I'll see if I can dig up some info for you, but hardness is not going to be revealed by the alloy designation as a general rule. The numbers you may be thinking of, like "440C", "1095", "ATS34", "D2", etc. are - for the most part - a scheme for representing what type of alloying ingredients are present in general proportions.<br><br>Hardness for steel is usually expressed on a relative scale - a Rockwell scale. The specific tests to determine hardness vary, but the Rockwell "C" scale is most useful for indicating hardness when we are discussing knives. For example, a knife with a hardness of Rockwell 59C (often abreviated RHC 59) would be usable for many (most) knife tasks, all else being equal. But even the Rockwell C hardness test does not tell us everything about how a knife performs. It is a generally useful measure of some qualities, and within a certain alloy or type of alloy we can extrapolate other material properties by knowing the hardness.<br><br>Mass produced knives, which are probably all of the moderate-cost ones, are usually uniformly hardened all over the knife blade and tang. Some custom knives are hardened to different degrees in different places to take best advantage of the material properties - reducing brittleness in some areas, making it tough in some areas, making it very hard (and hence capable of extremely fine edges) in other areas, and so on.<br><br>Steel that can be hardened (that is, steel with carbon content in a fairly narrow range - stainless or not) is usually heated to a fairly high temperature and then cooled relatively rapidly to make it extremely hard. How it is cooled varies - some are air-hardening, some are water-hardening, some are oil hardening, etc. There are inummerable techniques. At this point, the steel is TOO hard. Then the steel is heated again, but to a lesser temperature. This is properly called "drawing the temper", although common useage has resulted in the phrase "tempering" the steel.<br><br>Mind you, what I just wrote is a huge simplification. The whole process can be (and often is) much more involved. The result is a knife blade that is as hard as the manufacturer wants it, within the material property limits of the particular steel being used. Too hard and it is brittle, like a piece of stress glass. Too soft, and it may not hold an edge very well or may even bend hopelessly with very little force applied to it. It's science in mass production and scientific art in handmade knives (or artistic science...)<br><br>I know this is not answering your question - it's not quite the right question - meanwhile, I will see if I can dig up a partial explanation of alloy numbers for you.<br><br>Spend some time on
this link to learn about steel ASIS numbers. You will need to check the sidebar from time to time (like when you read about stainless steels).<br><br>Hope this helps - go to the blade and knife forums to learn about what all this means when it comes to knives - beware that there are so many good choices now, there are fanatics for every type of steel suitable for knives... <br><br>Tom