PSI - Issue 42

S. Lindqvist et al. / Procedia Structural Integrity 42 (2022) 42–49 Author name / Structural Integrity Procedia 00 (2019) 000– 00

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25  C, 512  a 0.645 100  C, 448  a 0.627 200  C, 383  a 0.513 300  C, 612  a 0.519 300  C 25  C

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J-R curves at 25  C, normalization method

Average J-R curve at 25  C compliance method Basic method

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Figure 2. a) The J-R curves at 25 ° C, 100 ° C, 200, 300 ° C, b) comparison of the different methods for determining the J-R curve.

3.1. Cooling rate Figure 3 shows cooling rates at different depth locations for the calibration specimen. The cooling rate was measured at the surface, 4, 8 and 12.5 mm from the surface. The cooling rate is slowest at the center of the specimen (depth 12.5 mm). The cooling rate at the center is 2 ° C/s. The difference in the cooling rate at 8 mm is comparable to the cooling rate at the center. The biggest difference in the cooling rate is observed between the surface and at 4 mm. The cooling rate at the surface is fastest. Additionally, the cooling rate is faster when cooling from 300 to 100 ° C than from 100 ° C to room temperature.

Surface Depth: 4 mm Depth: 8 mm Depth: 12.5 mm Surface Depth: 4 mm Depth: 8 mm Depth: 12.5 mm

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Figure 3. a) Cooling rate at various depths. b) The cooling rate during calibration conforms to the cooling rate obtained during testing. The cooling rates were parametrized from data between 300 ° C and 100 ° C.

Table 1 shows the cooling rates measured during fracture toughness testing. The average cooling rate is 1.9 ° C/s. During calibration the average cooling rate is 2.7 ° C/s at 8 mm and 2.0 ° C/s at the center. During testing, the specimens can heat up due to the work done, which can affect the cooling rate. Table 1 shows also the J-integral value before the cooling starts, the final temperature and the total crack growth.