High-pressure forming process in corrugated pipe

Abstract

The invention relates to a high-pressure forming process in a corrugated pipe. The high-pressure forming process comprises middle area forming and two-side area forming. For a corrugated pipe which is high in corrugation height, large in corrugation and difficult to form at a time, one or more corrugations in the middle are formed in sequence through internal high pressure, and due to the fact that only the middle area is provided with the corrugations, materials can be easily supplemented to the middle area on the two sides, and therefore the thinning of the middle area is reduced; after the corrugations in the middle area are formed, the corrugations on the two sides are sequentially formed from inside to outside, and the technology can greatly reduce the thinning rate of the corrugations in the middle area so that qualified products can be produced.

Description

Technical Field

[0001] The invention belongs to the technical field of internal high pressure forming, and in particular relates to a process for internal high pressure forming of a bellows. Background Art

[0002] At present, bellows are generally formed by internal high pressure forming, usually in one step. For small corrugations, there is generally no problem with formability. However, when the corrugation height is high and the corrugation is large, during the one-step forming process, due to the large number of corrugations, it is difficult for the middle area to effectively get the material on both sides, which can easily cause the corrugation in the middle area to be thinned significantly or even cracked, resulting in the inability to form qualified products. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high-pressure internal forming process for bellows. For bellows with high corrugation height, large corrugations, and difficult to form in one time, one or several corrugations in the middle are first formed by internal high pressure in sequence. Since only the middle area has corrugations, it is easier to supplement the middle area on both sides, thereby reducing the thinning of the middle area. After the corrugations in the middle area are formed, the corrugations on both sides are formed successively from the inside to the outside. This process can greatly reduce the thinning rate of the corrugations in the middle area, so as to produce qualified products.

[0004] The present invention solves the technical problem by the following technical solutions:

[0005] A bellows internal high pressure forming process, characterized in that: the process steps are:

[0006] 1) Middle area forming: First, one or several corrugations are formed in the middle by internal high pressure forming. The number of corrugations depends on the formability of the specific part and can be determined by formability simulation analysis software;

[0007] 2) Forming of the two side areas: The corrugations on both sides are formed successively from the inside to the outside. The number of formed corrugations depends on the formability of the specific parts and can be determined by formability simulation analysis software.

[0008] The advantages and beneficial effects of the present invention are:

[0009] 1. The present invention significantly reduces the thinning rate of the corrugation in the middle area. For parts that were previously difficult to form, this process greatly increases the possibility of forming the parts;

[0010] 2. The present invention can improve the qualified rate of corrugated pipe products and ensure product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the bellows product of the present invention;

[0012] Figure 2It is a schematic diagram of a product after the middle area of ​​the bellows of the present invention is formed;

[0013] Figure 3 It is a schematic diagram of the product after the two side areas of the bellows of the present invention are formed;

[0014] Figure 4 This is a diagram showing the thinning result of the one-step forming simulation of the bellows of the present invention;

[0015] Figure 5 This is a diagram of the thinning results of the bellows step-by-step forming simulation of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0017] Figures 1 to 3 Middle: 1 to 10 are the first to tenth corrugations of the corrugated pipe product respectively.

[0018] In this embodiment: Figure 1 It is a schematic diagram of a bellows product; Figure 2 A schematic diagram of a bellows after the middle area is formed; Figure 3 This is a schematic diagram of a bellows after the two side areas are formed. Figure 4 This is a simulation result diagram of thinning of a bellows in one-step forming; Figure 5 This is a simulation result diagram of thinning of a bellows formed in steps. Normally, bellows are formed by internal high pressure forming, usually in one step. For corrugations with smaller height, there is generally no problem with formability. However, when the corrugation height is high and the corrugation is large, during the one-time forming process, due to the large number of corrugations, it is difficult for the middle area to effectively obtain the material supplement on both sides, which can easily cause the corrugations in the middle area to be thinned more, or even cracked, resulting in failure to form qualified products. The new process method adopts a step-by-step internal high pressure forming process. For bellows with high corrugation height, large corrugations, and those that are difficult to form in one step, one or several corrugations in the middle are formed by internal high pressure in sequence, such as Figure 2 In this case, since only the middle area has corrugations, it is easier to fill the middle area on both sides, thereby reducing the thinning of the middle area. After the corrugations in the middle area are formed, the corrugations on both sides are formed from the inside to the outside. Figure 3 Ripples 4 and 7 in the figure. Figure 4 This is a simulation diagram of the thinning results of a corrugated tube in one-time forming. The simulation results show that during one-time forming, the maximum thinning of the corrugated tube occurs in the middle area, and the maximum thinning is 24.7%. Figure 5This is a simulation result diagram of thinning of a bellows in step-by-step forming. The simulation results show that when distributed forming is used, the maximum thinning in the middle area of ​​the bellows is only 18.6%. The comparison results show that the distributed forming process can significantly reduce the thinning rate of the corrugation in the middle area, so as to produce qualified products.

[0019] A bellows internal high pressure forming process comprises the following steps:

[0020] (1) Middle area forming: First, high pressure forming is performed on one or more corrugations in the middle, such as Figure 2 The number of corrugations in the figure is 5 and 6. The number of corrugations depends on the formability of the specific part and can be determined by formability simulation analysis software.

[0021] (2) Forming of the two side areas 1: Forming the ripples on both sides from the inside to the outside, such as Figure 3 The number of corrugations in the figure is 4 and 7. The number of formed corrugations depends on the formability of the specific part and can be determined by formability simulation analysis software.

[0022] (3) Forming of the two side areas 2: Based on the simulation analysis results, the remaining corrugations are formed in sequence from the inside to the outside.

[0023] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A bellows internal high pressure forming process, characterized in that: The process steps are: 1) Middle area forming: First, one or several corrugations in the middle are formed by internal high pressure forming. The number of corrugations depends on the formability of the specific part and can be determined by formability simulation analysis software; 2) Forming of the two side areas: The corrugations on both sides are formed successively from the inside to the outside. The number of formed corrugations depends on the formability of the specific parts and can be determined by formability simulation analysis software.

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