Nicholas,
Just read your last. In metallurgy, you have met your match. Oh, a person can get gods-rotted serious and come so close as to be the same but the reality is, if an ordinary person really wants a full and complete metallurgical understanding, 4 yrs of college, then more, and then more yet is the description of it.
If it's interesting to you, have as much as pleases. If you HAVE to know why to be happy, comfortable, or to function, stiffen up your neck and get a good helmet. To make knives well for the form and steel and design-use is less of an undertaking.
This knife making is a very individual thing. The differences a person finds in making-process is as varied as the individuals, which is to say, totally different. Still, there is a simplicity to it as a person looks at it metallurgically.
The first thing is, "Every steel is different"... a quote by "mete", on various forums, over many years and many times. There is nothing in metallurgy as it pertains to steel that pertains to blades that is more important to understand. A person can actually refine it to "which O1?" and not be joking even a little bit, though the functional differences tend to fall as differences in process...
The second thing is, there are directions. The absolute best for non-denominational base data is Heat Treaters Guide (ASM publication... American Society for Metals). Then, most manufacturers give HT process directions with their steel. (It is an interesting exercise to reference the general and the specifc for O1)
You are going to have to take the directions and though deduction match your processing ability (tools and understanding) to make the steel do what you need it to do. As "every steel is different" so is every processing ability.
Your first post had a list...
1. What does annealing actually do?
2. Same with normalizing - what does it do?
3. How can grain size be reduced?
4. Do you have to forge to reduce grain size? (I only do stock removal)
5. How is steel treated such that it flexes the way Ed Fowler talks so much about and is required to become an ABS smith?
1. I can just hear "mete", "Oh for god's sake, books have been written on what annealing actually does"...
In some ways it makes the element dispersion and the crystal structure even... like it disallows disimilarities of either that might be disadvantageous to various processes (forging, machining, heat treating, etc.)... generically, "soft".
2. Normalizing is equalizing and refining grain size... making all, the same size and of useful size (usually smaller, though not necessarily better the smaller they get... for the use). Steel is more stable (has less strain) and is predisposed to eveness in processing and even change in heat treating as the grains are equal. Steel is tougher as the grains are smaller (smaller has limits of usefulness... beyond, causes structural and/or processing problems... as a generality).
3. Heating to a high austenitizing temperature for the "every steel is different", short of the limit of grain growth for that steel, and cooling in still air equalizes the grain size. Doing this two to three times, at lower austenitizing temperatures for the following cycles, refines the grain size. "mete" calls it smallerizing, I think... =]
4. As has been said, but in other words... nope!
5. One way is differential quenching where only the near-cutting-edge is hardened (only part of the width of the blade is immersed in quenchant and only part of that part is fully hardened, leaving the rest significantly less brittle ~ and significantly less strong and more prone to bending/plastic failure). Another way is to differentially temper (fully harden, fully temper to desired hardness, selectively draw/temper by applying heat to the spine to reduce it's HRc while keeping the near-cutting-edge at the initial tempered hardness... various methods... search and you will receive).
There is madness to the method. One can lay claim to general usefulness of differential tempering as use of the knife goes beyond common. One has a hard time finding usefulness in differential quenching, by comparison. The ABS testing reqirements could be passed with either method, and I believe could be passed with a fully hardened blade... a person would have to work on the later, though.
So, there's one more beer in the fridge and it's crying to be out of the cold and into the six pack holder with it's MT brothers and sisters... right after that, I'm getting into my jammies and calling it a night... =]
Mike
Well, maybe one more thing... "mete" one time said, in relation to the various forging through heat treating processes (this is a paraphrase)... what you get is either coarse grained perlite, fine grained perlite, coarse grained martensite, or fine grained martensite.
