Square and rectangular steel tubes, also known as equal-sided steel tubes, are produced by rolling strip steel through a process. Typically, the strip steel is unpacked, leveled, coiled, and welded into round tubes, which are then rolled into square tubes and cut to the desired length. Packages usually contain 50 tubes.

Also known as square and rectangular cold-formed hollow sections, commonly referred to as square tubes and rectangular tubes, with codes F and J respectively.

1. The allowable deviation for the wall thickness of square tubes: when the wall thickness is not greater than 10mm, it should not exceed ±10% of the nominal wall thickness; when the wall thickness is greater than 10mm, it is ±8% of the wall thickness, excluding the bend and weld areas.

2. Standard delivery lengths for rectangular tubes are typically 4000mm to 12000mm, with 6000mm and 12000mm being the most common. Rectangular tubes may be supplied in lengths shorter than 2000mm or non-standard lengths, and can also be delivered as jointed tubes, but the customer must remove the joints upon use. The total weight of short lengths and non-standard products should not exceed 5% of the total delivery quantity, and for rectangular tubes with a theoretical weight greater than 20kg/m, it should not exceed 10% of the total delivery quantity.

3. The bend radius of square tubes should not exceed 2mm per meter, and the total bend should not exceed 0.2% of the total length.