cobalt. Cobalt is used for higher red hot hardness which is pointless for a knife steel. However this steel was not ever intended as a blade steel. I'm curious if that Co has other effects on knife edge properties. I'd like to get some M3 which HAP40 basically is with the addition of Co. Do a little usage comparison.
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I'm sure you know, but to clarify anyone reading, high speed tool steels (HSS) are different from all other tool steels. HSS is designed to cut other steels at high speeds, which builds up heat on the cutting edge. in excess of temperatures that would otherwise soften (anneal) other steels (non HSS). The ones with cobalt can get red hot and retain their hardness, Those without will anneal below red heat (M2, M3)

At this point, I have a question. At what tempering of a steel designates it high speed? ex: 1000 degrees?

M2 is considered a high speed that has no cobalt. M35 is M2 with 5% cobalt. I have several knives in both steels.

M3 has all the major components of Hap40 except cobalt, but also has traces of nickle, manganese, silicon, and copper. M36 is similar to M3 plus the cobalt, according to this reference.
http://zknives.com/knives/steels/steelgraph.php?nm=HAP40, m3, m36&hrn=1&gm=0

To compare M3 to Hap40, you can get a custom builder to make one (highly unlikely), make one yourself, or I could temporarily send you one of mine. The only problem with mine, they are tempered much harder, not apples to apples.

The top one has been in use a few years. The bottom one was completed a few months ago. Just simple no nonsense. Made for use only, critical collectors need not look.

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I should have included a Hap40 delica or endura for reference. Oh well, maybe another time.

I think there should be a thread dedicated to high speed tool steels, being as rare as they are in the knife blade world, to educate those that are unaware.
 
The high speed steels also seem a little lighter. I'm guessing because the cobalt displaces a heavier element or elements in the alloy?
 
TheOutdoorNerd said:
The high speed steels also seem a little lighter. I'm guessing because the cobalt displaces a heavier element or elements in the alloy?
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I don't recall noting their densities, but I'm guessing any real difference in a blade that small would only be detectable by a precise scale. Some have suggested they are ground thinner than the normal VG-10 models.
 
Finished it up, it did fine I think at 320 cuts, it is .024" behind the edge. :)
 
Stretch, Dragonfly, Manbug, and Ladybug preoders are on the front of the local store's page. Based on past performance for Spyderco coming soon they're just days away.
 
Danke42 said:
Stretch, Dragonfly, Manbug, and Ladybug preoders are on the front of the local store's page. Based on past performance for Spyderco coming soon they're just days away.
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I like the sounds of that. I hope you're right danke!!
 
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