Cold Forged Armor vs. Quenched and Tempered Armor


Feb 2019
Lost in space.
Given if both are made of steel of identical chemical composition, how does cold forged armor compare to armor that is hot forged, quenched and tempered? Would a low temperature stress relief/recovery anneal improve the properties of cold forged steel armor? If so, by how much?

Dan Howard

Ad Honorem
Aug 2014
Are you talking about modern mild steel or bloomery steel? They can't be worked the same way.

Matthew Amt

Ad Honorem
Jan 2015
I think you're getting into technicalities that are way over my head, but you might have to get more specific about your alloy. As I understand it, some can be worked cold much more easily than others, while some gain much more benefit from quenching and tempering.

My advice: Get thee to the Armour Archive! There you will find some VERY experienced and knowledeable people who can give you vastly better answers than you might get here.

The Armour Archive • Index page

Good luck!



Forum Staff
Oct 2011
Italy, Lago Maggiore
I work for a corporation where machines forge stainless steel without heat [so cold forging].

We don't use hot forging, but we can enjoy the presence of presses able to produce a pressure of 150, 200, 300, 600, 1,000 or more tons ...

Now, technically [I've asked to our engineers], cold forging allows you to obtain a better aspect [and I have to say that our products are beautiful ...], but it hardens the material. While hot forging allows you to keep the material well more elastic [but the superficial aspect is not exceptional ... so, don't use it for a parade armor!].

We build our molds. So that we do know how hardness of the steel is pivotal [we measure hardness actually and we use particular thermal treatments to change it].

But before of entering a technical discussion [we know how technical or scientific debates go on on Historum ... being an Assistant Moderator I would like to avoid this ...], I go back to a historical context.

Without powerful machines, cold forging in the past was suitable to make a ... railing ...

[a part that, and here I report a real experience with an engineer who made me note something, just hitting with a hammer a piece of metal you make it hot ... it's physics].

So, I do think [I have to check historical source about this, but I'm quite certain] that hot forging was the rule with iron [actually "sweet steel" from a chemical perspective].