The turning rolls are the devices, which drive the cylinder-shaped (or cone-shaped) weldment to rotate with the help of the friction force between the weldment and the driving rollers. The self-aligning turning rolls are suitable for welding the round cylinder. It can regulate by itself according to the size of the cylinder. There are several specifications for the customer to choose. The self-aligning turning rolls include two groups of main and vice devices for one set, which means to four wheels for each device: self-aligning active turning rolls and self-aligning passive turning rolls. The wheel is fabricated in the inner iron core and outer rubber structure. Therefore, it is durable in use, free of any vibration. The operation of the active turning rolls is synchronously driven by the speed regulating motor through two worm gear reduction box. Thus, turing rulls can realize stepless speed variating by using ATO VFD.