Patent ID: 9393611
Filing Date: 2016-07-19
CPC Classification: B21J,B21K,B22D,C23C

Claim Text:
1. A method for reinforcing a die, comprising: irradiating a die material made of a high speed tool steel for hot dies comprising a matrix high speed tool steel, an alloy tool steel for hot dies or a stainless steel as an irradiated object with a large-area electron beam to form a smooth surface modification layer of 2 to 5 μm in thickness by elution of a contained substance in the die material; and subjecting the die material in which the surface modification layer is formed to a sulphonitriding treatment, so as to form a sulfurized film having a thickness less than the thickness of the surface modification layer prior to the sulphonitriding treatment and containing a sulfur compound of the contained substance more than a sulfur compound of a main substance in the die material and, adjacent to the sulfurized film, a diffusion layer of nitrogen and sulfur.