A pressure differential barrier structure using laser forming and processing method

Abstract

A pressure differential barrier structure formed by laser forming comprises: a diaphragm (2), an upper retaining ring (3), and a lower retaining ring (1); the upper retaining ring (3) and the lower retaining ring (1) are both annular structures, and together press the edge of the diaphragm (2); the diaphragm (2) is an inverted arch structure, and a cross-shaped weakening groove is processed by laser etching on the inner side of the arch; a sealing groove is provided on the connection surface between the upper retaining ring (3) and the lower retaining ring (1) and the pipeline, and a sealing structure is installed. The present invention has the characteristics of high processing accuracy, product size measurability, high opening pressure accuracy, etc., and can be applied to the pipeline of a rocket power system, and has the characteristics of high yield rate, good product consistency, etc.

Description

Technical Field

[0001] The invention relates to a pressure differential barrier structure and a processing method. Background Art

[0002] The pressure differential barrier structure is mainly used in aerospace, petroleum, chemical industry and other fields. At present, the aerospace field mainly uses pure aluminum material for pressure differential barrier structures, which are generally processed by mechanical punching. The weakening groove is a "V-shaped" structure, and the aluminum diaphragm is warped during the processing, resulting in high difficulty in measuring parameters after molding and poor accuracy; at the same time, it is a pure aluminum material, and the product has poor fatigue resistance, which has a certain impact on engineering applications.

[0003] Pressure differential barrier structures are also widely used in pressure pipelines and containers in the petroleum and chemical industries. However, the requirements for the opening pressure accuracy of barrier structures in the petroleum and chemical industries are relatively low. At the same time, the products are mainly used in ground equipment to facilitate regular maintenance and replacement. Therefore, the pressure differential barrier structures used in the petrochemical industry are mainly mechanically punched. Similarly, there are problems such as low product processing accuracy and poor consistency. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art. The purpose of the present invention is to propose a pressure differential barrier structure and processing method based on laser processing, which has the characteristics of high processing accuracy, product size measurability, high opening pressure accuracy, etc. It can be applied to the pipelines of rocket power systems and has the characteristics of high yield rate and good product consistency.

[0005] The technical solution adopted by the present invention is: a pressure differential barrier structure formed by laser, comprising: a diaphragm, an upper retaining ring, and a lower retaining ring; the upper retaining ring and the lower retaining ring are both annular structures, which jointly press the edge of the diaphragm; the diaphragm is an inverted arch structure, and a cross-shaped weakening groove is processed on the inner side of the arch by laser etching; a sealing groove is set on the connection surface between the upper retaining ring and the lower retaining ring and the pipeline, and a sealing structure is installed.

[0006] The upper retaining ring, the lower retaining ring and the diaphragm are integrated by electron beam welding.

[0007] The upper retaining ring, lower retaining ring and diaphragm are all made of stainless steel 316L material.

[0008] The initial parameters of the diaphragm are calculated by empirical formulas. The initial test parameters include the thickness of the diaphragm, the arch height, and the residual thickness of the notch. The empirical formula is as follows:

[0009] Instability Pressure

[0010] Where, K1 is the material constant, A and B are both empirical parameters, A=21, B=0.304; S0 is the diaphragm thickness, H is the arch height, and d is the arch diameter;

[0011] The diaphragm parameters are further calculated through finite element nonlinear stability analysis, and the material nonlinearity, residual thickness of the notch, and geometric initial defects are used as diaphragm design parameters for finite element analysis. Through multiple rounds of iterations of finite element simulation analysis, the optimal diaphragm design parameters are obtained from the analysis results, and the diaphragm design parameters are used as the final diaphragm size to carry out process tests to verify the pressure differential barrier structure.

[0012] A method for processing a pressure differential barrier structure using laser forming comprises the following steps:

[0013] (1) Calculate the diaphragm parameters;

[0014] (2) selecting diaphragm materials and processing the diaphragm, wherein the diaphragm forming steps include raw material cutting, wire cutting, hydraulic arching, and laser processing of weakened grooves;

[0015] (3) Processing upper and lower retaining rings;

[0016] (4) Weld the upper and lower retaining rings and the diaphragm into a whole.

[0017] The specific method of step (1) is:

[0018] According to the design index requirements, the empirical formula method is used to preliminarily estimate the basic design parameters of the diaphragm, including thickness, arch height, and residual thickness of the notch. The finite element nonlinear stability analysis method is then used to perform simulation analysis iterations. Based on the simulation results, the optimal diaphragm design parameters are selected and process tests are carried out to verify the results.

[0019] In step (2), the diaphragm material is selected from stainless steel.

