SSAW steel pipe is a welded steel pipe made of strip steel coil as raw material, often warmly extruded, and welded by automatic double-wire double-sided submerged arc welding process. The process properties of SSAW steel pipe include bending, surface quality, size, shape, weight and allowable deviation.
1. Bending performance of SSAW steel pipe: After bending 180 degrees with the bending center diameter specified in the following table, the surface of the bending part of the steel bar shall not be cracked.
2. Reverse bending performance of SSAW steel pipe: According to the requirements of the buyer, the steel bar can be tested for reverse bending performance. The diameter of the bending center of the reverse bending test is correspondingly increased by one steel bar diameter than that of the bending test. Bend 45 degrees in the forward direction, 23 degrees in the reverse direction, and 23 degrees in the reverse direction. After the reverse bending test, the surface of the bending part of the steel bar shall not have cracks.
3. Surface quality of SSAW steel pipe: The surface of the steel bar is allowed to have no cracks, scars and folds. The surface of the steel bar is allowed to have bumps, but it shall not exceed the height of the transverse rib, and the depth and height of other defects on the surface of the steel bar shall not exceed the allowable deviation of the size of the location.
4. Size, shape, weight and allowable deviation of SSAW steel pipe
(1) Nominal diameter range and recommended diameter
The nominal diameter of the steel bar is 6 to 25mm, and the standard recommended nominal diameter of the steel bar is 6, 8, 10, 12, 16, 20, 25, 32, 40, 50mm.
(2) The allowable deviation of the surface shape and size of the ribbed steel plateThe transverse ribs of ribbed steel bars shall meet the following basic requirements:
a.The angle β between the transverse rib and the steel plate axis should not be less than 45 degrees, and when the angle is not greater than 70 degrees, the direction of the transverse ribs on the opposite sides of the steel bar should be opposite;
b. The transverse rib and the spacing l shall not be greater than 0.7 times the nominal diameter of the steel bar;
c. The angle α between the side of the transverse rib and the surface of the reinforcement shall not be less than 45 degrees;
d. The sum of the gaps (including the width of longitudinal ribs) between the ends of transverse ribs on opposite sides of the steel bar shall not be greater than 20% of the nominal perimeter of the steel bar;
e. When the nominal diameter of the steel bar is not greater than 12mm, the relative rib area should not be less than 0.055; when the nominal diameter is 14mm and 16mm, the relative rib area should not be less than 0.060; when the nominal diameter is greater than 16mm, the relative rib area should not be less than 0.065.
(3) Length and allowable deviation
a. Length: steel bars are usually delivered in fixed length, and the specific delivery length should be indicated in the contract;When the rebar is delivered in coils, each reel shall be one rebar, allowing 5% of the reels in each batch (two reels if there are less than two reels) consisting of two rebars. The weight and diameter of the plate are determined by the negotiation between the supplier and the buyer.
b. Allowable deviation of length: the allowable deviation of the length of the steel bar when it is delivered to a fixed length shall not be greater than +50mm.
c. Bending degree and ends: The bending strain of straight steel bars does not affect the normal use, and the total bending degree is not more than 40% of the total length of the steel bars; the ends of the steel bars should be sheared straight, and the local deformation should not affect the use.