XHP Steel – History and Properties

Great article! XHP was kind of a grey area for me, but this really cleared things up. I sold most of my XHP for S35VN and have been very happy with the switch.
 
good article, Sir. thank you. xhp is a steel I like a lot. good to read about it in detail.....
 
This is of great interest to me. The Domino XHP took a wonderfully fine edge, but it also rings as it cuts hair. It's odd. I think I like the steel better than S35VN.
 
Thanks for more cool data.

Is M2 really that much tougher than M4? And how do you read toughness over an Rc range of 60-64? It also surprises me that O1 is that tough and that A11 is tougher than M4.



XHP-toughness-table.jpg
 
This is the only steel that I have ever based a buying decision on, unless you count “not D2” as a steel.

XXXHP.
 
Fantastic timing! I was looking at a Para 2 in this steel today a friend had.
We actually talked about how much was not really known about it...
and the relative rareness of encountering it.
Very cool, especially the carbide volume and shape as well as the Chromium
in solution. I really prize stainlessness and this info was particularly helpful.
Thank you!
 
I have a Spyderco Dice. Love the knife but I'm not a huge fan of the steel. It loses its razor edge after a dozen cardboard cuts. The working edge lasts for a good bit longer but seems to drop off way faster than D2, at least for me.
 
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Twindog said:
Thanks for more cool data.

Is M2 really that much tougher than M4? And how do you read toughness over an Rc range of 60-64? It also surprises me that O1 is that tough and that A11 is tougher than M4.



XHP-toughness-table.jpg
Click to expand...
As it says in the chart, that is conventional M4 (non-PM). PM-M4 is much tougher. I wouldn’t call that a high value for O1; none of the steels below it are really the gold standard for toughness. For its amount of carbide volume the toughness of O1 is very low. Same with 1095.
 
Great article Dr. Larrin. While XHP may not be as stainless as some others steels like S1 10 V, in my experience it’s been pretty good. It is certainly better than D2, which is a steel that I have enjoyed in my skinning knives. It certainly has better as retention that either D2 or 440 C.
 
Larrin said:
As it says in the chart, that is conventional M4 (non-PM). PM-M4 is much tougher. I wouldn’t call that a high value for O1; none of the steels below it are really the gold standard for toughness. For its amount of carbide volume the toughness of O1 is very low. Same with 1095.
Click to expand...

I did notice the comparison was to ingot M4, but it still surprised me. Thanks for the clarification.

I found this chart on HudsonToolSteel that agrees with you. The advantage of powder M4 over ingot M4 is virtually all in the toughness increase of powder steel processing of M4. Wear resistance is about the same. Even at a point higher Rc, M2 is considerably tougher than ingot M4. Powder M4 is pretty good stuff.

blockM4.jpg
 
Twindog said:
I did notice the comparison was to ingot M4, but it still surprised me. Thanks for the clarification.

I found this chart on HudsonToolSteel that agrees with you. The advantage of powder M4 over ingot M4 is virtually all in the toughness increase of powder steel processing of M4. Wear resistance is about the same. Even at a point higher Rc, M2 is considerably tougher than ingot M4. Powder M4 is pretty good stuff.
Click to expand...
I agree. The good toughness of PM M4 was a relatively early discovery by Crucible metallurgists when they began producing PM steels.
 
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