Fatigue Analysis of a Cross Wedge Rolled Rail Axle
摘要
The article presents and elaborates on the issue of fatigue cracking of forged railway axles formed using the cross-wedge rolling method. Fatigue tests were conducted using the rotary bending method, with the subject of the study being a railway axle made of C35 steel, formed at a temperature of 1180 °C at a scale of 1:5. The axles obtained through cross-wedge rolling were subjected to an annealing process before samples were taken for fatigue testing. Subsequently, the obtained fractures underwent fractographic analysis to identify morphological characteristics of the cracks and evaluate crack propagation mechanisms. Two fractures were examined using a Nikon SMZ stereoscopic microscope and a Phenom Pro X scanning microscope. In the crack initiation zone, grooves emanating from the initiation point and dark carbonaceous areas were observed. In the transitional zone, a dense network of cracks was found, while in the fracture zone, spherical indentations, pores, and signs of significant plastic deformation were detected. Fatigue strength tests conducted using the rotary bending method confirmed the high durability of railway axles produced using the cross-wedge rolling technology. Fatigue strength tests conducted using the torsional bending method confirmed the high material strength of railway axles produced by this technology. Such results are in line with safety and strength standards, which is a significant aspect of ensuring safety in railway transportation.