The Effect Of Density, Carbon Content And Microstructure On The Torsion Fatigue Strength Of Sintered Steel

Structural components produced by press and sinter technology are subject to limitations in strength due to the inherent porosity. Hence, the improvement of material properties by heat treatments or surface densification is a crucial step to open up new markets and maintain competitiveness with conventional production routes. While the effect of heat treatments is well reported for densities of up to 7.2 g|cm³, no information is available on the fatigue strength of the pore-free material. Therefore, this work aims to analyse the fatigue properties of molybdenum alloyed sintered steel at different carbon contents, microstructures and densities. This investigation is partly based on the testing of round samples, which are compressed to full density by an additional HIP process. Subsequently, a regression model is derived that approximates the fatigue strength based on the density, hardness and microstructure, which can then be incorporated in a numerical assessment of the load bearing capacity.