A sample about 100 mm in length was cut from any position of the plastic-coated fire pipe, and the impact test was carried out according to the provisions in Table 2 at the temperature of (20±5) ℃ to observe the damage of the inner coating. During the test, the weld shall be in the opposite direction of the impact surface, and the test result shall comply with the provisions of 5.9.
Impact test conditions
Nominal diameter DN
Mm hammer weight, kg falling height, mm
15-251.0300
32 ~ 502.1500
65
80 ~ 3006.31000
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, and gradually increase the negative pressure from the inlet to 660 mm hg, keep it for 1 min. After the test, check the inner coating, and the test results should comply with the provisions of 5.10.
High temperature test
The length of the pipe section specimen was (100±10) mm. The specimen was placed in the incubator and heated to (300±5) ℃ for 1 h. Then it was removed and cooled naturally to normal temperature. After the test, take out the specimen and check the inner coating (darker and darker appearance is allowed), and the test results should comply with 5.11.
Pressure cycle test
The length of the pipe section specimen was (500±50) mm. Appropriate measures were used to block the inlet and outlet of the pipe, and the pipe was connected with the water supply system. Water was filled to remove air, and then 3000 alternating hydrostatic tests from (0.4±0.1) MPa to MPa were carried out, and the period of each test was not more than 2 s. After the test, the inner coating shall be checked and the adhesion test shall be carried out according to the provisions of 6.4, and the test results shall conform to the provisions of 5.13.
Temperature cycle test
The length of the pipe section specimen was (500±50) mm. The specimens were placed for 24 h at each temperature in the following order:
(50±2) ℃;
(-10±2) ℃;
(50±2) ℃;
(-10±2) ℃;
(50±2) ℃;
(-10±2) ℃.
After the test, the specimen was placed in an environment with a temperature of (20±5) ℃ for 24 h. The inner coating was checked and the adhesion test was carried out according to the provisions of 6.4. The test results should conform to the provisions of 5.14.
Warm water aging test
The size and length of the pipe section specimen is about 100 mm. The exposed parts at both ends of the pipe section should be treated with anticorrosion. The pipe section should be soaked in distilled water at (70±2) ℃ for 30 days.
Features overview editor broadcast
(1) High mechanical properties. Epoxy resin has strong cohesion and compact molecular structure, so its mechanical properties are higher than phenolic resin and unsaturated polyester and other universal thermosetting resins.
(2) Plastic fire pipe coating using epoxy resin, with strong adhesion. The curing system of epoxy resin contains extremely active epoxide group, hydroxyl group, ether bond, amine bond, ester bond and other polar groups, endowing the epoxy cured material with excellent adhesion to metal, ceramic, glass, concrete, wood and other polar substrates.
(3) curing shrinkage rate is small. Generally 1% ~ 2%. It is one of the varieties with the smallest curing shrinkage in thermosetting resin (phenolic resin is 8% ~ 10%; Unsaturated polyester resin is 4% ~ 6%; Silicone resin 4% ~ 8%). Linear expansion coefficient is also very small, generally 6×10-5/℃. So the volume changes little after curing.
(4) Good technology. Epoxy resin curing basically does not produce low molecular volatiles, so can be low pressure molding or contact pressing molding. It can cooperate with all kinds of curing agent to produce solvent-free, high solid, powder coating and water-based coating and other environment-friendly coatings.
(5) Excellent electrical insulation. Epoxy resin is a thermosetting resin with good antistatic properties.
(6) Good stability, excellent resistance to chemicals. Epoxy resin without alkali, salt and other impurities is not easy to deteriorate. As long as it is stored properly (sealed, not affected by moisture, not in high temperature), its storage period is 1 year. It can still be used if it is qualified after the expiration. Epoxy cured materials have excellent chemical stability. Its corrosion resistance of alkali, acid, salt and other media is better than unsaturated polyester resin, phenolic resin and other thermosetting resin. Therefore, epoxy resin is widely used as anticorrosive primer, and because epoxy resin curing material is three-dimensional network structure, and can withstand the impregnation of oil, etc., a large number of applications in oil tank, oil tanker, aircraft, the inner wall lining of the overall tank.
(7) Epoxy curing heat resistance is generally 80 ~ 100℃. Epoxy resin heat resistant varieties can reach 200℃ or higher.
Product advantages
(1) Coated plastic steel pipe has high mechanical strength, suitable for harsh use environment;
(2) The inner and outer coating can prevent metal oxidation and has good chemical corrosion resistance;
(3) the coating has strong adhesion, high bonding strength and good impact resistance;
(4) Low roughness coefficient and friction coefficient, excellent resistance to foreign body adhesion;
(5) Coated steel pipe is anti-aging and has long service life, especially suitable for underground water delivery.
Post time: May-23-2022