1. No cracks, folds, folds, peels, scabs and scales are allowed on the inner and outer surfaces of the steel pipe. These defects should be completely removed. The grinding of the surface defects should be smooth and smooth. The depth of the clearance shall not exceed the negative deviation of the nominal wall thickness. The actual thickness of the defect removal zone shall not be less than the minimum allowable wall thickness of the steel pipe. The method of welding shall not be used.
2. The straight path appearing on the inner and outer surfaces of the steel pipe must be ground. The depth of clearance must not exceed the negative deviation of the nominal wall thickness. The actual thickness of the defect removal area should not be less than the minimum wall thickness allowed by the steel pipe.
3. End shape: Both ends of the steel tube should be cut at right angles and the burrs removed.
4. Solder joint interface is not allowed on the pipeline.
Size tolerance of API 5L X52 seamless pipes
1. Diameter and ovality
Diameter deviation: ± 0.01D, and the maximum does not exceed ± 4mm;
Ellipticity deviation: 0.02D, and maximum 10mm.
2. Wall thickness deviation
Wall thickness deviation of steel pipe: -5% to +20%, but the average wall thickness of each pipe shall not be lower than the specified pipe wall thickness.
3. Steel pipe straightness deviation
a. The total deviation of the total length of the steel pipe relative to the straight line shall be ≤ 0.2% of the length of the steel pipe;
b. The local deviation from the straight line should be ≤ 4mm in the length of each pipe segment of 1000mm.