Estimating the working life of steel beams on the basis of their mechanical properties

Abstract

Forged steel 50 rollers are used in the roughing group of wire and small-rod mills. In intense rolling, the roller pin often breaks, since the pin experiences the maximum stress. It is established that the fracture is of fatigue type, and three disintegration zones are identified. Crack propagation is due to the stress in the crack tip. The rate of crack propagation in cyclic loading depends on the structure of the metal, the grain size, and the mechanical properties of the rollers. The unbroken rollers are characterized by high values of the impact strength, initial and final temperatures of ingot forging, and σy/σB. An empirical dependence of the number of roller rotations to pin fracture on the mechanical properties of the material and the loads is established. Small-grain structure of the metal matrix and purity of the metal ensure a good combination of strength and plasticity.