STATISTICAL-ANALYSIS OF LUBRICANT PARTICLE-SIZE EFFECTS ON FERROUS P M ALLOYS/

Ferrous powder metallurgy is among the largest commercial activities i n P/M and ferrous alloys have been studied widely in terms of alloying effects and sintering environments. One major processing step that ha s been ignored in general is the lubricant effect on compaction and af ter sintering. Several prior studies compared different lubricants, su ch as zinc stearate and ethylene bisstearamide, but no study has evalu ated quantitatively the role of lubricant particle size. This study ev aluated statistically a 3(4) matrix using green and sinter response va riables to isolate the lubricant particle size effect. The statistical analysis assures credibility of the reported results. Three ethylene bisstearamide lubricants, three loading levels, three compact pressure s, and three ferrous P/M alloys were selected for the basis of the exp erimental matrix. The study concluded that a statistical difference ex ists for measured response variables, including dilation, hardness, an d density. The differences are small, however for most scenarios. The results indicate that lot-to-lot variations in lubricant particle size will not effect sintered properties significantly.