The construction of the polyethylene coating of the three-layer structure of the anti-corrosion seamless steel pipe is generally carried out on the factory production line. It is designed based on the combination of online anti-corrosion equipment. The coating of the three-layer system should be carried out in accordance with the technical specification procedures. At present, the equipment on the three-layer coating production line is controlled by computers. The coating thickness is adjusted as needed to automatically process and coat the steel pipe. At the same time, the coating status of the coated pipe section is recorded, as well as the inspection for missing coatings. The final inspection and test results of the coating process should be comprehensively analyzed, including surface roughness and cleanliness, whether there is any missed coating, impact resistance, adhesion, covering layer thickness, stretchability, cross-section, and detection of cured cathode peeling, pressure fracture resistance, etc. Technical parameters such as resistivity and ultraviolet resistance of the elongation covering layer can be used to observe and evaluate its quality characteristics, and to achieve and control the external anti-corrosion quality of pipelines cost-effectively.
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r Three-layer structure polyethylene anti-corrosion coating The three-layer structure polyethylene anti-corrosion coating is based on many years of practical experience in pipeline anti-corrosion, combining the excellent epoxy resin powder from North America and Europe An anti-corrosion coating system that combines polyethylene barrier protective layers began to be promoted globally in the mid-2000s. The structure of the three-layer polyethylene anti-corrosion coating is divided into three parts, namely, the epoxy resin base primer, the intermediate polymer binder coating and the outer polyhexene surface coating. In the actual coating process, the structure of the three anti-corrosion coatings should be selected according to the operating temperature of the pipeline and the coating equipment.
Process inspection and test requirements The quality inspectors of each station should conduct inspections according to the inspection and test items and inspection procedures stipulated in the contract. All inspections should comply with the requirements stipulated in the contract. ●Inspection items that have not been inspected or have not fully completed the process requirements shall not be transferred to the next process. ●If a test item that does not belong to this inspection station is found to be unqualified, the quality inspector of this station will track the pipe and notify the quality inspectors of each subsequent station. ●When a fault occurs and normal inspection cannot be carried out, it should be marked and stored in a designated location. Only after passing the inspection can it be transferred to the next process. Mark the unqualified products accordingly and fill in the reasons for the unqualified products in the records. After coating, the product must complete the inspection and test items specified in each process and meet the specified requirements. Coated steel pipes should be judged according to the standards required by the owner, and inspection records and inspection status markings should be made. Substandard pipes permitted by standards can be repaired. Pipes that are unqualified after repair and cannot be repaired will be deemed as waste pipes and will be centrally disposed of by the Production Technology Department.
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r Epoxy resin powder has high adhesion, good cathode stripping resistance, chemical barrier properties and antioxidant properties. The polymer coating has excellent chemical adhesion to the epoxy base layer, resisting shear forces caused by soil movement and temperature changes. The high-density polyethylene surface coating has a good barrier effect against moisture, can protect the epoxy resin bottom layer and polymer coating, has strong resistance to mechanical damage, reduces peeling, has low cathodic protection current, and can adapt to a wide temperature range of ~℃. The combination of the three-layer polyethylene anti-corrosion coating is characterized by the best combination and reinforcement between the three coatings. The three layers of coating have strong chemical adhesion. The performance and characteristics of each layer make the three layers Paints are complemented. This three-layer anti-corrosion coating is composed of a three-in-one form and optimizes the overall chemical and mechanical properties. It combines the good adhesion and chemical resistance of epoxy resin and the mechanical strength and mechanical strength of polyethylene coating. It has a protective effect and is widely used in anti-corrosion projects for metal pipelines such as oil, gas and water.
3pe anti-corrosion seamless steel pipe