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A method for forming an internal high-pressure forming die for forming a stepped pipe fitting

A technology of internal high-pressure forming and stepped structure, which is applied in the field of plastic forming of pipe fittings, can solve the problems of increased forming pressure of sharp-edged structures, increased friction between pipes and molds, and equipment that cannot meet the requirements, so as to reduce production costs and reduce friction. Small, avoiding the effect of excessive thinning and cracking of wall thickness

Active Publication Date: 2018-06-26
DALIAN DESIGN INST CO LTD CHINA FIRST HEAVY IND +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Existing internal high pressure forming dies for pipe fittings with stepped structures are integral, and the bulging diameter, wall thickness thinning and forming fillet radius of the middle cavity can only be adjusted by changing the axial feed and internal pressure loading path. Optimization, this mold structure has an obvious disadvantage. When the bulging is basically over and the rounded corners of the forming stepped structure dominate, due to the friction between the pipe and the mold, it will be difficult to change the means of axial feed and internal pressure loading path. However, with the increase of pipe wall thickness and the application of high-strength pipes, the forming pressure of the sharp corner structure will be further increased by using the traditional internal high-pressure forming die, and even the equipment cannot meet the requirements. In addition, with the increase of forming pressure increase, the friction between the pipe and the mold also increases significantly, resulting in excessive thinning or even cracking of the wall thickness during fillet filling

Method used

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  • A method for forming an internal high-pressure forming die for forming a stepped pipe fitting
  • A method for forming an internal high-pressure forming die for forming a stepped pipe fitting
  • A method for forming an internal high-pressure forming die for forming a stepped pipe fitting

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Embodiment 1

[0042] Embodiment 1: as figure 1 As shown, the formed pipe fitting is a variable-diameter straight pipe bulging pipe fitting. The material of pipe 2 is DC04, the diameter is 60mm, the thickness is 1.5mm, the diameter of the middle bulging part is 80mm, and the length is 100mm.

[0043]The traditional internal high pressure forming die is adopted, the forming pressure is 120MPa, the left and right feed is 18mm, and the loading path is linear loading. The pipe fitting 9 formed by the internal high pressure forming process has a minimum radius of 8 mm, a minimum wall thickness of 1.036 mm, and a thinning rate of 30%.

[0044] The test piece is formed by using the internal high pressure forming mold for forming a stepped pipe fitting of the present invention, the distance s between the left and right bushings and the side wall 10 of the pipe cavity is 3 mm, the loading path is the same as that of the traditional internal high pressure forming mold, and the internal pressure only ...

Embodiment 2

[0045] Embodiment 2: as Figure 2-3 As shown, the formed pipe fitting is a bulging type pipe fitting with a complex axis. The material of the pipe 2 is DC04, the diameter is 56mm, the thickness is 1.5mm, the height of the middle forming boss 11 is 10mm, and the length is 50mm.

[0046] The traditional internal high pressure forming die is adopted, the forming pressure is 150MPa, the left and right feed is 18mm, and the loading path is linear loading. The pipe fitting 9 formed by the internal high pressure forming process has a minimum radius of 4.5 mm, a minimum wall thickness of 0.959 mm, and a thinning rate of 36.1%.

[0047] The test piece is formed by using the internal high pressure forming mold of the stepped structure pipe fitting of the present invention, the distance s between the left and right bushings and the pipe cavity side wall 10 is 4mm, the loading path is the same as that of the traditional internal high pressure forming mold, and the internal pressure only n...

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Abstract

The invention discloses an internal high-pressure forming die for forming a pipe fitting of a step structure and a forming method thereof. The die comprises an upper die body, a lower die body, a left lining, a right lining, a left puncher pin and a right puncher pin. In the early stage of forming, an initial distance exists between the left lining and the side wall of a cavity of the pipe fitting as well as between the right lining and the side wall of the cavity of the pipe fitting, and the middle expansion portion is supplemented with materials by properly increasing the axial feeding amount through the left pincher pin and the right pincher pin. In the later stage of forming, the left pincher pin and the right pincher pin stop axial feeding, the left lining and the right lining move opposite to each other, pushing force is exerted on the middle expansion portion, and the friction force between a pipe and the die is greatly reduced since the side wall of the expansion portion is incompletely attached to the left lining and the right lining. Therefore, pressure required for forming of fillets is remarkably lowered, the wall thickness is obviously decreased, and requirements for the maximum tonnage of a die closing press, the bearing capability required for the die, the reliability of a sealing structure and pressure of a supercharger are lowered while requirements for forming the pipe fitting of the step structure are met.

Description

technical field [0001] The invention belongs to the technical field of plastic forming of pipe fittings, and in particular relates to an internal high-pressure forming die for forming stepped pipe fittings and a forming method thereof. Background technique [0002] In the past ten years, increasingly severe market competition and environmental protection policies have forced the automobile manufacturing industry to change its product types to produce light-duty vehicles to achieve low fuel consumption, low emissions and ensure safety. In order to achieve this goal as effectively as possible at low cost, it is necessary to develop or use new lightweight materials, alloys or composite materials; and to develop and improve new manufacturing technologies to convert the above lightweight materials into light weight, low cost, high strength and stable quality functional structure. Since the 1990s, internal high pressure forming of pipes has been widely used in the manufacture of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21D26/047B21D26/033
CPCB21D26/033B21D26/047
Inventor 桑宝光殷文齐
Owner DALIAN DESIGN INST CO LTD CHINA FIRST HEAVY IND
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