Fatigue design for powder metallurgy
This paper presents design relevant material data like S-N curves, effect of notches and mean stresses and fracture mechanical properties. The influence of different manufacturing parameters on the fatigue properties of sintered steels is discussed. The necessity to determine material properties, under different loading modes, is outlined against the background of different service conditions and component geometries. The fatigue design starts out by determining the local stresses and their distributions in the most critical areas of the parts due to the loading. For the fatigue life assessment the local stresses have then to be compared with adequate material properties in order to evaluate design, material and technology selection and to decide whether production can be started or further optimization is necessary. Within the design procedure, the importance of the scatter of material properties, manufacturing and service loading which determine the safety margin is also discussed fr om the standpoint of component reliability and economy. The design procedure for PM components is illustrated by an example.