[Gerald Fa.]

What are the difference between "Hammer Hardening" to "Work Hardening"?

1. Is "Work Hardening" is something that is naturally done in a forge. What I mean ins when working on and forging a tool, armor, and sword rather than just stamped. As for "Hammer Hardening" is when it is done or has the basic shape and hammer in the same spot over and over again to compress and or stretch the iron or steel? Is this right?


2. Are they the same?

I have a 1.5 mm mild steel Sallet helmet that is big time "hammer hardened".

3. Is it recommended for armor? Is it effective?

4. Can something be Hammer harden still be Heat treated? Or would it be applied after something is heat treated?

[Tim Harris]

Hi Gerald,
I can't speak with any authority about armour, but as far as sword blades go, any sort of mechanical hardening would be overidden by heat treating, which resets the physical properties of the metal by altering the micro-structure. Working a heat-treated blade with a hammer isn't going to do anything useful.

As long as it is made of suitable metal, a sword blade gets its performance characteristics from its shape and the quality of its hardening and tempering rather than the way it was made. Mechanically, there is no appreciable difference between a heat-treated blade that has been forged and one that has been ground out of a bar. I hope that answers some of your questions.

[David Cooper]

Gerald
I think the two terms relate to the same thing. Some metals are strengthened/ hardened by being repeatedly deformed. (plastic deformation) Low carbon steel is one of them. I've most often seen this discussed in relation to bronze weapons though. Bronze, copper and silver are often work hardened. Indeed in jewellery and silver work the metal has to be reheated repeatedly to stop it becoming too hard and brittle when working it.

[Vasilly T]

I gotta agree with the above posters. It's probably two different ways to call one process: cold hardening. And as heating resets the physical properties of the metal, it's usually done with mild steel armour, which is hardly affected by heat-treatment due to low carbon content and therefore usually not heat-treated but instead cold-worked.