Interesting, thanks for your comment - I'll be honest and say I know very little about Japanese sword manufacture. You have prompted me to Google but the info. I've found seems to suggest clay tempering. I'd love to know more - I you can suggest any websites with accurate information about this topic, I'd be very interested. Cheers :-)
Katana were coated in clay prior to final heating, with the clay being thicker on the spine and sides and becoming thinner towards the edge. This technique produces differential hardening when the blade is quenched, creating a very hard, martensitic edge while leaving the spine and body of the blade consisting mostly of pearlite and ferrite. The differential densities of the microcrystalline structures is responsible for the characteristic gentle curvature exhibited by these blades, and the transition between phases is evident in an irregular pattern running the length of the blade known as the hamon.
@@davelivesay6711 You guys are talking about different things. The multi-layered katana with different amounts of carbon in the steel used to form the blade vs the core "backbone" of the sword are techniques that apply specifically to swords. The katana also uses work-hardening to get the crystals in line and strong but flexible. But they *also* quench and temper their steel. All of these techniques are used when making swords (and any other metal object in modern times!!)
Thank you so much for this video. You have answered many questions I have had for so long!
Thanks for sharing this very clear and informative clip. It's great.
Very helpful. Thank you
3:38 Smaller GRAINS and Larger GRAINS or crystals?
Very helpful content thanks :-)
Srsly... Kata? Japanese never used tempering on their katanas. At least historical. It was Europeans wo done that.
Interesting, thanks for your comment - I'll be honest and say I know very little about Japanese sword manufacture. You have prompted me to Google but the info. I've found seems to suggest clay tempering. I'd love to know more - I you can suggest any websites with accurate information about this topic, I'd be very interested. Cheers :-)
Katana were coated in clay prior to final heating, with the clay being thicker on the spine and sides and becoming thinner towards the edge. This technique produces differential hardening when the blade is quenched, creating a very hard, martensitic edge while leaving the spine and body of the blade consisting mostly of pearlite and ferrite. The differential densities of the microcrystalline structures is responsible for the characteristic gentle curvature exhibited by these blades, and the transition between phases is evident in an irregular pattern running the length of the blade known as the hamon.
@@davelivesay6711 You guys are talking about different things. The multi-layered katana with different amounts of carbon in the steel used to form the blade vs the core "backbone" of the sword are techniques that apply specifically to swords. The katana also uses work-hardening to get the crystals in line and strong but flexible. But they *also* quench and temper their steel. All of these techniques are used when making swords (and any other metal object in modern times!!)