YUHONG GROUP - High Frequency Welded Finned Tube

The welding of high-frequency welded spiral finned tube is roughly divided into the following processes:

(1) Purchase and re-inspection of steel pipe:

steel pipe should be purchased in accordance with the standards and technical terms required by the drawings; back to the factory must be carefully re-inspected, re-inspection should include: checking the quantity, specifications, whether the material is in line with the relevant material certificates, the various inspection reports are complete and effective; root-by-root for the appearance and geometric size check, respectively, according to the furnace, batch number sampling of the chemical composition and mechanical properties of the material; for the materials that have Root-by-root requirements for ultra-probe materials, should be drawn at least 10% for ultra-probe sampling and so on;

(2) Fin winding and welding before preparation:

the surface state of the steel tube must be conducive to the winding of the sheet, the surface of the bare tube should be free of pits, dents, iterations, grooves. Before welding, the outer surface of the base tube must be cleared of oxides, grease and impurities affecting the quality of welding and overcoating, usually by polishing or sandblasting. Finned tube winding fins, using thin steel plate open strip, according to the required fin height of the entire roll of thin steel plate cut to the required width;

(3) Fin winding welding:

the steel tube to be wound is mounted on the fin winding welding machine, and the fins are welded according to the qualified winding and welding process, and the finned tube is welded on the fixed guide rail while travelling until it reaches the required welding length

(4) Inspection and test:

the winding of the finned tube root by root for the appearance of the inspection and scraping sound, peeling inspection, the test results should be consistent with the drawings and technical requirements. Then root by root for hydraulic test, test pressure according to the design pressure 1.5 times or drawings, holding time of not less than 5 min;

(5) Fin protection:

Finned tubes are blown clean with compressed air after manufacturing. Qualified finned tubes are confirmed by inspection; carbon steel and alloy steel finned tubes are sprayed with anticorrosive paint on the outer surface, and stainless steel finned tubes are sprayed with varnish on the surface; both ends of the finned tubes are protected with caps to prevent water and sundries from entering the tubes.