Square Pipes are also known as square and rectangular cold-bent hollow steel, and are referred to as square pipes and rectangular pipes. The codes are F and J1 and allowable deviations of square pipe wall thickness. When the wall thickness is not greater than 10mm, the wall thickness shall not exceed positive or negative 10% of the nominal wall thickness. When the wall thickness is greater than 10mm, it is positive or negative 8% of the wall thickness, except for the wall thickness of the corners and weld areas. 2. The usual delivery length of square rectangular tubes is 4000mm-12000mm, mostly 6000mm and 12000mm. Square rectangular tubes are allowed to deliver short rulers and non-fixed rulers of no less than 2000mm, and can also be delivered in the form of interface tubes, but the counter should cut off the interface tube when using it. The weight of short and non-fixed scale products shall not exceed 5% of the total delivery volume, and for square tubes with theoretical weight greater than 20kg/m shall not exceed 10% of the total delivery volume. 3. The bending degree of square rectangular tube shall not be greater than 2mm per meter, and the total bending degree shall not be greater than 0.2% of the total length. Classification Report Editing Process Classification Square Resonant Pipes are divided into: hot-rolled seamless square tubes, cold-drawn seamless square tubes, extruded seamless square tubes, and welded square tubes. Among them, welded square pipes are divided into 1. According to the process, arc welding square pipes, resistance welding square pipes (high frequency, low frequency), gas welding square pipes, furnace welding square pipes 2. According to the welds, straight sea welding square pipes, and spiral welding square pipes. Material classification Square pipes are divided into: ordinary carbon steel square pipes and low alloy square pipes. 1. General carbon steel is divided into: Q195, Q215, Q235, SS400, 20# steel, 45# steel, etc. 2. Low alloy steel is divided into: Q345, 16Mn, Q390, ST52-3, etc. Production standards classification square management is divided into: national standard square management, Japanese standard square management, British standard square management, American standard square management, European standard square management, and non-standard square management.
