The welding of high frequency welding finned tube is roughly divided into the following processes:
(1) Purchasing and re-inspection of steel pipes: The steel pipes should be purchased in accordance with the standards and technical terms required by the drawings; re-inspection must be carried out carefully after returning to the factory. The re-inspection content should include: checking whether the quantity, specifications, and materials are consistent, and the relevant material certification Whether the materials and various inspection reports are complete and valid; check the appearance and geometric dimensions one by one, and sample the chemical composition and mechanical properties of the materials according to the furnace and batch number; for the materials that require super-detection, at least 10% should be sampled. Super probe spot check etc.
(2) Preparation before fin winding and welding: The surface of the steel pipe must be conducive to the winding, and the surface of the smooth pipe should be free of pits, dents, overlaps, and grooves. Before welding, the oxides, grease, impurities, and coatings on the outer surface of the base pipe must be removed, usually by polishing or sandblasting. The fins used for fin tube winding are made of thin steel plates, and the entire roll of thin steel plates is cut to the required width according to the required fin height.
(3) Fin winding welding: the steel pipe to be wound is installed on the fin winding welding machine, and the fins are welded according to the qualified winding welding process. The fin tube is welded while traveling on the fixed guide rail until it reaches the required value. Up to the required welding length.
(4) Inspection and test: Carry out a visual inspection, scratching, and peeling inspection of the wound fin tubes one by one, and the inspection results should meet the drawings and technical requirements. Then carry out the water pressure test one by one. The test pressure shall be 1.5 times the design pressure or the requirements of the drawing, and the pressure holding time shall not be less than 5 min.
(5) Fin protection: After the fin tube is manufactured, blow it clean with compressed air. The finned tube confirmed by inspection; the outer surface of the carbon steel and alloy steel finned tube is sprayed with anticorrosive paint, and the surface of the stainless steel finned tube is sprayed with varnish; both ends of the finned tube are protected by caps to prevent water and debris from entering the tube.
Finned tube manufacturers