Also known as square and rectangular coldbendinghollowsection,referredto as "square and rectangular tubes,code FandJ,respectively 1,the allowable deviation in the wallthicknessofthemoment, when thewall thickness is not more than 10 mmshallnotexceedthe nominal wallthickness of plus or minus 10%,whenthewallthickness is more than 10mm for the wall thickness ofplusorminus8%, except corners and weldarea wall thickness. 2,thetorquetubeusually delivery length is 4000 mm- 4000 mm, 6000 mm and12000mminthe majority. Torque tube allowdelivery not less than2000mmshortfeet and the length of the product,can alsointerfacetubeformdelivery, but the buyer when use interfacetubeshouldberemoved.Short feet and non scale product weight is notmore than5%ofthetotal amount of delivery, for theoretical weightgreaterthan20kg/msquare torque tube shall not exceed 10% of thetotalamountofdelivery3, square torque tube bending shall not be greaterthan2 mmpermetre,total bending shall not be greater than 0.2% of thetotal length