Process for making, and an article of, porous cemented carbide

Claim 1

A PROCESS FOR MAKING POROUS CEMENTED CARBIDE ARTICLES COMPRISING THE STEPS OF (1) MIXING POWDERED HARD METAL CARBIDE SELECTED FROM THE GROUP CONSISTING OF TUNGSTEN CARBIDE, TITANIUM CARBIDE, TANTALUM CARBIDE AND COMBINATIONS THEREOF IN WHICH TUNGSTEN CARBIDE IS THE MAJOR COMPONENT AND A POWDERED IRON GROUP METAL, SAID POWDERED HARD METAL CARBIDE AND SAID IRON GROUP METAL HAVING A GRAIN SIZE OF LESS THAN 20 MICRONS, (2) MIXING A PLASTICIZING AGENT WITH THE AFORESAID MIXTURE, (3) FORMING SPHEROIDAL BODIES FROM THE PLASTICIZED MIXTURE BY TUMBLING THE SAID POWDERED MIXTURE, (4) FULLY SINTERING THE SAID SPHEROIDAL BODIES INTO SOUND IMPOROUS HARD METAL CARBIDE BODIES HAVING A SIZE FALLING WITHIN A RANGE OF FROM ABOUT 20 SCREEN MESH TO ABOUT 325 SCREEN MESH, (5) PRESSING A MULTIPLICITY OF THE SAID SINTERED BODIES INTO CONTACT WITH EACH OTHER AND HEATING THE SAME TO A SINTERING TEMPERATURE AT WHICH THE SAID SINTERED BODIES FUSE TOGETHER AT THEIR POINTS OF CONTACT AND MAINTAIN THEIR IDENTITIES AS SPHEROIDAL BODIES.