A question for smiths or metallurgists

[Bryan Burns]

Notice the difference in color on the two portions of this ax head. This is after a vinegar soak and it's a phenomenon I've observed before on edge tools after a vinegar soak. Am I right in assuming this is because of tempering and hardening of the blade section?

 

[hangfirew8]

That's just the Hardening. Tempering will affect the entire ax head.

 

[HanShotFirst]

Appears to just be hardening. You want he edge harder than the rest of the axe. Sometimes the edge is spot hardened like yours is showing. Sometimes during the forging process a different grade of steel is sandwiched into the middle section to give the best of the best. Yours appears to just be spot hardened though.

 

[rsanter]

Yes....


Bob