Review on the Fatigue Mechanisms in Automotive Valve Springs 2011-36-0003

This paper presents a review on the fatigue mechanisms in automotive valve springs manufactured on high-strength steel, as well as in other similar parts, like as helical suspension spring. The review was conducted with a phenomenological focus to support new developments in material for use in Otto and Diesel engines. Mechanical fatigue is a common process of damage that occurs in components subjected to cyclic loads, but in the particular case of valve springs, this problem is controlled through the project restriction, usually with the limitation of higher levels prescription of shear stress. In an attempt to increase this limit, allowing greater efforts at the elastic region the Material Engineering designs materials with higher toughness and the Manufacturing Engineering plays in the prevention or defects minimization, often inherent to the material. Considering this scenario, the proposal of austempered valve springs instead of the traditional quenched and tempered might assist in this challenge. Thus, this review presents a brief discussion about this theme, with the goal of supporting a search in progress using the austempered valve spring.