Optimisation of Powder Compaction to Improve the DimensionalCharacteristics of PM Steel Parts

摘要

Considering the conventional process involving the three main steps of powder preparation, cold compaction in rigid dies, and sintering, the dimensional characteristic of PM parts are mainly determined by the compaction step and their precision depends on the compaction tools and on the compaction parameters. This work aims at studying the powder compaction to improve the homogeneity of density and the dimensional characteristics without detrimental of productiveness. The study is focused on a pulley showing a quite complex shape and strict dimensional requirements. The material used is MPIF FC-0205-35, which is compacted by a 200 tons press. The reference compaction conditions are those used in the standard production. The dimensional characteristics are evaluated using a Coordinate Measuring Machine (CMM). Measurement and data processing procedures are defined according with ISO-GPS standards. The distribution of porosity is determined by Image Analysis on metallographic specimens.