On Creep Rupture Characteristics in STS304 Stainless Steels

In this study, the creep rupture tests of STS304 stainless steels were investigated at three different elevated temperatures of 600 degrees C, 650 degrees C and 700 degrees C under the constant creep stresses. Creep rupture characteristics Such as creep stress, creep rupture time. steady state creep rate and so on were evaluated. The behaviors of creep rate curve and initial strain are compared at three different elevated temperatures. The stress exponent (n) at 600 degrees C, 650 degrees C and 700 degrees C based oil steady state creep rate showed 22.5, 20.6 and 11.4 respectively. By increasing the temperature, the stress exponent is decreased. At the temperature of 700 degrees C, the lowest stress exponents are shown and this behavior is also observed in the case of stress exponent based oil rupture time. The creep life prediction by LMP method is presented and the equation of this result is as follows: T(logtr+20)=-0.00515 sigma(2)-14.56 sigma+24 126.