Paper Title
Effect of Test Temperature on Stress Triaxility Behavior of Modified 9CR-1MO Steel

Abstract
In the present investigation, elastic-plastic axisymmetric finite element analysis has been performed to simulate tensile behavior of Modified 9Cr-1Mo steel. The modified 9Cr-1Mo steel is subjected to double austenitization treatment (a two stage normalizing at 1150 ºC/2h/air cooling+1050 ºC/2h/air cooling) followed by tempering at 750 ºC for 2h in order to refine microstructure and improve precipitation state.Tensile tests are conducted at -196 ºC, 20 ºC and 200 ºC to analyze the effect of test temperature on stress triaxility. High fracture stress generated in the perpendicular direction during necking. Stress triaxilaity is increased as necking is deppened. A typical type of rosette fracture with axial splitting is noticed, which is dominant at -196 ºC. Keywords - Modified 9Cr-1Mo Steel, Stress Triaxiality, Austenitization Treatment