Austenitic-grain-size-dependent constitutive model of deformation behavior of TRIP steel
Iwamoto Takeshi; Tsuta Toshio
Abstract:Due to the strain-induced martensitic transformation during plastic deformation, a transformation-induced plasticity (TRIP) phenomenon is generated. With the TRIP phenomenon, the TRIP steel possesses favorable mechanical properties such as high strength, ductility and toughness, and is frequently employed as a structural material. In the past study, it was clarified that the deformation behavior of TRIP steel depends upon the austenitic grain size. In order to obtain the expected mechanical properties of TRIP steel, prediction and control of the material characteristics in the deformation processes is essential. Here, the strain-induced martensitic transformation kinetics and the constitutive equation of TRIP steels which the dependence of the austenitic grain size can be described are proposed. Then, the deformation behavior of a type 304 austenitic stainless steel cylinder is simulated under the different environmental temperature with the various austenitic grain sizes by the finite-element method. The possibility of the improvement of the ductility through control of the austenitic grain size is discussed. Key Words:TRIP steel, constitutive equation, strain-induced martensitic transformation kinetics, austenitic grain size, mechanical properties