The “optimal” temperature of sintering metal powder hard carbide alloys of tungsten-cobalt

Conclusions

• 1. In the range of sintering temperatures of WC-Co alloys containing from 4 to 15% cobalt, lying approximately between 1400 and 1600°C, there occurs regular, but not very significant, grain growth at the sintering time accepted in practice.

• 2. Within a fairly wide range of investigated temperatures, lying within the above-indicated limits, the changes in density, transverse rupture strength, impact strength, hardness, and wear resistance lie, as a rule, within the maximum error of measurement. Thus, an optimal sintering temperature does not exist, but an optimal (sufficiently wide) range of sintering temperatures does exist. There is no inflection point on the sintering temperature-properties curve, but there is a horizontal segment of appreciable length.

• 3. This leads to the conclusion that within the range of sintering temperatures lying between the temperature securing a sufficient quantity of the liquid phase and the temperature of overburning (both depend on the cobalt content), no effects except grain growth occurs if there is an adequate protection against the action of the furnace atmosphere.