YXR7 vs Laminated ZDP-189

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Sami P

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Aug 7, 2011
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If you are choosing between two knives. One has a blade of tool steel YXR7 @ 64RC, and another one that has a blade made of ZDP-189 @ 67RC sandwiched between ATS-34 @ 62RC. Which one would you choose and why? Will the lamination of the ZDP on the second knife make it as tough as the steel YXR7?
 
Tony8179 said:
I assume that you're asking about Rockstead knives. Go with the YXR7.
Click to expand...

Exactly. Why would you recommend the YXR7?

This is the biggest investment I'm ever going to make in a knife and I want to make sure I do it right.
 
Sami P
Lamination in a knife shorter then say 6" is useless.
For one: Lamination was done to mix in soft spine/sides with a harder edge. This was done to help give some flex to the blade when cutting targets, namely harder targets. However the issue with flexing, and brittleness comes more in the way of daggers and mostly swords longer then 10" where the leverage, speed, and weight of the sword or large dagger far surpass that of a smaller knife. The stresses on the steel on a longer sword can cause hard steel to go past limitations and snap off, yet the stresses would also cause a softer steel to bend permanently.

In short:
Because of the blade length, and usage lamination is more then anything a feature with no use for smaller knives.

Go for the non laminated YXR7.
 
There will be a very significant difference in edge holding, especially for the thin edges between 64HRC YXR7 and 67HRC ZDP-189. Purely form performance standpoint, for a light use knife I'd go with ZDP-189, laminated or not... Hitachi states YXR7 is sort of equivalent of the AISI M2, but has less Mo, W and V (M2 vs YXR7 steel composition comparison) , I don't think that positively affects its performance either.
One other thing non laminated blades have, they can be made thinner, but that depends on the maker. So, if the blade thickness is an issue, you'd have to check that with them.
I simply can not see a reason to use YXR7 in a folder vs. ZDp-189, may be if the price is an issue.
 
YXR7 is a single melt matrix high speed steel. It is a more economical steel making alternative to PM that produces good toughness but not the same levels of wear resistance as many of the PM steels, since they control carbide size and volume through other production means. I would take MHS over a typical ingot steel, but compared to PM the parameters change. ZDP-189 has three times the carbon of YXR7, for example. The toughness at the cutting edge will be quite different and the laminate will be more corrosion resistant.
 
Luis G. said:
Sami P
Lamination in a knife shorter then say 6" is useless.
For one: Lamination was done to mix in soft spine/sides with a harder edge. This was done to help give some flex to the blade when cutting targets, namely harder targets. However the issue with flexing, and brittleness comes more in the way of daggers and mostly swords longer then 10" where the leverage, speed, and weight of the sword or large dagger far surpass that of a smaller knife. The stresses on the steel on a longer sword can cause hard steel to go past limitations and snap off, yet the stresses would also cause a softer steel to bend permanently.

In short:
Because of the blade length, and usage lamination is more then anything a feature with no use for smaller knives.

Go for the non laminated YXR7.
Click to expand...

I do not think the point of laminating the smaller blades is for the flex or such as you mention cutting hard targets..It is to help keep the majority of the blade from easily corroding. The ZDP and YXR7 corrode more easily than say vg10 so they do a thin coating of it over the zdp and yxr7 to help with corrosion. Right?
 
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