In general, the diameter of the spiral steel pipe tube can be divided into outer diameter, inner diameter, nominal diameter. Pipe material for the spiral steel pipe pipe outside diameter with the letter D to indicate, followed by additional outer diameter of the size and wall thickness, for example, the outer diameter of 108 seamless steel pipe, wall thickness of 5MM, with D108 * 5, said the plastic pipe is also expressed in terms of the outer diameter, such as De63, others, such as reinforced concrete pipe, cast iron pipe, galvanized pipe and so on, using DN, in the design drawings are generally used to indicate the nominal diameter, nominal diameter is In order to design, manufacture and maintenance of the convenience of artificially stipulated a standard, but also more nominal diameter, is the name of the specifications of the pipe (or fittings).

In recent years, with the continuous upgrading of the welding process of large diameter spiral steel pipe (SSAW), its processing quality and process performance will be significantly improved. There will be a very big gap between the quality of such pipes sold on the market after the variety of such pipes is increasing. What can determine the quality of large diameter spiral steel pipe?

Welded steel pipe slag is residual inside the weld slag. Theoretically analyzed, submerged arc automatic welding weld slag produced by the following three main reasons: ① raw materials (including base metal, wire, flux) inclusions more; ② multi-layer welding layer cleaning is not clean; ③ selection of welding process parameters are not appropriate, is not conducive to the emergence of slag.

Spiral pipe is generally sent to the hands of the user production workshop is not put so much spot, which requires the dealer to place some spot. However, dealers generally do not have a large indoor warehouse, most of them are outdoor warehouses, spiral pipe in the outdoor put can not avoid the wind and sun. So, how to distinguish between floating rust and rust of spiral pipe?

Spiral welded pipe is frankly also a spiral steel pipe is called, generally refers to the diameter of more than 1 meter spiral steel pipe. Steel pipe should be hydrostatic, bending, flattening and other experiments, the surface quality has certain requirements, usually delivery length of 12 meters, often require fixed-foot delivery.