PSI - Issue 60

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Chitresh Chandra et al. / Procedia Structural Integrity 60 (2024) 165–176 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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growth behaviour has been explained and correlated with various fracture mechanics parameters such as ΔK , and (C t ) avg . 2. Experimental Details

Fig. 1: Geometry of specimen adopted in creep-fatigue crack growth test

Fig. 2: Microstructure of P91 steel using (a) optical and (b) Scanning Electron Microscope

The P91 steel procured for the CFCG test was normalized at 1100 °C for 1 h and then tempered at 760 °C for 1 h prior to being received. Table 1 displays the P91 steel's elemental constitution. As shown in Fig. 1, C(T) specimens of P91 steel having dimensions of 50 mm in width, 20 mm in thickness, and 20 mm in starting notch were made in accordance with the ASTM E-2760 standard and pre-cracked for 2.5 mm in a servo-hydraulic Universal testing Machine (UTM) (Make: BISS; Model: UT040100). Precautions have been taken to ensure that the pre-cracking load is less compared to the test load. After that, side grooves with a 45° angle and a 2 mm depth were machined onto both sides of the specimen in line with the v-notch, right next to the sample's pre-cracked crack line. The side-grooved samples were then put through CFCG tests in servo-electric UTMs (Zwick Roell; Kappa 100SS) at 600 ºC with two