The roll machine has a roll diameter of φ255, a lower roll diameter of φ150, a lower roll center distance of 245, and a main motor power of 7.5 kW. The machine belongs to the hydraulic three-roller bending machine. The upper roller can move vertically and horizontally, and the lower roller is fixed. Each lower roller has two sets of rollers to improve the rigidity of the lower roller and facilitate feeding and operation. The hydraulic system uses imported oil pumps and hydraulic components. The control system adopts imported industrial computer, CRT screen display, with two sets of manual plus automatic control.