INFLUENCE OF WEDGE ROLLING ON THE HIGH-CYCLE FATIGUE

Rolled billets of product “shaft” made of steel Cò35 (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). The inspection was conducted using plate samples with dimensions 50*10*2.1 mm:

- 5 samples (No 1) were cut from an area that underwent deformation during rolling

- 5 samples (No 2) were cut from an area that was not deformed during rolling.

The inspection was conducted according to the method of symmetrical lateral bending of a console fastened plate sample. Deformation amplitude corresponded to the tension level of 500 MPa

As a result of the inspection performed it was established that:

1. Cyclic durability of steel Ñò35 samples under tension amplitude sa =490-545 MPa is 1,6-3,0 * 104 tension cycles till destruction and it grows with the steel hardness level increase

2. In the sphere of low-cycle fatigue steel Ñò35 samples show an increase in the average value of the number of cycles till destruction by >=3% as compared to the initial state

Figure 1. Sample extraction scheme for cyclic durability inspection

1 - deformed sample
2 - sample that did not undergo deformation