Improvement of Press Metallic Mold by Low Pressure Plasma Spraying

Abstract

The aim of this study was to determine whether or not a spray technique would be useful in improving the surface of press metallic molds.
A punch was coated with a hard WC-12%Co layer by low pressure plasma spraying, thermally treated, and applied in deep drawing work.
The results were as follows.
(1) Cr and Ni diffusion layers formed at the interface between the top and under layers under vacuum heat treatment at 900∼1100°C.
A Fe layer also formed at the interface between the under layer and the substrate.
(2) Although the hardness of the sprayed layer was lowered somewhat under vacuum heat treatment, wear resistance was improved.
(3) The results of field test of deep drawing work showed that the combination of the spray technique and heat treatment should be very useful in improving the surfaces of press metallic molds.