Spiral steel pipe size, shape, weight and allowable deviation

Spiral steel pipe size, shape, weight and allowable deviation

1) Nominal diameter range and recommended diameter The nominal diameter range of steel bars is 6 to 25mm. The standard nominal bar diameters recommended are 6, 8, 10, 12, 16, 20, 25, 32, 40, and 50mm.
2) Permissible variations in surface shape and dimensions of ribbed steel plates Rib bars in transverse ribs are to comply with the following basic requirements:
The angle β between the transverse ribs and the axis of the steel plate shall not be less than 45 degrees. When the included angle is not more than 70 degrees, the direction of the transverse ribs on the opposite sides of the steel bars shall be opposite;
The transverse rib and spacing l shall not be greater than 0.7 times the nominal diameter of the steel bar;
The angle between the side of the transverse rib and the surface of the steel bar shall not be less than 45 degrees;
The sum of the gap (including the width of longitudinal ribs) between the ends of the transverse ribs on the opposite sides of the reinforcing bar shall not exceed 20% of the nominal circumference of the reinforcing bar;
When the nominal diameter of the steel bar is not more than 12mm, the relative rib area shall not be less than 0.055; the nominal diameter shall be 14mm and 16mm; the relative rib area shall not be less than 0.060; when the nominal diameter exceeds 16mm, the relative rib area shall not be less than 0.065.
3) Length and Permissible Deviation a, Length: Steel bars are usually delivered according to the length of the fixed length. The specific delivery length should be specified in the contract. When the steel bars are delivered in coils, each plate should be a steel bar, allowing each batch to have The number of discs for 5% (two discs for less than two discs) consists of two bars. Its disk weight and disk diameter are negotiated between supply and demand parties.
b. Permissible length deviation: The allowable deviation of the length of steel bars delivered by fixed length shall not be greater than +50 mm.
c. Bend and end: The bending of the straight bar should not affect the normal use. The total bending is not more than 40% of the total length of the bar. The end of the bar should be cut straight, and the local deformation should not affect the use.