HT & Annealling ?

Tommegow

Tommegow

Joined
Dec 16, 2004
Messages
678
Displaying my lack of understanding of metallurgy.
I have a bunch of new Sawmill bandsaw blade. Analyzed as 1075.
I have been working on it as is. I HTed a piece at 1450 oil quenched and tempered at 400 degrees.
I read it needed to be annealed at 1700 degrees.
Did I actually HT my test piece?? If it is already HTed and I heat it to 1450
did I really do anything? I am clueless and confusing myself :confused:
 
At least you spelled it correctly. If you wanted to work the blade [cut and grind] soft you would first anneal . But NOT at 1700 F !! Anneal at 1450 F and cool slowly in ashes.Now you can work it. Then harden and temper as you have ,1450 F, quench in a light oil. temper at 400 F.
 
Thanks Mete! I heated a small roll of it to 1700 in the HT oven at school.
dropped temp 50 an hour then shut the oven off to cool slowly.I will go back in the a.m. and take it out. Did I ruin this batch at 1700??
 
Tom, it will have grain the size of New Jersey from being heated so far above "critical" . You can try and recover it by taking it through several "normailzing" cycles. Heat to 1450 and allow to cool in air several times to dead black but still quite warm. Then take it through an anneal cycle but only up to 1450 then slowly cool. It might be ok again by that time if it's not one big ball of oxide when you open the oven tomorrow.

If you have a bunch of it that hasn't had this nuke-job, I'd just chalk this up and move on. Might be a good opportunity for some learning experience. Heat a piece up to 1450 and quench then smack in a vice hard to break (no temper, keep it dead hard.). Observe the grain. Take it through the normalizing cycles and repeat breaking a new test peiece. Good demo of the effect of overheating and the benefit of normalizing. It'll go from looking like grey grains of sand to very fine looking. It can be pretty dramatic.

Just my take on it. Someone else may have a lot better advice.
 
Mike
I have plenty left and it was free, so chalk it up I will.
I can play will the mess as well
Thanks
Tom
 
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