Strain path's influence on the elastic behaviour of theTRIP 700 steel

Abstract

This paper deals with the analysis of thestrain path's influence on the elastic behaviour of TRIP700 steel; it aims to validate the cyclic testing method to characterise inelastic behaviour of advanced high strength steels (AHSS). Different cyclic tests are done, where the strain path is changed from test to test. Large deformation strain gages are used to determine the inelastic behaviour of the specimens at macro-level. At a lower scale, stress measurements are carried out using the XRD technique during an in-situ tensile test: ferrite and austenite phases’stresses are measured before unloading and after loading again to study the strain path's influence. By means of this work it is confirmed that the elastic strain path has no influence on the unloading–loading of this TRIP steel. These results prove that conventional loading–unloading cyclic testing is a valid methodology for a detailed characterisation of the elastic modulus and reliable numerical modelling of springback.