02-13-2018, 10:50 AM
(02-11-2018, 09:34 PM)me2 Wrote: Inexpensive stainless steels often have inexpensive heat treatments. This leaves a high percentage of retained austenite, which is soft and gummy. However, it was also easy to get stainless steels not suitable for cutting tools. This combination gave stainless a less than stellar reputation.
Good stainless has been available for a while, 90 years or so. It has higher wear resistance than the low alloy and plain carbon steels like 1095, 52100, O1, and similar steels, though the difference is not large. Several alloys were developed for cutting applications. They behave very similarly to carbon steels. They have carbide sizes similar to low alloy and plain carbon steels, but I have been unable to find grain size data from a reliable source.
The extra chromium in stainless makes stainless corrosion resistant. The minimum necessary is between 10 and 12 percent, depending on the source of information. When a stainless has enough carbon, it combines with the extra chromium to make chromium carbides, which are harder and more wear resistant than iron carbide.
Mr. Me2, what old stainless are you speaking of? This is news to me, and shouldn't be. I certainly don't know of any stainless, old or new, that is as easy to sharpen as plain carbon.
I know by old definition a steel can be considered stainless with as little as 10-11% chromium, but I think that must mean free chromium. I don't know of any steel with that amount of chromium, and I don't know of any steel that is considered stainless (at this time) with less than 14-15% chromium, but there are a lot of variables.
I don't think wear resistance is a very good indicator of edge holding. S30V has high wear resistance, but I don't know anyone who thinks it performs well. Most consider it very hard to sharpen. Most say it needs high refinement, and holds a mediocre edge for quite a while. I've had an S30V Sebenza for a decade, and it's been sharpened a lot (almost ready for a new blade), because I don't care for mediocre sharpness.
I think D2 is a good steel for comparisons. If you read what is commonly written about D2's rust resistance, it's never considered "stainless". With 11-13% chromium, the best I've ever heard is "semi-stainless". I have D2 knives, and they are not very stainless, but it does have very high carbon, so I know a lot of the chromium is tied up in it's very large carbides (which are a recognized drawback).
I have a lot of real world experience with hunting knives. I've been sharpening all sorts of hunting knives for over 40 years, with an emphasis on pre 86 Gerbers and Bark River knives, which I consider benchmarks for production knives. Gerber ran 440C at HRC 58-60, but it seems a point higher to me. Their old M2 is fabulous, and hard. I think HRC 63-64 is fair. It's better than Benchmade's old M2, which was another benchmark of it's own. These knives have appreciated dramatically, and are super collectible, which should mean something.
Obviously, I favor 52100, and I've carried a Bark River in 52100. It outperforms Mike's favored A2 , but maximized with an exact heat treat, it is simply unbelievable. The plentiful real world feedback is stunning. I carry two knives at all times, one of mine, and a high end folder with the best steels. I make comparisons on a daily basis, and I do a Lot of sharpening and BESS testing.