Die wall lubricated warm compaction behavior of non-lubricant admixed iron powders

Abstract

The phenomena of die wall lubricated warm compaction of non-lubricant admixed iron powders were researched, and its mechanism of densification was discussed. Water atomized powder obtained from the Wuhan Iron and Steel Corporation was used. With compacting and sintering, compared with cold compaction, the density of warm compacted samples increases by 0.07 – 0.22 g/cm³ at the same pressed pressure. The maximum achievable green density of warm compacted samples is 7.12 g/cm³ at 120 °C, and the maximum sintered density is 7.18 g/cm³ at 80 °C. Compared with cold compaction, the ejection force of warm compaction is smaller; the maximum discrepancy is about 7 kN. The warm compacted mechanism of densification of iron powders can be obtained; heating the powder contributes to improving plastic deformation of powder particles, and accelerating the mutual filling and rearrangement of powder particles.

Keywords

powder metallurgy / warm compaction / die wall lubrication / ejection force / mechanism of densification