THREAD ROLLING DIE AND SURFACE TREATMENT METHOD FOR THREAD ROLLING DIES

摘要

In a thread rolling die, which is a tool for rolling threads and the like, a primary hard film (C1) with a high degree of hardness, consisting of an electrode wear melting substance or a reaction product thereof is formed on a rolling edge face (Wb) by a primary discharge surface treatment; a secondary hard film (C2) made self-lubricating by a secondary discharge surface treatment is formed over it; and the rolling edge face (Wb) is thereby coated with the hard films of multi-layered structure of different materials.