PSI - Issue 14

K.C. Sahoo et.al./ Structural Integrity Procedia 00 (2018) 000 – 000

K.C. Sahoo et al. / Procedia Structural Integrity 14 (2019) 60–67

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The variations of creep rate ( ) with time period has been shown in Fig. 4(a)-(c). The creep rate decreased with time period, attained a steady state creep rate and started accelerating up to the final failure of the specimen. The duration of transient stage is very small compared to steady state and tertiary stage.

Fig.4 Variation of creep rate with rupture life of the steel at 923 K, 973 K and 1023 K.

Fig.5 shows the variation of steady state creep rate with applied stress at all those temperatures. It consists of decreasing creep rate, saturation stage and acceleration up to final failure. The variation of steady state creep rate with applied stress obeys Norton’s power law ( ) with n values decreases with increase in temperature.

Fig.5 Variation of steady state creep rate with applied stress