Effect of strain and strain rate on the bauschinger effect response of three different steels

摘要

The Bauschinger behavior after a strain reversal was evaluated for samples with microstructures representative of production sheets for a low-carbon (LC) steel, a high-strength low-alloy (HSLA) steel, and a dual-phase (DP) steel. The microstructures were produced in the samples by laboratory hot rolling and heat treatment. Bauschinger tests were run at strain rates of 0.0001, 0.001, and 0.01 s−1, with tensile prestrains between 1 and 7 pct. After the reversal, the samples were strained 2 pct in compression. The Bauschinger effect is described by a Bauschinger effect parameter (BE), which is the difference between the steel strength at reversal and the 0.05 pct offset yield strength on the reversal, normalized by the steel strength at reversal. It is found that the Bauschinger effect is a continuous increasing function of the strength of the steel, provided the steel is prestrained at least 2.5 pct or beyond the yield point elongation. A single trend line describes the Bauschinger effect variation with steel strength, for all three steels in the present study and for an aluminum-killed drawing quality (AKDQ) steel from a previous investigation. No strain rate influence on the BE was found, due to the limited strain rate range and data uncertainty.