Annealing/Heat treating

[mhefner@zoominternet]

I have often heated a blade in a home made furnace, quenced it, and had it crack. I think it is because I only heated the blade til it was cherry red but the handle portion was still dark.
My question is... should I heat the entire blade til it's cherry red and not magnetic?
Thanks,
Mike

 

[silver_pilate]

What type of steel? What type of quenchant? Do you know your temperatures?

Many things can cause a blade to crack with the quench: mismatched steel/quench, overheating (could be your problem if you don't have temp control), stress risers in the design, uneven heating/temps throughout the blade (another possibility), uneven grinds, lack of normalizing prior to hardening (another possibility)....etc.

Give us a bit more info, and maybe we can zone in on the problem.

--nathan

 

[hathegkla]

I'm still new at this and cracked my first couple blades from overheating (no temperature control). once I turned my forge down a little the problem went away. but using water for an oil quenching steel will also do it.