En me baladant sur la toile je suis tombé sur cette marque: Diamond Blade http://www.diamondbladeknives.com/index.asp
Ils ont des trucs plus ou moins jolis, moi j'aime bien celui-là:
Mais le truc qui m'a interpellé, c'est qu'ils utilisent du D2 travaillé avec un procédé appelé Friction Forging : http://www.diamondbladeknives.com/image … cument.doc
J'ai quelques lacunes en anglais mais j'ai compris que le tranchant est forgé et trempé dans la même opération, en utilisant la chaleur produite par la friction d'un outillage spécial.
Il y a même une vidéo qui illustre la chose:
Un extrait du document word cité plus haut (qui contient plein d'autres infos):
WHAT IS FRICTION FORGING® A KNIFE BLADE?
“Friction” Forging® is a localized forging process achieving high, transformation temperatures and high loads against a blade and then employing specialized techniques to achieve a rapid quench. The Friction Forging® is performed on the knife blade in the area that will eventually become the edge. Friction Forging® uses a specially designed tool made from Polycrystalline Cubic Boron Nitride (PCBN), a material second only to diamond in hardness. During forging, the PCBN tool penetrates the blade while rotating, which creates frictional heating. When the tool is fully engaged, it moves along the eventual blade edge, creating dynamic microstructure shearing and the high forging pressures that produce excellent blade microstructures. The speeds, heat and down forces are monitored and controlled by the process computer to ensure the creation of a high-quality blade.
The blade edge is brought up to the transformation temperature by the tool. As the tool moves, the blade material is continuously forged. The combination of thousands of pounds of forging force, tool rotation, and temperatures above the transformation temperature produces dramatic reductions in grain size. The grains are in effect torn apart and reduced in size by the combination of very high pressure and heat. Transmission Electron Micrographs indicate that the grain size is reduced due to Friction Forging from 5 microns in typical heat-treated D2 steel down to 0.5 microns, a superfine “nanograin” size. As the steel is brought up to transformation temperatures while Friction Forging®, the carbides dissolve and go into solution. Because the quench occurs so rapidly, some of the Chromium does not have enough time to reform as a Chromium carbide and is “frozen out” in the ferrite and a stainless zone is created where the Friction Forging® has occurred. This zone is so corrosion resistant that a 10% nitric acid etchant will not etch the processed zone.
The primary benefit of rapid cooling (quenching) is that the higher HRc values are obtained (65 to 68); yet because the grain size is so small and thus tougher and stronger, the brittleness normally observed in steel taken to these high HRc values does not occur. The higher the HRc values, the better the cutting performance and edge longevity—as long as the brittleness issue is managed as it is with Friction Forging®.
C'est bon, vous pouvez jeter vos enclumes et vos vieilles forges a combustible