Surface Integrity in EDM of Aluminum Bronze with Nickel Powder Mixed Fluid

Abstract

Aluminum bronze which has high corrosion resistance, high strength and easy castability is recently expected as a new plastic mold or a shell mold core material in place of steel conventionally used. On the other hand, it is reported that the EDMed surface with metal powder mixed fluid has smaller surface roughness and higher resistance to corrosion. From these points of view, EDM characteristics of aluminum bronze were experimentally investigated in the first place. Then, EDM with nickel powder mixed fluid for smoother surface roughness and higher surface integrity was proposed and evaluated. Main conclusions obtained in this study are as follows:
(1) The metal removal rate in EDM of aluminum bronze is approximately the same as that of steel, and no electrode wear EDM is possible.
(2) The EDMed surface with nickel powder mixed fluid has a smaller surface roughness than that in conventionl EDM with kerosene type fluid.
(3) Resolidified layer containing nickel can be generated and the thickness of the layer becomes larger and uniform with an increase of nickel powder concentration in machining fluid.
(4) The EDMed surface with nickel powder mixed fluid becomes harder than that with kerosene type fluid and it has high resistance to sand abrasion.