Abstract
High end applications often require high strength materials especially regarding the fatigue limit. It is still an open question what the highest fatigue limits are and how to increase them further in high strength steels. A thermomechanical treatment (TMT) in the temperature range of maximal dynamic strain ageing is an auspicious way to increase the fatigue limit of bearing steel SAE52100. Successful attempts have been published for various materials states. The present investigation deals with the influence of non-metallic inclusions on the fatigue limit and the possibility to increase the fatigue limit by TMT. The fatigue limit of high strength steels increases by reducing the size of the non-metallic inclusions during steelmaking. We found that TMT increases the fatigue limit of a high strength materials state only in cases in which the non-metallic inclusions are the starting points of the fatigue cracks. In the case of high cleanliness of the steel the origin of the fatigue cracks may be at any position in the matrix. If there are no critical non-metallic inclusions a TMT did not increase the fatigue limit further. The reasons for this behaviour will be explained and the border of the fatigue limit of high strength steels will be discussed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call