API 5L pipe tolerances mainly include outer diameter tolerance, wall thickness tolerance, out-of-roundness tolerance, and curvature.
Outer diameter tolerance
The outer diameter tolerance of API 5L pipes varies according to the diameter of the pipe:
For pipes with an outer diameter less than 60.3mm, the tolerance is -0.8mm to +0.4mm.
For pipes with an outer diameter between 60.3mm and 168.3mm, the tolerance is ±0.020X outer diameter.
For pipes with an outer diameter between 168.3mm and 610mm, the tolerance is ±0.0075X outer diameter, but the maximum value is ±3.2mm.
For pipes with an outer diameter greater than 610mm, the tolerance is ±0.01X outer diameter, and the maximum value is ±4.0mm.
Wall thickness tolerance
The wall thickness tolerance of API 5L pipes is specified as follows:
The allowable deviation of wall thickness is that the minimum wall thickness at any point is less than the specified nominal wall thickness by no more than 12.5%.
Out-of-roundness tolerance
The out-of-roundness tolerance varies according to the diameter and wall thickness of the pipe:
For pipes with OD/Wall thickness ≤ 75, the out-of-roundness tolerance is 0.015X OD, but the maximum value is 15mm.
For pipes with OD/Wall thickness > 75, the out-of-roundness tolerance is determined by agreement.
Curvature
The curvature requirements of API 5L pipes are as follows:
The curvature of the steel pipe should not be greater than 1.5% of the total length of the steel pipe.
The tolerances for random length pipe shall be as below table (API SPEC 5L Table 12).
|
Random length designation m (ft) |
Minimum length m (ft) |
Minimum average length for each order item m(ft) |
Maximum length m(ft) |
|
Threaded-and-coupled pipe |
|||
|
6 (20) |
4.88 (16.0) |
5.33 (17.5) |
6.86 (22.5) |
|
9 (30) |
4.11 (13.5) |
8.00 (26.2) |
10.29 (33.8) |
|
12 (40) |
6.71 (22.0) |
10.67 (35.0) |
13.72 (45.0) |
|
Plain-end pipe |
|||
|
6 (20) |
2.74 (9.0) |
5.33 (17.5) |
6.86 (22.5) |
|
9 (30) |
4.11 (13.5) |
8.00 (26.2) |
10.29 (33.8) |
|
12 (40) |
4.27 (14.0) |
10.67 (35.0) |
13.72 (45.0) |
|
15 (50) |
5.33 (17.5) |
13.35 (43.8) |
16.76 (55.0) |
|
18 (60) |
6.40 (21.0) |
16.00 (52.5) |
19.81 (65.0) |
|
24 (80) |
8.53 (28.0) |
21.34 (70.0) |
25.91 (85.0) |
API 5L PSL2 X56 Steel Pipe
