Also known as square and rectangular cold bending hollowsection,referredto as "square and rectangular tubes, code F andJ,respectively 1,the allowable deviation in the wall thickness ofthemoment, when thewall thickness is not more than 10 mm shall notexceedthe nominal wallthickness of plus or minus 10%, when thewallthickness is more than 10mm for the wall thickness of plus orminus8%, except corners and weldarea wall thickness. 2, the torquetubeusually delivery length is 4000 mm- 4000 mm, 6000 mm and 12000 mminthe majority. Torque tube allowdelivery not less than 2000 mmshortfeet and the length of the product,can also interface tubeformdelivery, but the buyer when use interfacetube should beremoved.Short feet and non scale product weight is notmore than 5% ofthetotal amount of delivery, for theoretical weightgreater than 20kg/msquare torque tube shall not exceed 10% of the totalamount ofdelivery3, square torque tube bending shall not be greater than2 mm permetre,total bending shall not be greater than 0.2% of the total length