Hot heading molding process for large-size torsion bar of bullet train

Abstract

The invention discloses a hot heading molding process for a large-size torsion bar of a bullet train. The hot heading molding process comprises the following steps of 1, blanking, wherein a round barmaterial is selected, a part, needing to be machined, of a head of a round bar is divided into a first part and a second part which are the same in length, and the height-diameter ratio of the first part to the second part is less than or equal to four; 2, heating and upsetting, wherein the first part is heated, pressing and positioning are conducted on a middle bar portion through a horizontal forging machine and a vertically-pressing mold, and a movable mold for the head is closed for local molding; 3, premolding, wherein the second part is heated, pressing and positioning are conducted on the middle bar portion through the horizontal forging machine and the vertically-pressing mold, and the movable mold for the head is closed for molding; 4, molding, wherein the step 2 and the step 3 are repeated till heading of the two ends is completed; and 5, machining, wherein finish machining is conducted on a forged piece according to requirements. According to the hot heading molding process,the local heating and molding mode is adopted; when the height-diameter ratio is eight, heading can be conducted on the ends; heading is conducted on a blank through the movable mold and the vertically-pressing mold; and under the condition that the height-diameter ratio achieved in the one-time upsetting process is four, bending and folding caused in the heading process are prevented.

Description

technical field [0001] The invention relates to the field of forging, in particular to a hot heading forming process for a large torsion bar of a train. Background technique [0002] In the anti-rolling device of the EMU, it is usually necessary to use a torsion bar. The torsion of the torsion bar is mainly used to prevent the rollover of the vehicle. The material of this torsion bar is 52CrMoV4, the length of the parts is 2680mm, and the maximum diameter of both ends 80mm, and the diameter of the rough machining size of the rod is 70mm, which is the largest torsion bar at present. [0003] The original similar torsion bar head has a diameter of up to 70mm after rough machining, and is processed by forging circle turning. This processing method has low material utilization rate, large machining allowance, and high manufacturing cost, and the fiber metal flow is cut off at the step transition. Line, the scheme is not advisable, and there are similar products whose diameter a...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a hot heading forming process for large torsion bars of motor vehicles, so as to solve the problems of high manufacturing cost, low material utilization rate, long processing time of forgings, and cutting of metal fiber streamlines caused by turning processing.

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