Characterization of High Strength Bearing Steel
High strength bearing steels are developed for very high contact pressures and compressive stresses. Local tensile stresses may however develop phase transformation. A side effect of the high strength is that stresses can become sufficiently large for unusual material behaviour. One such behaviour is solid to solid phase transformation which is dependent on temperature. Not only the phase change but also low temperature creep is also observed where low temperature can be defined as from room temperature to about 150 C. The purpose of the experiments is to measure the amount of phase change under different temperature and loading, and to quantify and predict the risk of creep rupture of existing cracks in a high strength bearing steel.
The work contains experiments and modelling of the crack behaviour at high static loads. The crack propagation and the material creep will be small which places high demands on accuracy in the experimental work and in the crack growth measurements. The measurements uses the potential drop techniques.