29.6.2009 Pressing & Sintering

Performance of Mixes With New Lubricant System Based on Chromium Alloyed Powders

Chromium pre-alloyed powders are used in an increasing number of PM applications. These pre-alloyed Cr-powders are attractive as they combine high mechanical strength with cost effectiveness. However, due to the solution hardening effect of the pre-alloying elements, mixes based on pre-alloyed powders obtain lower compressibility compared to mixes based on pure iron powders. Therefore, Cr alloyed powders can be more demanding to compact and require more efficient lubricants. The search for higher performance PM components calls for higher density of the sintered materials. To achieve this, a lower amount of lubricant is a prerequisite. To obtain sufficient lubrication, also at a lower amount of lubricant, heating of the tool die is an attractive approach. A new, highly efficient lubricant system for demanding applications has been developed. In this paper this new lubricant system is compared to amide wax as lubricant in mixes based on chromium alloyed powders. Data of the performance of the different mixes during compaction of components under production conditions is presented. Improved mechanical properties from the increase in density are also reported.