Interestingly, in the aerospace industry we can use shot peening to induce surface hardness and shape the thin aircraft skins. You fire thousands of little ball bearings at the skin which hardens the surface and bends the material to the desired shape. So when in use the outer shell is work hardened and has compressive stresses to resist fatigue, sort of like firing thousands of micro-hammers at the aircraft shell.
This is super fascinating! Thanks so much for sharing Jacob. I find this insight into the modern aerospace industry gripping because you can see a synergy between material use across 500 yrs of history. Same principle and same equivalent industry but 500 years of advancement and engineering between. So cool
And that is why mild steel with a fracture toughness of 237 kJ/m2 is an analog for slack-quenched medieval medium carbon steel, and not medieval air-cooled medium carbon steel, as has been suggested by some individuals.
I think they would have hot worked everything historically because of the fibrous nature of wrought iron and bloom steel. If you want to give it a go maybe I can give you some wrought iron at the abbey.
Correct. Slag will also reduce the ultimate compressive strength of the work hardened material significantly. It's only a benefit to us when we use modern slagfree steel.
@@NoBSSurvival I know. I didn't misunderstand you. I just wanted to add that there is no benefit doing it with wrought iron and bloomery steel if it could be done because of slag.
The quality of the steel itself adds a whole different aspect to the discussion. As you say, historical steels of a lower quality of consistency and a potential to delaminate would not benefit necessarily from work hardening. Depending on the piece in the harness it probably received a similar treatment but I believe we have evidence that they did try to harden the steel by quenching on most occasions altho most likely with limited success due to the variability of carbon content. As pontetef out, once heated most or all of the workhardening benefits are made redundant
I've seen 3D simulations of the lattice dislocation slips as something is work hardened. In the experiment it was only shear strained in one direction for analysis purposes but in the model, the web and tangle of the dislocation filaments quickly consumed the whole volume and tangled amongst each other right away, even with the one dimensional strain. It was amazing to see. So from that, I gather that hammer hardening does a similar thing but possibly even better. Since each hammer blow creates a good quantity of dislocations but also creates its own sort of macro grain boundaries that really tie up the dislocations and locks them in place, thus making it stiffer and less ductile. In a twist, those hardening "spots" from the hammer looks to also prevent it from becoming too brittle. Really cool and intricate microphysics going on.
Very nice video this week boys. Very helpful and definitely informational thank you so much. Can't wait to see more videos soon. Keep up the great craftsmanship and hard work my friends. Forge On fab On. Weld On. Keep making. God Bless.
I did some years of making armour. I always used mild steel due to the limitations of my workshop. Once I managed, by accident, to harden mild steel by quenching it in brine ( my goal was just to create a distorted look for a Uruk Hai armour). It came out very tough, hard and springy...
Curious and sounds like an awesome project however I am fairly sure the metallurgy does not change no matter what solution you quench it in since thermal hardening is dependant on a hardenable amount of carbon content
Interestingly, in the aerospace industry we can use shot peening to induce surface hardness and shape the thin aircraft skins. You fire thousands of little ball bearings at the skin which hardens the surface and bends the material to the desired shape. So when in use the outer shell is work hardened and has compressive stresses to resist fatigue, sort of like firing thousands of micro-hammers at the aircraft shell.
This is super fascinating! Thanks so much for sharing Jacob. I find this insight into the modern aerospace industry gripping because you can see a synergy between material use across 500 yrs of history. Same principle and same equivalent industry but 500 years of advancement and engineering between. So cool
And that is why mild steel with a fracture toughness of 237 kJ/m2 is an analog for slack-quenched medieval medium carbon steel, and not medieval air-cooled medium carbon steel, as has been suggested by some individuals.
I think they would have hot worked everything historically because of the fibrous nature of wrought iron and bloom steel. If you want to give it a go maybe I can give you some wrought iron at the abbey.
Correct. Slag will also reduce the ultimate compressive strength of the work hardened material significantly. It's only a benefit to us when we use modern slagfree steel.
@@eirikronaldfossheim sorry but what I meant was that working wrought iron too cold makes it break apart.
@@NoBSSurvival I know. I didn't misunderstand you. I just wanted to add that there is no benefit doing it with wrought iron and bloomery steel if it could be done because of slag.
The quality of the steel itself adds a whole different aspect to the discussion. As you say, historical steels of a lower quality of consistency and a potential to delaminate would not benefit necessarily from work hardening. Depending on the piece in the harness it probably received a similar treatment but I believe we have evidence that they did try to harden the steel by quenching on most occasions altho most likely with limited success due to the variability of carbon content. As pontetef out, once heated most or all of the workhardening benefits are made redundant
If it ain't Rickert from the Band of the Hawk!
I've seen 3D simulations of the lattice dislocation slips as something is work hardened. In the experiment it was only shear strained in one direction for analysis purposes but in the model, the web and tangle of the dislocation filaments quickly consumed the whole volume and tangled amongst each other right away, even with the one dimensional strain. It was amazing to see. So from that, I gather that hammer hardening does a similar thing but possibly even better. Since each hammer blow creates a good quantity of dislocations but also creates its own sort of macro grain boundaries that really tie up the dislocations and locks them in place, thus making it stiffer and less ductile. In a twist, those hardening "spots" from the hammer looks to also prevent it from becoming too brittle. Really cool and intricate microphysics going on.
very informative
your channel really needs to blow up man, you and your fellows are extremely talented!
Thanks Joel, I alas learn something from your videos.
Very nice video this week boys. Very helpful and definitely informational thank you so much. Can't wait to see more videos soon. Keep up the great craftsmanship and hard work my friends. Forge On fab On. Weld On. Keep making. God Bless.
work hardening - more dislocations. That makes it so that the material can not deform as easily. Nice metalwork skills.
I did some years of making armour. I always used mild steel due to the limitations of my workshop.
Once I managed, by accident, to harden mild steel by quenching it in brine ( my goal was just to create a distorted look for a Uruk Hai armour). It came out very tough, hard and springy...
Curious and sounds like an awesome project however I am fairly sure the metallurgy does not change no matter what solution you quench it in since thermal hardening is dependant on a hardenable amount of carbon content
Do you get a lot of thumb pain hammering with your thumb on the back of the hammer like that?
Not at all. The force applied is not great in armouring but control is paramount