Evaluation of tension-compression asymmetry of a low-carbon steel sheet using a modified classical compression test method

Abstract

A modified classical compression test method was used to examine in-plane tension-compression asymmetry in a low carbon steel sheet. In this compression test method, interfacial friction between the compression platens and specimen surfaces was significantly reduced by use of polycrystalline diamond plates installed on the compression dies. Furthermore, crosshead displacement of the universal testing machine, which inherently includes deflection of the machine itself, was corrected to the net deformation of the specimen based on a series spring model. Consequently, precision of the compressive strains obtained with the present test method is equivalent to that attained in the standard tension tests using wire strain gauges. For tension and compression tests performed at in-plane directions of 0°, 45° and 90° relative to the rolling direction (RD), significant tension-compression asymmetry (i.e. strength differential effect (SDE)) was observed. In all the mechanical tests in the three testing directions, flow stresses in tension tests were smaller than those in compression tests.