Damage detection and casting defect statistics of typical four branch cast steel joints

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As shown in Figure 1, because the shape of casting defects in the node is irregular, the maximum value of each dimension in the irregular shape is selected as the evaluation index of casting defect size. See the table for damage detection results of typical four branch cast steel joints, and see Fig. 2 ~ Fig. 7 for typical casting defects on the section of cast steel joints. This section will count the casting defects of each section, including their types, positions and sizes, and make a specific analysis of the casting defects at key positions, mainly analyzing the randomness of the distribution of casting defects in spatial positions.

(1) A serious layered casting defect was found on the section B of the main pipe. The casting defect was close to the top of the cast steel joint, with a circumferential length of about 30mm, and there were a large number of black inclusions between the two layers. (Figure 2)

(2) There is shrinkage defect on the section C of the main pipe. The casting defect is located at the junction of the main pipe and the branch pipe, which is the blind area of flaw detection. (Figure 3)

(3) The inclusion defect appeared on the F section of the main pipe. After cutting the A-A section with a water knife, it was found that the inclusion diameter here reached 20mm. (Figure 4)

(4) Continuous dense porosity defects with different sizes were found on the G section of the main pipe, which was close to the top of the cast steel joint and located at the riser. At the same time, shrinkage and looseness defects occur in the intersection area between the stiffener and the cast steel main pipe, which is in a long strip along the edge of the stiffener and on one side of the main pipe. (Figure 5)

(4) The H section of the branch pipe shows the casting defects at the intersection of the branch pipes. The main casting defects are shrinkage defects, which extend longitudinally along the branch pipe, with a length of about 30mm. This is the blind area of ultrasonic flaw detection. (Figure 6)

(5) The section B of the branch pipe shows that there are many small shrinkage defects in the section, and the shrinkage hole diameter is 0.3 ~ 0.8mm, which is located in the middle of the branch pipe. (Figure 7)

Section numberTotal number of casting defectsInclusion defectShrinkage defectStomatal defectShrinkage defectDelamination defectMaximum size of casting defect / mm
A4121//2
B8241/131
C16654/132
D201163//20.5
E234910//13.5
F11425//7.2
G11425//16
H25/1510//41.5
I10325//10.5
J311282//11
K16196//2.5
L6/41/112
M0//////
N64/2//8
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