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Old 07-13-21, 03:47 PM
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3alarmer 
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Originally Posted by Mad Honk View Post
Tripple Alarmer,
Your fascination with fire and flames has me wondering about you?? Har! I am not so sure that going through the annealing process and then ramping the temperature back up to oil quench them is a wise thing. They are hardened to start and all that happened was to polish off a bit of damaged metal. Smiles, MH
...I was a blacksmith long before I started squirting water on flames.

Yes, generally speaking, parts made from steel that requires machining are often made from the steel before it is hardened. Things like hub cones, that need to bear some impressive impact loading from time to time, are usually made by a process of case hardening. You don't heat and quench them, which would make them hard but somewhat brittle. Or do nothing at all if the steel is low in carbon content. You pack them in a compound that contains a lot of carbon, and bake them at a controlled temperature, in an attempt to make the surface hard, while still keeping the interior flexible. I'm not sure not all axle cones get this any more, but I am pretty sure the better ones used to.

It's not an especially sophisticated process, and one of the old case hardening compounds was mostly hoof trimmings. And it usually doesn't harden the steel very deeply....it's more of a surface treatment. Which is why polishing out the cones you have is possible, and I see a lot of how to do it's on the internet. But I always wonder about it as a practical matter, in terms of how long they last. ONce you get down past that hardened surface, you're just back to regular old steel. Still pretty hard, but not nearly as durable as a bearing surface.

The reason I mention it at all, is that improper metallurgy in manufacturing these cones originally, has often arisen in the speculation over all the premature failure.
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