| 摘要 |
The present invention relates to an improved method of making submicron cemented carbide cutting tool inserts consisting of tungsten carbide and cobalt by the conventional methods wet milling of powders of WC and Co and conventional grain growth inhibitors to a slurry, drying said slurry to a powder, uniaxial pressing in pressing tools of the powder to bodies of desired shape and finally sintering. During sintering, inserts of this type of cemented carbide generally shrink more in the direction parallel to the pressing direction than in the direction perpendicular thereto. As a consequence, the pressing has to be done in special tools or the inserts have to be extensively ground after sintering both alternatives leading to increased production cost. According to the invention it has been found that for a cemented carbide with a Co-content of 7.5-25 wt% this disadvantage can be eliminated by using WC powder with an FSSS grain size, dWC, of less than 1 mu m and a Co powder with an FSSS grain size, dCo, such that the ratio dWC/dCo is 0.75-1.5. |
