Improved methodology for determining tensile elastic and plastic strain components of alloy 617

Abstract

This paper presents an improved methodology for calculating tensile elastic and plastic strain components in total creep strain, which are needed in the generation of the isochronous stress-strain curves (ISSC). The procedures for the RCC-MR code and Blackburn’s methods to determine the total strain are analyzed in detail, and a new method is proposed to determine the tensile elastic and plastic strain components. To practically obtain the tensile elastic and plastic strain components for Alloy 617, high-temperature tensile tests were conducted at 800, 850, 900, and 950°C. Using the tested data, three methods of the RCC-MR code, Blackburn, and the newly proposed method were applied and compared. In the elastic regime, the three methods were identical in the tensile curves, but in the plastic regime, Blackburn’s method was higher in the stress-strain curves than the RCC-MR code. The difference gap for the two methods was larger with an increase in the plastic strain. In addition, the proposed new method revealed almost midway values for the two methods. It was suggested that the proposed method is useful to determine tensile and plastic strain components.