STRAIN-HARDENING BEHAVIOR AND ITS RELATIONSHIP TO TENSILE MECHANICAL-PROPERTIES OF DUAL PHASE STEEL

Using the modified Crussard-Jaoul analysis, the strain hardening behaviour of a predeformed 1020 dual phase steel with quenching and quenching plus tempering treatments was examined, showing that this dual phase steel deforms in two stages. The relationships between the maximum uniform strain epsilon(u), the stress ratio (true initial stress sigma(o)/true maximum stress sigma(u)) and the strain hardening exponents in the first stage and the second stage (m1 and m2) were derived based on the Swift equation and the Considere instability criterion, which showed good agreement with the experimental results for the present 1020 dual phase steeL The dependence of strength sigma(u) and ductility epsilon(u) of dual phase steel on the exponents m1 and m2 was discussed using the two derived relationships.