Simple question?

I don't understand the question.

Seems to me you would quench after having reached austenitizing temperature.
 
I think I understand were you are coming from. You want to know what pre-HT regime you should use. There is no "best" answer to this but I'll give you my take on it. I want to work(drill, grind, file, etc) the steel in its most workable state, which is usually an annealed state. I also want to refine the internal structure until it is fine, uniform with evenly distributed carbides. In layman's terms(which is all I can offer, really) this sets the steel up for an "easy" conversion to austenite.

I am a forgin' freak, so along with setting up for heat treat, I have to make sure I fix anything I may have screwed up during the forging process(hopefully I didn't mess up the steel too badly). I start with a normalization cycle. Heat to 1600F(bright red) and cool to black, quench. Then some refining cycles. Heat to 1500F(medium red) and cool to black, quench... heat to 1500F again and quench from red. At this point I will either run one more cycle from 1450(dull red, just passed non-magnetic) to black, quench OR fully harden from 1475F and spheroidize. Spheroidizing is kind of like a super-anneal(I know Mete will bite me for saying that), where you heat the steel enough to draw the carbon from the matrix into little clusters(spheroids). Of course, my explanation is probably simplified to the point of being wrong. This is achieved by heating the steel to a subcritical temperature of around 1250-1300F and letting it cool slowly over the course of several hours. What you are left with is ferrite in a very soft state. Easy to machine and primed for the final heat treat and because you remained sub-critical, there was no effect on the size of the grain. (you can get a similar "low-tech" result if you heat the blade to a very dull red 3-4 times, letting it go black each time.)
 
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12345678910 said:
I don't understand the question.

Seems to me you would quench after having reached austenitizing temperature.
Click to expand...
+1

You would quench the blade after shaping it. You need to heat it to the appropriate austenizing temperature, then (usually) quench (cool) it rapidly enough and to a low enough temperature to form martensite with a minimum of retained austenite. This will give you a hard, brittle blade. At that point you would temper it back to the desired hardness.
 
Thanks a bunch guys.

Thankfully Rick somehow understood my convoluted question. That was exactly the confirmation I needed. I thought I was leaving a step out, but apparently not.

I was having a hard time accepting that my full tapered tang was strong enough, and I thought there might be a step that would refine the grain, but leave the steel harder than normalization. At least I was hoping for one.

Thank you very much for your time, especially you, Rick.
 
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