---

　　The allowable deviation of spiral steel pipe wall thickness shall not exceed plus or minus 10% of the nominal wall thickness when the wall thickness is not greater than 10mm, plus or minus 8% of the wall thickness when the wall thickness is greater than 10mm, except for the wall thickness of corners and weld areas. The usual delivery length of spiral steel pipe is 4000mm-12000mm, mostly 6000mm and 12000mm. Spiral steel pipes are allowed to entrust short and non fixed length products of no less than 2000mm, and can also be delivered in the form of interface pipe.

　　However, the Demander shall cut off the interface pipe when using it. The weight of short length and non fixed length products shall not exceed 5% of the total delivery volume, and the spiral steel pipe with theoretical weight greater than 20kg / m shall not exceed 5% of the total delivery volume. According to different connection modes, spiral steel pipe is divided into adhesive socket pipe fittings, elastic sealing schematic socket pipe fittings, threaded joint pipe fittings and flange connection pipe fittings. According to different processing methods, pipe fittings are divided into injection molding pipe fittings and pipe bending molding pipe fittings. Reduction coefficient of nominal pressure and temperature because plastic products are sensitive to pressure and temperature.

　　When the water delivery temperature is different, the working pressure shall be corrected according to the reduction coefficient (f) of different temperatures. The technical requirements are that the internal and external surfaces of various pipe fittings shall be smooth without delamination. Obvious bubbles, marks, cold spots, uneven color and other defects. For injection molded spiral steel pipe, the wall thickness of the main body outside the socket connection part shall not be less than the wall thickness of the pipe with the same specification and pressure grade: the average outer diameter of the pipe socket shall comply with the provisions on the average outer diameter and deviation of the pipe in.

---

Previous: Physical and chemical reactions of hot dip galvanized steel pipe during galvanizing
Next: Cause analysis of slag inclusion in welded steel pipe

---