PSI - Issue 17

Jan Klusák et al. / Procedia Structural Integrity 17 (2019) 576–581 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

3

578

Rolling direction

A

B

Fig. 1: Orientation of specimens with respect to the rolling direction

Fig. 2: Geometry of specimens for VHCF tests

3. Experimental results

The four sets of specimens were tested to gain fatigue life curves. Only high frequency (20 kHz) tests were performed. Both grades of steels and both directions A and B exhibited very high cycle fatigue behaviour. Failure after 1  10 7 cycles occurred in case of all studied sets. Results are presented here in the form of S-N diagram where comparison of all sets of samples is shown in the Fig. 3. Particular grades of steel and directions are distinguished by colour and shape of the marks. Specimens able to bear particular loading 1  10 10 cycles were considered as run outs. The run outs are marked by the blank points. Note that one specimen of the steel S355 J0A and two specimens of S355 J0B exhibited failure after 1  10 10 cycles.