The desire to produce functional powder metallurgy (PM) components has resulted in higher compression forces during compaction. This in turn increases the ejection stresses and therefore the possibility of failure during ejection. This failure can be caused by sprig back during ejection due to frictional forces that are generated between the powder part and the die walls. In order to predict these factors a stress analysis of the powder part during ejection was done. Due to complexity, finite element analysis was used to model the powder during compaction and ejection. Since the ejection stage is the most critical stage of the PM process, it is essential to understand the factors that determine the survivability of a part during this stage. This work uses experimental data, finite element modeling and reliability analysis to determine the probability of failure of metallic powder components during the ejection phase. The results show that there is an increased possibility of failure during ejection as compaction pressure is increased. This information can be used by designers and process planners to determine the optimal process parameters that need to be adopted for optimal outcomes during powder metallurgy.
High-Nickel Maraging Steel by Powder Metallurgy (Part III)
