Fatigue properties of the HSLA steel in high and ultra - high cycle region

This work presents a study of the fatigue properties in the example of Swedish steel Hardox 400. Fatigue tests were carried out in the area of high and ultra - high cycle region. From the practical point of view the dur ability of some components in the automotive industry and similar technical applications such as special semitrailers ranges between 10 8 and 10 10 cycles. But, only a few experimental results b e- yond 10 7 cycles are available now. The main objective of this r esearch was to provide independent results to the company which uses Hardox steel in the construction of semitrailers. Selected mechanical and fatigue tests were carried out with the aim to study fatigue proper ties of Hardox steel. Based on the obtained ex perimental results the fatigue properties of this still not well recognized type of steel are discussed .