Profile Forging Method of Large Cylinder Forging with Inner and Outer Steps

Abstract

The invention discloses a profiling forging method of a large cylinder forge piece provided with internal and external steps. According to the profiling forging method of the large cylinder forge piece provided with the internal and external steps, raw material consumption and machining allowance can be reduced under the premise that internal quality is guaranteed. The profiling forging method comprises steps as follows: A, tongs hold is performed; B, rolling, drawing and blanking are performed; C, upsetting and punching are performed; D, a common mandrel is subjected to pre-reaming until a step saddle can penetrate into a forging stock; E, step saddle pre-drawing is adopted to enable an inner hole of the forging stock to form the step, an outer contour of the forging stock forms a step cylinder shape, and meanwhile, the length of the forging stock meets the technical processing size; F, the step saddle and a step reaming anvil are adopted for hole reaming forming. With the adoption of the profiling forging method, natural streamline of metal can be prevented from being cut off, so that fibers of the forge piece are continuous, and improvement of synthesized mechanical properties of the forge piece is facilitated.

Description

technical field [0001] The invention relates to forging technology, in particular to a profiling forging method of a large cylinder forging with internal and external steps. Background technique [0002] It is known that large-scale cylinder forgings with inner and outer steps are used in nuclear power, petrochemical and deep-sea pressure vessels. Because the equipment is a forged-welded structure, the original design is to separate the flange and the cylinder body, and finally weld them together. With the increasing size of containers and the continuous improvement of technical requirements, it has become a consensus to minimize welds, which can improve the safety, reliability and service life of equipment, and at the same time reduce the in-service inspection of nuclear power and other products times and risks. Therefore, at present, the flange and the barrel section of this forging have been designed as a whole, thus forming a special large-scale barrel structure with do...

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Problems solved by technology

[0006] 2) The size of the forging is huge and the weight is overweight. During the forging process, the equipment is in a state of extreme load, which poses a great obstacle to the process control, especially the control of the billet precision

[0007] 3) Due to the inconsistent wall thickness at both ends of the forging, it is easy to form a bell mouth during the deformation process, and the wall thickness is too thick when it is pulled out, and it is easy to form a concave center

[0009] 5) The metal at the root of the flange and the barrel section is in a transitional position during the reaming deformation process, which cannot be synchronized with the flange end or the barrel section end, so it is easy to form a "waist" defect

[0010] 6) During the deformation process, the material of the flange section is slow, and the material of the connecting cylinder section is fast, so it is easy to form a situation where the size of the connecting cylinder section is in place but the flange section is still insufficient

[0015] ①The traditional process method adopts forging in the form of simplified forging diagram. Although the difficulty of forging and forming is reduced, the weight of forgings is greatly increased, and the input of raw materials and machining tables are increased. Moreover, as container products are becoming more and more large-scale, The problems brought about by this method are not only cost and cycle problems, but more seriously, too much dressing will greatly expand the size of the steel ingot, which has limited the production and feeding, and will seriously restrict the large-scale production.

[0016] ②The internal and external steps of the forging are processed by machining, which cuts off the natural flow line of the metal, and a large part of the dense forging surface is processed in vain, which is not conducive to the comprehensive performance of the forging

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