Chisels, screwdrivers, prybars, sockets, drill bits, springs, gears, valves, etc, etc, etc. Industrial HT certainly does not assume one inch thick sections for a massive amount of steel items.
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True. But many heat treat guides assume that dimensional stability and avoiding cracking are a high priority and therefore may not attempt to maximize properties that maximize edge retention in some complex steels. I can't think of any manufactured part where the heat treat is more critical than it is in a knife simply because a knife edge
will eventually fail in one of three ways in normal use, so obtaining every ounce of potential (for this application) out of the steel really matters. To me it stands to reason that a heat treat optimized for the shape and application of a knife is not readily available for all the knife steels, though I'm sure it is for some.
As I stated earlier, the heat treating suggestions for D2 (as an example) from the manufactures and in the heat treater's guide do not give a "recipe" optimized for a knife application. The steel is designed to retain austenite, which is not good for most knife applications. The heat treat guides do go into cryo and austenitizing temperatures and multiple high temperature tempers to convert some retained austenite, but fundamentally stabilized retained austenite is viewed as a good thing, but generally, in a blade, it is not. This might lead you to believe that D2 is a poor choice for a knife steel, and for certain, when done poorly it takes a lousy edge and keeps it forever. But when a knife maker is using an optimized heat treat, you will find that D2 has an unusual combination of good toughness, good corrosion resistance, and good abrasion resistance that makes for very outstanding fine edge performance in many applications.
The original premise that I disagree with is that all the information a knife maker needs to make a fully optimized heat treat for his knife is available in literature and he simply needs to program his digital furnace accordingly. This may be true for the simple steels, but it is not true for the complex steels. The metallurgical principals are out there for a knife maker to read and try to understand what is happening inside the steel, so there is no magic or special voodoo. But I believe it is not
hype for a knife maker working in a complex steel to "brag" about nailing their heat treat. It is an accomplishment, and it is relevant.
To me knifemaking is like music or any other artistic endeavor. If you produce a superior product, that comes first in my book. It is different when a person is producing stuff of marginal or questionable quality and has quirks to boot...lol Shiva seems to have gotten the scary sharp part down pat from what I have heard.
