The effect of structure and properties of steel 30KhGSA on the shaping of round blanks using plastic bending

Abstract

The influence of the structure and properties of 30KhGSA steel on the shaping of round-shaped blanks using the method of plastic bending is studied. Bending of the initial steel rod sample results in the sample fracture. Methods of mechanical tests and metallographic analysis used in the study showed that the steel sample in the initial satate has a structure of lamellar perlite. A comparative evaluation of the structure and properties of the steel samples prior to and after additional heat treatment (spheroidizing annealing) revealed that annealing enhanced the plastic properties of the sample and changed the sample structure from lamellar to globular perlite. Formation of the granular perlite structure indicates to the devision of the plates into smaller particles and their further spheroidization due to transferring carbon through the surrounding solid solution. Thus, additional cyclic heat treatment of steel in the state of delivery, allowed us to solve the problem of the rod fracture upon subsequent plastic bending. As a result of the research, the values of the mechanical properties of steel were obtained experimentally, which ensure the process of bending the rod into a round shaped blank without destroying it. The proposed mode of cyclic heat treatment (spheroidizing annealing) can be used to improve the plasticity characteristics of the metal upon shaping by the method of plastic bending.