I just put the test piece of Nick's twist in deep cryo and felt I should share what I have so far. Because you fellows have entrusted me with the heat treat, which could spoil all our hard work and time if not done properly, I have decided to not just provide details as they occur but to share my corresponce to Nick (ONLY from me to him) about the test and all things relative to it. Below is my latest email to Nick and will update all us here with final test results tommorow evening.
My email to Nick just moments ago:
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Nick,
The sample is in deep cryo. Just finished snap temper (350 F. / 45 minutes) and after still air cooling I grinded off scaling. Tested 60.5 HRc. I got two tests at 60, two at 61 and two at 60.5 HRc. I call it 60.5.
All I really saw under a 10X eye loop was scaling, no pitting and was able to grind off the scaling to what looks like flat surface under 10X magnification with a 220 grit ceramic belt.
After normalizing twice and still air cooling to about room temperature, I removed the steel from the foil packet and ramped to 1200 F. at a rate that took about 25 minutes and soaked at 1200 F. for 5 minutes (equalize). I then ramped at maximum ramp rate to 1450 F. and soaked there for 5 minutes. My oil temperature was at 138 F. and I am positive I got into quench in slightly less than 1 second. At a bit more than oil temperature I placed in pre-heated snap temper.
Please give me your thoughts about the Rockwell I got after snap temper. I am not experienced with HT'ing 1084 and would like to know if you think I am in the ball park so far. After retrieving from cryo tomorrow we will have an idea of how much retained austenite there may have been after quench.
Thanks again Nick. Please advise as you see best.
Roger
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It has been very pleasant to ask Nick for advise on this matter and he has been concise and careful to expand on areas he may think I am not sure about.
Roger