HOT DEFORMATION AND PROCESSING MAPS OF ROTOR STEELS

Abstract

For the major engineering components and its application, the usage and importance of steels play a major role and leading over other materials. For the many critical strategic application such as nuclear and thermal power plants, automobiles, ship buildings, military applications the demand of high performance alloyed steels is increased. For the production of low cost quality products like low weight high strength, better heat resistant, higher toughness material the desire processing parameters for manufacturing is needed. Heat treatment and alloy design in steel for the manufacturing engineering components play a major role to enhance the mechanical, corrosion and thermal property which promote to withstand in highly stressed environmental conditions. The thermomechanical processing technique is related to the hot working of materials, which improve the property of the materials and also control the hot deformation processing parameters like strain rates temperature, strain, reheating temperature to achieve desire microstructural and mechanical property of the materials. Report of the literature studies shows a broad range of hot deformation behavior characteristics and comparative study for the different grades of rotor steels in a single platform is required for better understanding. Different types of processing maps and Poletti instability criteria need to be introduced with microstructural correlation to decide desire processing parameters. A review of literature also exhibits the hot deformation study needs to imply an Artificial neural network (ANN) for the precise result of deformation to analyze for hot deformation characteristics and modeling studies. Chapter four consists of some necessary theory and analysis which helps for the fulfillment of aim of the study. Constitutive equation analysis and various processing maps related to a different model with different criteria have been discussed. In this section kinetics of dynamic recrystallization based on Avrami type equation has been explained as well as calculations of ANN modeling is discussed in this chapter.