Fatigue design of sintered steel components - Effect of stress concentrations and mean stresses on local strength using the highest stressed volume approach

The increasing implementation of sintered steel parts for highly loaded engine and gear-box applica-tions is accompanied by the need of reliable fatigue design method, especially in the pre-development phase. In most cases necessary characteristic values for the fatigue design of PM components, espe-cially for sharply notched areas, are not available. For a diffusion alloyed sintered steel containing 4% Ni (Distaloy AE) the locally endurable stress ampli-tude for different loading modes and mean stresses will be derived by applying the highly stresses volume approach. The correlation of the locally endurable stress amplitude with the highly stressed volume, defined as Vx = x max, will be estimated for both x = 80% and 90% in order to evaluate both approaches with regard to PM steels. The applicability of the assessment of the local cyclic behaviour by the highly stresses volume approach will be demonstrated for a typical design detail of a highly loaded PM-part. Charact eristic values for the fatigue design of PM-components will be recommended.