Method for molding and manufacturing metal pipe

Abstract

The invention relates to a method for molding and manufacturing a metal pipe, wherein the pipe is preformed into a crude pipe blank so as to implement a hot gas molding method. The hot gas molding method comprises the following steps of: firstly, preheating the crude pipe blank to reach a proper molding temperature; secondly, placing the crude pipe blank into a molding mould which is heated to reach the set temperature; thirdly, sealing both ends of the crude pipe blank, injecting high-pressure gas into the crude pipe blank, and propelling the both ends of the crude pipe blank as pushing compensation when the pressure of the high-pressure gas reaches the set pressure, so as to mold an outline of the crude pipe blank; and fourthly, taking out the crude pipe blank for post-processing to mold and manufacture a finished pipe product. Therefore, in the production process, not only the outline of the pipe can be easily molded to meet the design requirements of various outlines, but also the rebound phenomenon can be reduced so as to guarantee the size accuracy. Moreover, the pressure of the working gas can be greatly reduced. Consequently, the advantages of easiness of molding and manufacturing and saving of equipment cost can be achieved.

Description

technical field [0001] The invention relates to a method for forming pipe fittings that can easily form the outline of pipe fittings, ensure dimensional accuracy, and can greatly reduce the pressure of working gas to achieve easy molding and save equipment costs. Background technique [0002] In industries such as automobiles, locomotives, bicycles, and aerospace industries, the appearance of the products or metal pipe fittings that need to be assembled, under the consideration of function and aesthetics, the diameter of the pipe fittings will be tapered or tapered. Irregularly changing appearance such as expansion. [0003] see figure 1 , figure 2 , image 3 As shown, it is China Taiwan Announcement No. 546225 "Seamless Vehicle Frame Forming Method" invention patent case, which is to draw a hollow tube body into a rough embryo tube 10 of a predetermined shape, and then draw the rough embryo tube 10 The tube 10 is placed in a mold 20 with upper and lower molds 21, 22, a...

AI Technical Summary

Problems solved by technology

[0004] The described forming method utilizes hydraulic pressure to form the outline of the rough embryo tube 10, and must be operated at normal temperature. Because the elongation rate of the metal material is low at normal temperature, the formability of the rough embryo tube 10 will be poor. However, it is difficult to form a shape with a large change in pipe diameter or a small rounded corner at the bend, which limits the shape design of the pipe fittings

[0005] The molding method is to shape the outline of the rough embryo tube 10 at normal temperature, which will cause a lot of residual stress in the rough embryo tube 10, and after molding, irregular rebound phenomenon is very likely to occur, and it is difficult to ensure the size of the rough embryo tube. The precision, which in turn causes troubles in molding

[0006] The described forming method is to form the outline of the rough embryo tube 10 under the normal temperature state. Although it uses the pressurized cylinders 25, 26 for pressurization and pushing compensation when forming, yet the metal material is under the normal temperature state. The tube material that can be compensated is limited, and after forming, the tube wall at the bulge will be thinner, and the overall tube wall thickness of the rough embryo tube 10 will be uneven, which will affect the overall strength

[0007] The forming method is to form the outline of the rough embryo tube 10 at normal temperature. If the rough embryo tube 10 is made of general metal material, the pressure value must usually reach 2000 Bar, which is enough to make the rough embryo tube 10 bulge and deform. For some rough embryo tubes 10 made of high-strength special metals, the pressure value must even reach 3,000-4,000 Bar. Therefore, the pressure required for its molding is quite high, which in turn greatly increases the cost of molding equipment

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