API 5L Gr B Inspection-Flattening Test Sample Requirements:
The steel pipe samples for the flattening test shall be cut from the steel pipes that have passed the appearance inspection. The length of the steel pipe test sample shall not be less than 10mm, but not more than 10mm. The edges of the steel pipe test sample are allowed to be rounded or chamfered by filing or other methods. If the test is conducted on the end of a full-length pipe, the depth of the cut shall be at least 80% of the outer diameter perpendicular to the longitudinal axis of the pipe at a distance of the sample length from the end face of the pipe. When cutting the sample, it shall be prevented from damaging the sample surface and changing the properties of the steel pipe due to heating or cold working.
Operation Procedure：
Place the sample between two parallel pressing plates. The weld of the welded pipe shall be placed in the position specified in the relevant product standards. Use a press or testing machine to apply force in the radial direction, press uniformly to the flattening distance H at a speed not greater than 50mm/min, remove the load, remove the sample, and observe the bending part of the sample with the naked eye.
Test Results：
The evaluation of the flattening test results shall be based on the requirements of the relevant product standards. When there is no regulation in the product standard, if there is no visible crack without using a magnifying glass, it should be evaluated as qualified. Minor cracks only at the edges and corners of the specimen should not be rejected.
API 5L GR.B psl2 sour pipelines
