Square pipe is a name for square pipe and rectangular pipe, that is, steel pipe with equal and unequal side lengths. It is made of rolled strip steel after process treatment. Generally, the strip steel is unpacked, leveled, crimped and welded to form a round pipe, then rolled into a square pipe, and then cut into the required length.
1. The allowable deviation of the wall thickness of square pipe 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.
2. The usual delivery length of square pipe is 4000mm-12000mm, mostly 6000mm and 12000mm. The square tube is allowed to deliver short and non fixed length products not less than 2000mm, or in the form of interface tube, but the Demander shall cut off the interface tube when using it. The weight of short length and non fixed length products shall not exceed 5% of the total delivery volume. For square tubes with theoretical weight greater than 20kg / m, it shall not exceed 10% of the total delivery volume
3. The bending degree of square pipe shall not be greater than 2mm per meter, and the total bending degree shall not be greater than 0.2% of the total length