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Here is a new question about the making of Japanese knives (you can find the first two here and here).

According to many sources, the best Japanese knives are made in a traditional way with forge welding. However, I learned that forge welding is only for iron and low carbon steel, while the best knives are made of stainless steel (high carbon).

Would there be a way to heat stainless steel blades to melting so that they can be hammered using this forge welding, or should more advanced welding techniques be used? If so, could you give me an example?

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    $\begingroup$ From en.wikipedia.org/wiki/Forge_welding : "Since the critical temperatures are affected by alloying agents like carbon, steel welds at a lower temperature-range than iron. As the carbon content in the steel increases, the welding temperature-range decreases in a linear fashion." $\endgroup$
    – Jon Custer
    Apr 13, 2022 at 13:27
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    $\begingroup$ So their must be another reason why the welding can't be done... seems like I mixed up 2 elements $\endgroup$ Apr 13, 2022 at 14:04

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There is no melting in forge welding ; melting would be a large error. Two solid surfaces are pressed firmly together and reheated; at high temperature, diffusion improves the bond. Damascus and samurai blades are similar, layers of high carbon and low carbon steels folded several times with reheating for diffusion bonding producing effectively a medium carbon steel. Long ago iron came 2 ways; strong ,brittle cast iron, or soft ductile very low carbon wrought iron. The technology did not exist to produce strong tough medium carbon steel. The forge welding of high and low carbon was a good step but the relative high cost of man power mostly limited it to high value products like blades. I am unaware that the process was ever used for chrome stainless cutlery steels. I expect it could be done as a hobby, but certainly not a practical process to make a blade. It is a bit of catch 22, with 13% chrome in steel very little carbon will produce some hardening. So ordinary 410 with 0.15% carbon will harden enough to make a fair blade. To get 410 that won't harden ,you need to pay a premium for 410 S or, 409, or 405. So it will be an expensive hobby.

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    $\begingroup$ Seems another person wants to join the secret society of metallurgy. $\endgroup$ Apr 13, 2022 at 16:36
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    $\begingroup$ I see, so when producers say "my japanese knives are 100% traditionals" they can't say the truth since there is 1,7% of carbon in their blade ! $\endgroup$ Apr 13, 2022 at 16:56
  • $\begingroup$ I should add you in my report as co-author of my work ^^ $\endgroup$ Apr 13, 2022 at 16:56

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