Warm compaction is a tech nique,which enhances the green den sity of pressed components by heat ing a powder mix and tooling
to t emperatures ranging typically betw een 90 and 150℃.The gain in densit y achieved by warm pressing compar ed to"cold"compaction is typically from 0.07 to 0.30 g/cm~3 depending on the size of parts,the powder f ormulation and the compaction para meters.However,to take advantage o f this beneficial effect of a mode rate increase of the compacting te mperature on densification,powder mixes must be properly designed to provide good and stable feeding of the die cavity at the processing t emperature to allow consistent par t to part weight and density.Also, the base powder and the admixed el ements must be properly selected t o maximize both the green and sint ered densities while maintaining l ow ejection forces and good part s urface finishes.In particular,the selection of the
lubricant is key in
warm compaction. Tihs paper discusses the behavio r of various powder mixes warm pre ssed under different compacting co nditions.The influence of base ste el powder grade and the amount and type of various additives on the g reen and sintered properties is pr esented.Particular attention is pa id to the influence of lubricant o n green density and ejection force s.