Also known as square and rectangular cold bending hollow section,referred to as "square and rectangular tubes, code F and J,respectively 1, the allowable deviation in the wall thickness of themoment, when the wall thickness is not more than 10 mm shall not exceedthe nominal wall thickness of plus or minus 10%, when the wallthickness is more than 10 mm for the wall thickness of plus or minus8%, except corners and weld area wall thickness. 2, the torque tubeusually delivery length is 4000 mm - 4000 mm, 6000 mm and 12000 mm inthe majority. Torque tube allow delivery not less than 2000 mm shortfeet and the length of the product, can also interface tube formdelivery, but the buyer when use interface tube should be removed.Short feet and non scale product weight is not more than 5% of thetotal amount of delivery, for theoretical weight greater than 20 kg/msquare torque tube shall not exceed 10% of the total amount of delivery3, square torque tube bending shall not be greater than 2 mm per metre,total bending shall not be greater than 0.2% of the total length