Four point bending over bending straightening process method for large shaft tube parts
The invention relates to a four point bending over bending straightening process method for large shaft tube parts and is characterized in that two lower dies are arranged on a workbench of a forming press, two upper dies are connected to a beam of the forming press, and a shaft tube part is placed among the two upper dies and the two lower dies under the beam of the forming press; the distance between the two lower dies is determined by calculation, the distance between the two upper dies is determined by calculation, and the positions of the upper dies above the lower dies, and the rolling reduction of the two upper dies are determined by calculation; the distance between the two upper dies and the distance between the two lower dies are respectively adjusted to the expected position; then, the shaft tube part is pressed, after the pressing is finished, the upper dies move upwards along with the beam of the forming press; and whether the straightness of the shaft tube part meets requirements or not is inspected, if not, the steps are repeatedly carried out until the requirements are met. The four point bending over bending straightening process method for the large shaft tube parts has the advantages that the finally finished shaft tube part is deformed uniformly and realizes smooth transition, and the straightness of the parts better meets the requirements; residual stress existing in the parts is smaller, and the distribution of the residual stress is uniform; and meanwhile, the forming cycle is shortened, and the working efficiency is improved.