A SHAFT part made of Russian steel grade Ñò35 was used for testing. (Chemical composition C=0,32-0,4; Si=0,17-0,37; Mn=0,50-0,80; Si<=0,04; P<=0,035; Cr<=0,25; Ni<=0,30; As<=0,08; N<=0,008; Cu<=0,30).

Samples in the form of a plate with dimensions 50*10*2,1mm were used for testing. (see drawing)

- 5 samples (Nr.1) were taken from a section that had had no plastic deformation during wedge rolling

-· 5 samples (Nr.2) were taken from a section that had had plastic deformation during wedge rolling.

The samples were fastened at cantilevers and were tested by symmetric bend method. The deformation amplitude was equal to a force of 500MPa. Test results are the following:

1. Cyclic durability of samples under force sà =490-545 MPa is equal to 1.6¸3.0 * 104 exertion cycles. Cyclic durability increases by testing harder steels

2. In the area of low-cycle metal fatigue, a medium number of cycles increases by ³3%

Drawing 1: Sample Selection for testing on high-cycle bending:

1 - strainless sample
2 - strained sample