RESEARCH OF STRESS-STRAIN STATE OF THE REINFORCEMENT PROFILEDURING THE STRETCHING‒BENDING‒REBENDING (COLD STRETCHING)

Abstract

The Cold Stretching method (SBR: stretching, bending with rebending), widely used abroad, makes it possible to implement low strain degrees in high-performance reinforcement production lines, increasing the level of reinforcement mechanical proprieties till A500. The process consists of a combination of stretching the reinforcement at a controlled degree of cold plastic deformation with the addition of alternating bending elements in special roller systems. The paper presents the results of computer finite element modeling in SIMULIA Abaqus complex of stress-strain state of
periodic profile reinforcement in the process of SBR. The simulation results showed that during the SBR process the reinforcement receives an equivalent degree of compressive and tensile strain when passing through each subsequent roller, that is, during the transition between groups of rollers and individual rollers in a pair, each section of the profile receives a tensile load commensurate in modulus with the subsequent compression load. To verify this observation in the industrial conditions of OJSC MMK-Metiz, samples of the studied A400 reinforcement were selected in the hot-rolled state and after the SBR process. The study showed that the geometric parameters of the profile remained within normalized limits and no protrusion integrity violations were observed, which confirms the modeling results.