Influence of structure factors on the hardening of stable and metastable austenitic-martensitic steel in the linear and plane stressed state

Abstract

1. For the investigated austenites and austenitic-martensitic steels is it shown that an increase in strain and phase hardening (caused, respectively, by the transition from the linear to the plane stressed state and by the increase in the volume content of the hardening phase) is revealed in activation of the processes of grain refinement and of an increase in the dislocation density in the austenite. 2. A peculiarity of the substructure of the two-phase steel with stable austenite is relaxation of the effects of phase hardening in plastic deformation. 3. Under conditions of development of the γ→α transformation the more stressed substructure of the austenite is inherited by the deformation martensite, which leads to an increase in its strength. As the result of this there is an increase in the level of flow stresses of the austenitic steel in biaxial tension and a decrease in the sensitivity of the tensile strength of the austenitic-martensitic steel to the quantity of residual austenite. The latter is responsible for the independence of the tensile strength of the metastable austenitic-martensitic steel from the quantitative relationship of the phases.