Development of a method for producing submicron cemented carbide from a powder obtained by electrical discharge erosion of scrap in oil

The work is devoted to the production of powder by electrical discharge erosion (EDE) in oil from WC-10Co cemented carbide scrap, post processing of the obtained powder and sintering of a submicron alloy from it. As a result of EDE of WC-10Co alloy in oil, a powder with an average particle diameter of 12.7 μm, was obtained. Pyrolysis of the oil prevented the loss of carbon by tungsten carbide and led to an increase in the carbon content of the powder from 5.5% to 8.6%. A technique of heat treatment of the obtained powder in CO2, for the removal of excess carbon (3.1%) was developed. On sintering the powder at 1370 °C, a WC-10Co alloy with a stoichiometric carbon content (5.5%) was obtained, in which plate-like and prismatic WC grains an average diameter of 0.58 μm were formed. The alloy combines high hardness (1520 HV) and fracture toughness (14.6 MPa√m). [Display omitted] •A technique of WC-Co recycling by electric discharge erosion in oil was developed.•The pyrolysis of oil leads to an increase in the carbon content in resulting powder.•Heat treatment in CO2 reduces the carbon content to the required value.•Plate-like grains of WC-Co were formed in the particles during heat treatment.•Recycled alloy have the high hardness (1520 HV) and fracture toughness (14.6 MPa √m).