抄録
On the influence of the amount of Zn-St type lubricant on rapid sintering of sintered steel, we prepared 4 types of specimens with different amount of lubricant. In this experiment, isothermal treatments (I.T) were done at 1223K and 1373K in 90s holding conditions. The purposes of isothermal treatment were delubricanting, degasification, diffusion of graphite and copper, and austenitizing of ferrite. The specimens were finally sintered at 1473K in 60s holding condition. As a result, Cu came to be in liquid phase when IT temperature was over the melting point of copper. This treatment was able to diffuse fully in intergranular and transgranular sites. That is to say, all specimens included lubricant were obtained with high radial crushing strengths (RCS). From isothermal treatment (1373K-90s holding condition) obtaining a good result, we tried to shorten the holding time in IT from 90s to 60s for the standpoint of omitted energy. All the specimens including lubricant were obtained with high RCS values, too. In brief, increase of the amount of lubricant were not influenced for sintering density as well as dimensional change less than 0.2%.
