PSI - Issue 60

Ganesh Nigudage et al. / Procedia Structural Integrity 60 (2024) 678–689 Ganesh Nigudage /Structural Integrity Procedia 00 (2023) 000 – 000

684

3.1.3. Characteristic displacement parameters used to correlate with total elongation If specimen exhibits load drop after reaching the peak load (F m ) then the displacement corresponding to 20% force decrease with respect to F m is defined as v f (displacement at end of test). If the specimen exhibits sudden force drops caused by unstable crack propagation followed by crack arrests then v f is replaced by v 1p i.e. displacement corresponding to first significant pop-in (Enrico Lucon et al., 2020). The displacement at maximum force (v m ) and v f , shown in Fig.6, are used to correlate with total elongation.

Fig.6. Characteristic small punch displacement that are used for correlating with total elongation

4. Derivation of empirical correlation constants Empirical correlations between SP characteristic values and uniaxial tensile properties were derived using archive base room temperature test data, archive base data of test at - 60℃ and archive weld room temperature test data. In SPT, two specimens were tested for each type material and test temperature. The characteristic values of force, punch displacement are provided in Table 2.

Table 2. Results of Small punch test for Cr-Mo-V RPV steel in different material condition

Specimen thickness

Specimen ID (test temperature) Archive Base (25 o C) Archive Base (25 o C) Archive Base (-60 o C) Archive Base (-60 o C) Archive weld (25 o C) Archive weld (25 o C)

Fe proj

Fe int

F h0/10

F 0.1mm

F m

F 0.48mm

F 0.65mm

v m

v f

(h o )

(N)

(N)

(N)

(N)

(N)

(N)

(N)

(mm)

(mm)

0.5

350.4

376.4

461.3

551.9

1709

707.1

864.7

1.82

2.13

0.5

365.7

391.4

470.88

545.01

1711.7

693.5

851.2

1.87

2.18

0.51

486.2

515.8

616.94

704

2173.4

812.5

976.5

1.9

2.18

0.5

462.7

489.3

585.47

665.33

2070.2

769.2

940.5

1.87

2.36

0.5

283.7

299

373

440

1537.8

578.2

709

1.91

2.14

0.5

289.3

307.8

369.67

425.8

1538

541.5

666.7

1.96

2.08