Replies to This Discussion

Permalink Reply by kage on September 10, 2010 at 15:07

As with most things, what's best in knife steel will be determined by blade design, intended use and environment.

ZD 189 can either come in as a folded laminate or as straight stock. If as a laminate, the outer fold/sleeve will be a softer steel. This can be prone to scratching on the blade face. ZD 189 is composed mainly of high levels of Carbon and Chromium, so it would be good for moist/salty environments. But it also makes a chore out of re-sharpening and honing. A thin edge (13° - 17° bevel angle) and either a long blade (such as a fillet knife) or a short blade (such as a carver) would be better suited for this steel.

CPM M4 is a high-end tool steel composed with high quantities of Chromium, Molybdenum, Vanadium, and Tungsten, which contributes to its industrial nature/usage. One could regard such a steel as basically a "super carbon" steel, and its applications would be utilized in the same manner as one would use any such high carbon blade (such as in Bushcraft, Camping, or other extreme hard use endeavours) in moderate environments (with a 15° - 20° bevel angle.)

D2 is another tool steel with slightly more Carbon and Chromium than M4 and is often described as a "semi-stainless steel." This steel involves an air hardening process, as opposed to the more common liquid cooled tempering of other blades. As such it is stronger and less brittle than other industrial steels, so would be more suited for outdoor usages in colder climates with a 25° - 30° bevel angle.) Its high Chromium content allows for greater rust resistance over that of other Carbon blades.

Hope that helps.

Permalink Reply by Pat T on September 13, 2010 at 10:35

That helps a lot! Thanks!!

I'm asking because I was thinking of buying either a Spyderco Stretch in ZDP 189 or a Spyderco Gayle Bradley Carbon Fiber in CPM-M4.

I also have a Benchmade Nitrous Stryker in D2 and I wanted to find out if I could EDC it. I'm concerned about it not being a stainless steel because it misses the amount of chromium needed to be such a steel by 1%.

Permalink Reply by Alexander Noot on August 28, 2014 at 3:18

Steel is a complex question....let me copy something tat I just wrote on another forum. I hope it helps:

Allright, let's start by a very basic approach. I see that hasn't been done yet in this thread. Everyone is throwing out recommendations based on personal experience but there's very little actual information to teach the guy about steels.

First of all you should know that the quality of a blade is made up out of three components:

1) Steel
2) Heat treat
3) grind

You can have a great steel and excellent heat treat but a poor grind for your application then you'll have a badly cutting blade.
If you have a great heat and grind treat but a poor steel then you'll have a blade with bad edge retention or a fragile blade.
If you have a great steel and great grind treat but a poor heat treat then you'll have once again what's mentioned above.

So once we've gotten that out of the way lets talk steel.

Steels are generally a compromise between different things people want out of it:

• Corrosion resistance (stainlessness)
• Edge retention (how well will it STAY sharp)
• Ability to get a fine edge (the grain of the steel/carbides etc that determine HOW sharp you can get an edge)
• Toughness (how much abuse can it take before it'll permanently deform or break)

All of these factors are also influenced by the type of heat treat they get but let's not delve too deep into that right now.

Now like I said it's always going to be a compromise. You want a tough blade that's going to keep a great edge and can be very sharp? Maybe you'll have to choose a steel that's not as corrosion resistant (Like M4 or the earlier mentioned M2).
You want a blade that's tough and corrosion resistant but it doesn't have to be very abrasion resistant (edge retention) maybe you'll have to select 440B (like they use in Randall Knives).

So the real question is....what's important to you? Some steels do this compromise better than others. M390 (mentioned in the Ritter Griptillian by Benchmade) does an excellent compromise and excels in Edge retention, corrosion resistance and a fine edge. And since it's a smaller blade it might not be so bad that it's less tough. (Although EVERY well heat treated blade is tougher than most people tend to believe even in the more brittle steels).

D2 is very good for keeping a working edge (as is S30V) although it's not great at taking a very fine grained edge (which is why it's never used on razors) and it's decently corrosion resistant but not great. (It's also cheap....but that's not really an attribute of the steel...more one of the market because it's produced in such massive quantities.)

If you want something easy to sharpen that'll take a screaming edge but isn't very corrosion resistant one of the "Tool steels" (some of which are carbon steels, some are semi stainless) like A2, O2, 1095, 1084, 5160 or 52100 might be great.

So the real question before we can answer yours on what steel you should get is:

What are the qualities that you're looking for?

Also....your budget helps...because some steels are pretty hard to obtain in an economical package...the M390 Ritter grip is an exception to this. Normally M390 is only found on more expensive knives similar to things like S110V (currently available in the Spyderco Manix for a fair price), ZDP-189, S90V and several others.