Study on Bauschinger Effect in X80 Steel under Axial Loading and Bending

Abstract

The Bauschinger effect (BE) of X80 Pipeline Steel was tested through axial tension and compression loading. Forward and reverse axial loading schemes were performed to investigate the influence of deformation history on the mechanical character. The curves of forward and reverse stress-strain were both recorded. The results show that the yield strength decreases as the pre-plastic strain increases. On the basis of the experimental data, an empirical formula was derived regarding the decrement of the yield strength as a function of the pre-plastic strain. Additionally, further investigations on the BE of X80 steel were conducted by bending tests. The bending moment-strain curves were all recorded for both first and reverse loading. It shows that the yield moment also decreases as the pre-plastic strain increases. Based on the theory of elastic-plastic mechanics, the formula of yield moment decrement as the pre-plastic strain increase was obtained. The results show that the experimental tests are in good agreement with the formula prediction.