There have probably been more nasty remarks and hot discussions about knife steels than any subject other than heat treating. We start out with the belief that there are a great many good steels, and choosing the right one means understanding what you want to use the tool for!
There are a horde of modern steels ... ranging from the not so fine (generic 440) to the simply amazing (Crucible Particle Metals such as CruWear of CMP10V). Their cost, wearing/usage characteristics, and the ease with which they are worked also vary widely. All the variables and possibilities considered, we like L6, 5160, 440C, ATS-34, 440V, CPM10V and VascoWear or CruWear.
Choosing a Steel for Your Application
Too cheap a steel and a terrific amount of work is wasted on a blade that will simply not deliver service that is acceptable to a discerning user. Too expensive a steel usually yields a tool that may last forever, but is too hard to work, too tough to sharpen, or may rust.
Here are some rules of thumb for selecting the steels we like to work with:
A non-stainless steel bearing abt 60 points of carbon and lots of Nickel. Yields a strong, springy, impact resistant blade. GREAT for large blades of some length.
A non-stainless steel bearing abt 60 points of carbon with chrome and nickel. Yields a strong, springy, impact resistant blade. Fine for large blades that do not have to be rust resistant.
Blade must be rust resistant and large ... where a hardness of RC55 would be sufficient because the weight of the tool does much of the work for you.
Blade must be rust resistant, not overly large and it must be very, very sharp. The tool can be sharpened in the field at the end of a days hard use.
Blade must be rust resistant, not overy large, and must be very, very sharp. Sharpening may not be easily accomplished in the field. In other words, used where conditions would make ATS-34 a bit of a pain. 440V is harder to work and harder to sharpen but holds an edge longer than ATS-34. The basic material for blades is also much more expensive than ATS-34.
Blade must be VERY sharp and be incredibly long wearing. Blade will probably be thin in cross section and rust resistance is not an issue. One of the Crucible Particle Metals ... amazing stuff: expensive, hard to work, hard to sharpen, and virtually indestructable.
CruWear or VascoWear
Blade must be VERY sharp and be incredibly long wearing. Blade will probably be thin in cross section and rust resistance is not an issue. CruWear is the Crucible equivalent of VascoWear ... amazing stuff: expensive, hard to work, hard to sharpen, and virtually indestructable. Seems to have slightly better corrosion resistance than CPM10V and is slightly less wear resistant too.
Pattern Welded Steels (Damascus)
Material Properties Material properties of pattern welded blades are derived two ways: 1) the alloys used in making the basic knife stock, and 2) the pattern the into which the alloys were welded.
Pattern welded steel is simply layers of more than one kind of steel forge welded together.
Good pattern welded steels for knives are made from carbon steel and a similar carbon bearing steel that also has nickel or chromium in the mix. (Mild steel mixed with a carbon bearing steel is NOT good for making knives that will actually cut and have some wear resistance!)
There are lots of approaches to this problem, but we frankly like mixing 1084 or 1095 with L6 or 15N20. These combinations result in a steel having about 70 TO 80 points of carbon in the final billet for blade making and great coloring from the nickel in L6 or 15N20. Pattern The pattern affects the resulting blade in two ways. First, the more layers there are at the edge (all other things being equal) the better the knive will cut. Second, the more the blade is built to absorb shock through using the pattern to provide strength the more robust the blade will be.
Thus, fine ladder or twist patterns with lots of layers will cut better than those with a smaller number of layers. A blade made from a serpentine core with chevron twist bars on both sides of the blade and steeled with a high layer count edge will be significantly more resistant to shock damage than will a homogeneous steel blade of similar alloy. (If the welds are all perfect.) All that being said ... Pattern welded blades are prettier than those made of homogeneous steels. They can cut very well, but generally it is hard to beat the cutting ability of modern high tech steels like ATS-34!
Full composite pattern welded blades make for beautiful, strong, sharp, elegant, and expensive works of art! They are expensive because of the huge amounts of material, time, and experience required to make them.