Powder metal mixture including micronized starch

摘要

A powder metal mixture comprises a lubricant powder conventionally used to produce powder metal parts in combination with a modified lubricant. A lubricant conventionally used to compact and sinter a chosen powder metal mixture is modified by adding to it starch particles smaller than the average metal particle, and optionally, micronized cellulose fibers in so small an amount that the modified lubricant is present in an amount less than 2% by weight of the mixture. The Hall apparent density and the Hall flow rate of a powder metal mixture made with the modified lubricant of starch or (starch+fibers) remains within the ranges deemed desirable for production of compacted powder metal parts. Using the modified lubricant in lieu of the conventional lubricant increases green strength of a part made by compacting the mixture and improves dimensional conformance.