What are the procedures for inspecting plastic-coated steel pipes

The main inspection methods for plastic-coated steel pipes include appearance inspection, thickness measurement, pinhole test, bending test, flattening test, low temperature test, etc. Each inspection method has its own focus.

1. Appearance inspection is to inspect the appearance quality of coated steel pipes with the naked eye.

2. Thickness measurement: On the two cross-sections of the plastic-coated steel pipe, use a thickness gauge to measure the coating thickness at any four orthogonal points on the circumference to ensure that the coating thickness meets the regulations.

3. Pinhole test: Use an electric spark leak detector to inspect the steel pipe coating under the specified test voltage, and observe whether there is spark generation to determine whether the insulation performance of the coating is good.

4. Bending test: Bend on a bending machine or mold to observe whether the coating peels off, cracks, etc. It should be noted that during the bending test, there is no filler in the pipe, and the weld is located on the side of the main bending surface.

5. Flattening test: Place the specimen between two flat plates and gradually compress it on the pressure testing machine until the distance between the two flat plates is four-fifths of the outer diameter of the specimen. When flattened, the weld of the coated steel pipe is perpendicular to the load. direction, check whether the coating is peeling off, cracking, etc.

6. Low-temperature test: Place the test piece in a low-temperature box, stay there for one hour, and then place it in a normal temperature environment to observe whether the coating peels off, cracks, etc.

The above is the main process for inspecting plastic-coated steel pipes. These steps are designed to ensure that the quality of plastic-coated steel pipes complies with relevant regulations and standards.

Editor: Lucas

Mail: lucas@yangtzesteel.com