Square and rectangular tubes, also known as equal-sided steel pipes. They are formed by rolling steel strips through a process. Typically, steel strips are unpacked, leveled, rolled, and welded into round tubes, which are then rolled into square tubes and cut to the required length. Usually packed in 50 pieces per bundle.

Also known as square and rectangular cold-formed hollow sections, commonly referred to as square tubes and rectangular tubes, with designations 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 square tubes typically range from 4000mm to 12000mm, with 6000mm and 12000mm being the most common. Square tubes may be delivered in lengths of less than 2000mm and non-standard sizes, or in the form of joint tubes, which the customer should cut off upon use. The weight of short lengths and non-standard products should not exceed 5% of the total delivery quantity, and for square tubes with a theoretical weight greater than 20kg/m, this should not exceed 10% of the total delivery quantity.

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