Quick determination method of load path of fittings hydraulic formation

A loading path and hydroforming technology, which is applied in the field of hydroforming of pipe fittings, can solve the problems of increasing test costs and wasting time, and achieve the effects of saving time and test costs, uniform wall thickness distribution, and realizing feeding

Inactive Publication Date: 2009-08-19
HARBIN INST OF TECH
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Problems solved by technology

[0006] The present invention aims to solve the problem that the determination of the reasonable loading path of the hydroforming of the existing pipe fittings relies on experience and experimentation, which not only increases the test cost, but also wastes a lot of time, and provides a method for quickly determining the loading path of the hydroforming of the pipe fittings.

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  • Quick determination method of load path of fittings hydraulic formation
  • Quick determination method of load path of fittings hydraulic formation
  • Quick determination method of load path of fittings hydraulic formation

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specific Embodiment approach 1

[0016] Specific implementation mode one: the steps of this implementation mode are as follows:

[0017] Step 1: Determine the final initial internal pressure p h : The initial internal pressure is an important parameter in the hydroforming process of pipe fittings, which directly affects the division of the forming interval. According to the wall thickness of the formed tube, the diameter of the tube, and the σ of the tube material s value to calculate the initial bulging pressure p 0 (MPa), the calculation formula is:

[0018] p 0 = 1 1 - β 2 t d σ s

[0019] In the formula, t is the wall thickness of the tube blank (mm), d is the diameter of the tube blank (mm), σ s is the yield stress of the material (MPa), β is the axial stress σ z and hoop ...

specific Embodiment approach 2

[0024] Specific implementation mode two: combination Figure 5 Describe this embodiment, the difference between this embodiment and the specific embodiment is that the final initial internal pressure p h The range is 0.7p 0 ~1.3p 0 MPa. Other steps are the same as in the first embodiment. Under these conditions, pipe fittings with no cracks on the surface, smooth and flat inner and outer walls, uniform wall thickness, no defect and no deformation can be formed; the wall thickness deviation of the pipe fittings shall not exceed 10% to 14%; the completed pipe wall is at least 0.5 mm ~ 4mm; the yield rate reaches 99%.

specific Embodiment approach 3

[0025] Embodiment 3: The difference between this embodiment and Embodiment 1 lies in the final initial internal pressure p h 1.1p 0 MPa. Other steps are the same as in the first embodiment. Under these conditions, pipe fittings with no cracks on the surface, smooth and flat inner and outer walls, uniform wall thickness, no defect and no deformation can be formed; the wall thickness deviation of the pipe fittings shall not exceed 12%; the completed pipe wall is at least 0.5mm; the finished product The rate reaches 99.95%.

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Abstract

The invention provides a method for quickly determining a loading path of hydraulic forming of pipe fittings, relates to the field of pipe fitting hydraulic forming, and solves the problems that the determination of the reasonable loading path of the pipe fitting hydraulic forming depends on the experience and test exploration so as to not only increase the test cost, but also waste a large amount of time. The method comprises the following steps: firstly, calculating out the initial internal pressure by the theory and determining the forming interval; secondly, adjusting axial feed supplementary amount to carry out numerical simulation, and determining reasonable feed supplementary amount according to the calculating result; and finally, adjusting the slope factor of the loading path to obtain the reasonable loading path. The method can accurately and quickly determine the reasonable loading path of the hydraulic forming of the pipe fittings, thereby saving the time and the test cost; and the optimized reasonable loading path is adopted to effectively realize the feed supplement of the forming interval, thereby obtaining smaller wall thickness reduction rate and oppositely-even wall thickness distribution, and improving the forming limit of the pipe fittings. The loading path determined by the invention is applied to pipe fitting hydraulic forming technology.

Description

technical field [0001] The invention relates to the field of hydroforming of pipes. Background technique [0002] The hydroforming technology of pipe fittings has developed rapidly in recent years, and has been used more and more in the fields of aerospace, automobiles, weapons, etc. The parts produced by the hydroforming technology of pipe fittings have the advantages of reducing quality, saving materials, improving strength and stiffness, and reducing the number of parts and molds , Reduce production costs and other advantages. It can be used to manufacture circular, rectangular cross-section or special-shaped cross-section members that vary along the axis of the part. [0003] At present, the advanced manufacturing technology of optimized components and the reduction of structural quality have become the focus of attention of all parties. Especially in recent years, due to the cost of fuel and raw materials and the strict restrictions on automobile exhaust emissions by e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21D26/02B21D26/037
Inventor 林俊峰李峰苑世剑
Owner HARBIN INST OF TECH
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