PSI - Issue 3

M.A. Beltrán et al. / Procedia Structural Integrity 3 (2017) 57–67

64

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Author name / Structural Integrity Procedia 00 (2017) 000–000

Fig. 8. Tensile stress properties in the L and C directions of API-5L X46 steel.

Table 4. Tensile mechanical properties of API-5L X46 steel.

Direction

Ys (MPa)

UTS (MPa)

Elongation %

API-5L X46 Steel

L C

339 424

504 530

35.5 31.6

Literature API-5L Steel properties

X46 X52

Min-317 Min-360

Min-434 Min-460

- -

3.6 Charpy impact properties Charpy impact tests results, of all the specimens in the longitudinal and circumferential orientations, are shown in Table 5. The CVN energy in the L direction is lower than the C direction. According to the CVN results, the fracture toughness values (K IC-CV ) were calculated in order to estimate the fracture resistance difference between the L and C directions. It could be seen both a difference larger than 13% in CVN energy and K IC-CV . Table 5. CVN energy and K IC cv results in the L and C crack propagation directions within the API-5L X46 steel. Direction CVN energy (J) K IC cv (MPa√m) C 340 301 L 300 254 3.7 CVN fracture surfaces The fracture surfaces of the CVN specimens oriented in the L and C directions are shown in the Fig 9. A larger amount of plastic deformation associated to the fracture in the CVN specimen oriented in the C direction than the L oriented specimen is observed. The area reduction percent was measured in the central region of the fracture surface, in order to stablish the amount of plastic deformation associated to the fracture, results are shown in Table 6.

Table 6. Reduction area percent (%RA) of the CVN specimens oriented in the L and C directions within the API-5L X46 steel.

RA (mm)

Direction

% RA (%)

L C

6.86 5.91

31.2 41.0