13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- 2. Experimental Procedures 2.1. Material and Specimen The material used is P92 steel. The chemical composition of P92 steel is shown in Table 1. The specimen used is a C(T) specimen with side-grooves of 25% of specimen thickness. The geometry and size of the C(T) specimen is shown in Fig. 1. Table 1. Chemical composition of P92 steel in wt.% Figure 1. The geometry and size of a C(T) specimen (Unit: mm) 2.2. CCG Tests Procedures and Experimental Conditions The interrupted CCG tests were conducted by lever-arm high temperature creep testing machine (Type RT-30) manufactured by TOSHIN KOGYO. The creep crack length was measured by direct current potential drop (DCPD) method [11, 12]. Load line displacement (LLD) was measured by displacement sensing bars and linear gauges. A schematic illustration of measurement methods of creep crack length and LLD is shown in Fig. 2. The interrupted CCG tests were carried out under the conditions of 600 °C and initial stress intensity factor Kin = 42 MPam1/2. These tests were interrupted at different times, as shown in Table 2. Figure 2. Measurement methods of creep crack length and LLD Table 2. Experimental conditions of interrupted CCG tests
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