PSI - Issue 33

J.L. González-Velázquez et al. / Procedia Structural Integrity 33 (2021) 221–228 J.L. González-Velázquez et al. / Structural Integrity Procedia 00 (2021) 000–000

226

6

Table 2 shows the dimensions of the zones of non-metallic inclusions detected by the non-destructive inspection in the pressure vessel.

Table 2. Dimensions of the zone of inclusions detected in the pressure vessel (all dimensions in inches). Defect ID Wall thickness away of lamination ( t rd ) Longitudinal dimension (s) Circumferential. dimension (c) Minimum measured thickness ( t mm ) Lamination height ( L h )

Lamination to lamination spacing ( L s )

Spacing to a nearest major discontinuity ( L msd )

Spacing to nearest weld joint ( L w )

ENV-3.2 ENV-2.4 TP-1.6 TP-2.23 TP-2.24

1.046 1.014 1.098 1.112 1.112

16.00 13.00

14.00 10.00

0.296 0.582 0.296 0.287 0.278

0.630 0.242 0.720 0.552 0.616

40 40

35.83 13.78 16.50

0.5

14.0 30.0 34.0 17.5

7.50

6.50

22.5 16.5 16.5

14.00 12.50

16.50 22.00

3.00 6.00

ENV-3.2

ENV-3.2

ENV-3.2

TP-1.6

TP-1.6

Fig.5. Photographic records of zones of non-metallic inclusions detected by PAUT in the pressure vessel.

4. FFS assessment of inclusion zones by Part 13 of API 579 Table 3 presents the results of Part 13 of API 579 Level 1 and Level 2 assessments of the zone of inclusions listed in Table 2, regarding them as laminations, and evaluated according to the procedure described in section 2.2 of this paper. The step sequence was modified to display the calculations in a logical order. The Level 2 assessment was done by a commercial fracture mechanics application software assuming that the defect is a buried crack, whose dimensions were 2 a = L h , 2 c = max [ s , c ], the ligament length d = t mm , and the thickness was t rd , as listed in Table 2. The mechanical properties of the SA 516 Gr.70 steel were taken as the nominal values YS = 38 ksi and UTS = 70 ksi and assuming a K IC = 100 ksi √ . The reference stresses were inferred from the internal pressure. TP-2.23