Contact fatigue of TiCN coated sintered steels

Abstract

Investigation was focused on resistance of Astaloy CrL type sintered material to contact fatigue. The material in two versions (0·3 and 0·7 wt-%C) was covered with TiCN coating. The results show that resistance to contact fatigue increased substantially, up to the value of about 3410±90 MPa. This increase was influenced primarily by the properties of coating. In this case, the impact of the matrix was of secondary importance. The results obtained in the evaluation of life in terms of contact fatigue were confronted with those of the microscopic observation of generation and propagation of cracks leading to the formation of pitting, as well as with other tests. It describes the impact of contact fatigue stress to changes in the material at the point of application. A special section is devoted to the use of finite element method (FEM) for simulation of the Hertzian stress and changes during contact strain.