Plastic coated steel pipe is the product of PE(modified polyethylene) for hot dip plastic or EP(epoxy resin) for internal and external coating, which has excellent corrosion resistance. At the same time, the coating itself also has good electrical insulation, and will not produce electrical corrosion. Low water absorption, high mechanical strength, and small friction coefficient can achieve the purpose of long-term use. It can also effectively prevent damage to plant roots and soil environmental stress. Convenient connection and easy maintenance.

Test method for plastic coated steel pipes

1. Appearance inspection

Visual inspection of the appearance quality of coated steel pipe, test results should conform to the provisions of 5.1.

2. Thickness measurement

Take two cross-sections of different lengths from the two ends of the coated steel pipe, and measure the coating thickness of any four points directly intersecting the circumference of the circle with an electromagnetic thickness meter in each cross-section.

3. Pinhole test

The length of the pipe section specimen is about 1000mm. The coating of the steel pipe is checked with the spark leak detector under the specified test voltage. The coating thickness is not more than 0.4mm, the test voltage is 1500 V, and the coating thickness is more than 0.4mm, and the test voltage is 2000V. Check whether an electric spark is generated.

4. Adhesion test

The adhesion test shall be carried out according to 7.4.2 of CJ/T 120-2008, and the test results shall comply with the provisions of 5.6.

5. Bending test

The coated steel pipe DN≤50mm shall be subjected to a bending test. The length of the pipe section specimen was (1200±100)mm.

At the temperature of (20±5) ℃, the curvature radius is 8 times the nominal diameter of the steel pipe, and the bending Angle is 30°. The bending is carried out on the pipe bender or die. During the bending test, there is no filling in the tube, and the weld is located on the side of the main bending surface.

After the test, the specimen is cut open from the middle of the bending arc to check the inner coating. The test results should conform to the provisions of 5.7.

6. Squishing test

DN> The 50 mm coated steel pipe was subjected to a flattening test. The length of the pipe section specimen was (50±10) mm.

At the temperature of (20±5) ℃, the specimen was placed between the two plates, and the distance between the two plates was gradually compressed on the pressure test machine to four-fifths of the outer diameter of the specimen. The coated steel pipe welding seam was perpendicular to the direction of load application when flattening.

7. Squishing test

8. Impact test

A sample of about 100mm in length was cut from any position of the coated steel pipe, and the impact test was carried out at the temperature of (20±5) ℃ to observe the damage to the inner coating. During the test, the weld should be in the opposite direction of the impact surface, and the test results should meet the requirements.

9. Vacuum test

The length of the pipe section specimen is (500±50) mm. Use appropriate measures to block the inlet and outlet of the pipe, gradually increase the negative pressure from the inlet to 660mm hg, keep it for 1min, and check the inner coating after the test, and the test results should meet the provisions of 5.10.

10. High-temperature test

The length of the tube section specimen was (100±10) mm. The specimen was placed in an incubator, heated to (300±5) ℃ and kept at constant temperature for 1h, and then removed and cooled naturally to room temperature. After the test, take out the specimen and check the inner coating (allow the appearance of dark color, dark phenomenon), the test results should meet the requirements.

11. Low-temperature test

The size and length of the pipe section specimens were (100±10) mm. The specimens were placed in a cryogenic chamber, cooled to (-30±2) ℃, and kept at a constant temperature for 1h. Then, the specimens were taken out and placed in an environment with a temperature of (20±5) ℃ for (4-7) h.

12. Pressure circulation test

It was connected with the water pressure supply system, filled with water to remove air, and then carried out 3000 alternating hydrostatic tests from (0.4±0.1) MPa to MPa, with a cycle of no more than 2s for each test. After the test, check the inner coating, and carry out the adhesion test according to 6.4. The test results should meet the requirements.

13. Temperature cycle test

The length of the pipe section specimen was (500±50)mm. The specimens were placed for 24h at each temperature in the following order:

(50±2) ℃;

(-10±2) ℃;

(50±2) ℃;

(-10±2) ℃;

After the test, the specimen was placed at the temperature of (20±5)℃ for 24h to check the inner coating, and the adhesion test was carried out according to the provisions of 6.4. The test results should meet the requirements.

14. Warm water aging test

The length of the pipe section specimen is about 100mm, and the exposed parts at both ends of the pipe section should be treated with anti-corrosion. The pipe section should be immersed in distilled water at (70±2) ℃ for 30d. After the test, the pipe section should be taken out and cooled naturally to room temperature

Cangzhou shenlong pipe manufacturing co., ltd. Is engaged in oil, gas, water, coal slurry mixing medium steel pipeline coating operations, anti-corrosion, insulation, piping is set in a body's specialized pipeline engineering precast construction enterprises, products used in an oil pipeline, chemical piping, electrical, pipe, gas pipe, heat pipes, sewage pipes, etc. Anti-corrosion processing of straight pipe and bend pipe DN40-3000 three-layer structure polyolefin (PE, PP, TPEP,3LPE) steel pipe coated with anti-corrosion, DN40-3800 steel hot stewed bend pipe and pipe fittings coated with FBE, epoxy resin coating anti-corrosion, DN40-3800 steel pipe inner wall resistance reduction, solvent-free epoxy steel pipe, epoxy paint anti-corrosion, Coated plastic steel pipe, dip plastic steel pipe. Lined with plastic steel pipe PE, PO, PP, PTFE, HDPE, polymer polyethylene corrosion. The company is in strict accordance with China Petroleum and Natural Gas SY/T0413-2002, national GB/T23257-2009, German DIN 30670, American AWWA C210 and other international and domestic anti-corrosion standards.