SURFACE TREATMENT METHOD OF ALUMINUM EXTRUDING DIE, AND ALUMINUM EXTRUDING DIE

摘要

A surface treatment method of an aluminum extruding die having wear resistance and separation resistance is provided. The surf ace treatment method of an aluminum extruding die includes a first nitriding treatment step for forming a diffusion hardened layer 6 containing carbon and nitrogen at a surface layer portion of a die main body 5 by heating and retaining the die main body 5 made of tool steel in a nitriding gas atmosphere containing carburizing gas, and a second nitriding treatment step for forming a compound layer 7 substantially not containing carbon on a surface of the diffusion hardened layer 6 by heating and retaining the die main body 5 to which the first nitriding treatment was executed in a nitriding gas atmosphere not containing carburizing gas.