Winding type 3PE anti-corrosion steel pipe Production Process Flow: In accordance with the pipeline anti-corrosion design requirements, the steel pipe anti-corrosion production adopts an integrated mechanical assembly-line approach. When necessary, production can run continuously for 24 hours. Construction personnel are organized into three-shift teams and implement shift handover procedures. Before starting production at each process stage, the preheating temperature of the steel pipe anti-corrosion coating and the coating thickness of each anti-corrosion layer are sequentially adjusted on the production line equipped with test pipe sections, based on the specific anti-corrosion thickness requirements for the three different anti-corrosion layers. Production may only commence once all parameters meet the specified requirements.

　　Visual inspection of wrapped 3PE anti-corrosion steel pipes:

　　(1) Before processing 3PE anti-corrosion steel pipes using the wrapping method, skilled workers shall visually inspect each pipe individually. They must check for serious mechanical damage, double skin, cracks, dents, and other defects. Pipes that fail inspection shall not be used; they must be clearly marked as nonconforming and returned. Only pipes that pass inspection are permitted for construction use.

　　(2) If the opening of a threaded pipe is flat, it should be promptly rounded and repaired. Pipes that cannot be repaired should be scrapped.

　　Rust removal for wrapped 3PE anti-corrosion steel pipes:

　　(1) First, use a pipe gripper to transport the anti-corrosion steel pipes to the pipe platform on the work line. Then, employ a flame heater to preheat the outer surface of the steel pipes, removing any moisture, oil, and impurities from the pipe surface. The heating temperature should be controlled between 40℃ and 60℃ to improve the quality of rust removal on the pipe surface.

　　(2) The PW-380 steel pipe shot blasting machine is used for rust removal from steel pipes. Before the steel pipe enters the shot blasting chamber, the pipe openings at both ends are sealed with pipe plugs made of rubber pads or thick sponge (if the pipe already comes equipped with pipe plugs, use its own plug to seal the openings). This prevents steel shots from flying into the pipe openings during the rust removal process, reduces steel shot loss, and ensures an adequate shot-blasting rate during pipe rust removal. After shot blasting, the surface of the steel pipe shall meet the SA2 requirement specified in Grade 5 of “Rust Grades and Rust Removal Grades for Steel Surfaces Prior to Coating” (GB/T 8923-1988). The depth of the surface anchor pattern shall comply with the instructions provided by the epoxy powder manufacturer.

　　(3) After surface pretreatment of the wrapped 3PE anti-corrosion steel pipe, all rust, oil stains, oxide scales, and other contaminants shall be removed.

　　(4) The outer surface of each steel pipe shall be inspected individually. Surface defects that could lead to coating leakage shall be ground using an appropriate method; the wall thickness after grinding must not be less than the specified value. Defective steel pipes shall be removed or repaired.

　　(5) Steel pipes with substandard rust removal quality should be promptly removed from the production line and then returned to the production line for re-rust removal.

　　The base materials for 3PE anti-corrosion steel pipes include seamless steel pipes, spiral steel pipes, and straight-seam steel pipes. The three-layer polyethylene anti-corrosion coating boasts excellent corrosion resistance, water permeation resistance, and mechanical properties, making it widely used in the petroleum pipeline industry. The quality of the anti-corrosion layer in 3PE anti-corrosion steel pipes is crucial to the service life of buried pipelines. Due to the use of different external anti-corrosion coatings, some pipelines have remained intact underground for decades without showing any signs of corrosion, while others have begun leaking within just a few years.

　　3PE anti-corrosion steel pipes refer to externally coated steel pipes featuring a three-layer polyethylene coating (mapec). They are commonly used anti-corrosion steel pipes in China. Other anti-corrosion methods include IPN8710, FBE epoxy powder coatings, and epoxy coal tar coatings. These generally refer to the anti-corrosion treatment applied to the outer surface of steel pipes. The 3PE anti-corrosion coating for steel pipes is a novel type of anti-corrosion coating that ingeniously combines European 3PE anti-corrosion coatings with the FBE epoxy powder anti-corrosion coatings widely used in North America.