The straightening process of the straightener is that the position of the roller is straightened by the direction of movement of the straightened product (steel pipe, bar). Two or three large active pressure rollers are rotated in the same direction by the motor, and the other Several of the small rollers are driven pressure rollers, which are rotated by the friction of the rotating round bar or pipe. In order to achieve the required compression of the product by the rollers, these small rollers can be adjusted forward or backward simultaneously or separately. Generally, the more the number of rollers, the higher the accuracy of the product after straightening. The straightening process of the straightener is that after the product is bitten by the roller, it continuously makes linear or rotary movements, so that the straightened product undergoes various compression, bending, and flattening deformations, and finally achieves the purpose of straightening.