What are the specifications of the Steel tube?

(1) Specifications: The specification requirements of spiral steel pipes should be specified in the import and export trade contract. Generally, it should include the standard grade (type code), the nominal diameter of the steel bar, the nominal weight (mass), the specified length and the tolerance value of the above indicators. China's standards recommend a spiral steel pipe series with a nominal diameter of 8, 10, 12, 16, 20 and 40mm. The supply length is divided into two types: fixed length and double ruler. China's export rebar sizing selection range is 6~12m, and Japan's rebar sizing selection range is 3.5~10m.

(2) Appearance quality: (1) Surface quality. The relevant standards stipulate the surface quality of rebar, requiring that the end should be cut straight, the surface should not have cracks, scars and folds, and there should be no harmful defects in use; (2) The allowable value of external dimension deviation. The requirements for the bending degree of rebar and the geometry of the rebar are specified in the relevant standards. As stipulated by China's standards, the bending degree of straight steel bar is not more than 6mm/m, and the total bending degree is not greater than 0.6% of the total length of the steel bar.