[0020] In step (2), raw material cutting: the same batch of membranes are required to be taken from the same metal strip, and square metal sheets of certain sizes are cut according to the size specifications;

[0021] Wire cutting: The cut metal material is processed into a circular metal sheet of a set diameter by wire cutting;

[0022] Hydraulic arching: Install the cut circular diaphragm onto the arching tooling, load the arching tooling with the set hydraulic pressure, arch the diaphragm to the designed height, stabilize for 10 minutes, and then remove the arching pressure;

[0023] Laser processing weakening groove: fix the diaphragm on the laser processing equipment, and process the diaphragm with a cross-shaped notch;

[0024] Measurement of residual thickness of notch: Use optical equipment to measure the notch depth, select the workpieces with the largest and smallest depth values, and conduct batch sampling tests for verification.

[0025] In step (3), the upper and lower retaining rings are machined, one side of the surface of the upper and lower retaining rings is a sealing surface, and the other side is in contact with the diaphragm, and the surface roughness of the upper and lower retaining rings is not less than 0.8.

[0026] The specific method of step (4) is:

[0027] The diaphragm and the retaining ring structure are installed in the center on the welding tooling structure, and a certain pre-tightening force is applied axially. After ensuring that the installation is in place, the welding current and welding rate are set, and the structure is welded as a whole.

[0028] The advantages of the present invention compared with the prior art are:

[0029] (1) The use of laser processing to process the weakening groove can achieve precise control of the weakening groove parameters. At the same time, the weakening groove morphology is relatively regular, and the parameters can be measured.

[0030] (2) The product has high processing precision and good product consistency, so the opening pressure performance is more stable and the product reliability is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram of the pressure differential barrier structure;

[0032] Figure 2 It is a three-dimensional model diagram of the pressure differential barrier structure;

[0033] Figure 3 It is the nonlinear stability analysis diagram;

[0034] Figure 4 Create an implementation flow chart for the differential pressure barrier structure. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0036] The material selection requirements for the pressure differential barrier structure include: good laser processing performance, corrosion resistance, good fatigue performance, and good plasticity. Stainless steel 316L material is selected based on comprehensive considerations.

[0037] The pressure differential barrier structure includes: a diaphragm 2, an upper retaining ring 3, and a lower retaining ring 1; the upper retaining ring 3 and the lower retaining ring 1 are both annular structures, which jointly press the edge of the diaphragm 2. The diaphragm 2 is an inverted arch structure, and a cross-shaped weakening groove is processed on the inner side of the arch by laser etching. The structure is destroyed and opened by instability and flipping. During the instability process, the diaphragm 2 is cracked along the weak part, namely the weakening groove. After opening, the diaphragm forms a larger discharge path.

[0038] The upper retaining ring 3, the lower retaining ring 1 and the diaphragm 2 are made of the same material. A sealing groove is set on the connection surface between the upper retaining ring 3 and the lower retaining ring 1 and the pipeline, and a sealing structure is installed. The upper retaining ring 3 and the lower retaining ring 1 and the diaphragm 2 are welded into a whole by electron beam welding, which effectively ensures the sealing of the connection between the diaphragm 2 and the flange. Its structural form is shown in Figure 1 shown.

[0039] Figure 2 It is a three-dimensional model diagram of the pressure differential barrier structure;

[0040] The diaphragm 2 is an inverted arch structure, which relies on structural instability to flip open. The opening pressure is the instability pressure, which is mainly related to the diaphragm parameters such as the thickness of the diaphragm 2, the arch height, and the residual thickness of the notch.

[0041] The initial parameters of diaphragm 2 can be calculated by empirical formula:

[0042] Instability Pressure

[0043] Wherein, K1 is the material constant, A and B are both empirical parameters, generally A=21, B=0.304; S0 is the diaphragm thickness, H is the arch height, and d is the arch diameter.

[0044] This empirical formula does not take into account the influence of notches, and the obtained diaphragm parameters are somewhat different from the actual parameters. Based on this parameter, the diaphragm parameter design is further carried out through finite element nonlinear stability analysis, and the material nonlinearity, notch residual thickness, and geometric initial defects are used as diaphragm design parameters for finite element analysis; through multiple rounds of iterations of finite element simulation analysis, the optimal diaphragm design parameters are obtained from the analysis results, and based on this diaphragm design parameter, the process test verification of the pressure differential barrier structure is carried out.

[0045] The pressure differential barrier structure consists of three components, namely the upper retaining ring, the diaphragm, and the lower retaining ring. The manufacturing process of the structure is shown in Figure 4 Among them, the focus is on the parameter calculation and molding process of the diaphragm. The retaining ring structure is a machined part. There are no special matters and no specific introduction is given.

[0046] (1) Diaphragm parameter calculation

[0047] According to the design index requirements, the basic design parameters of the diaphragm, including thickness, arch height, and residual thickness of the notch, are preliminarily estimated using the empirical formula method. Based on this, the finite element nonlinear stability analysis method is used to carry out simulation analysis iterations. According to the simulation results (such as Figure 3 ), select the optimal diaphragm design parameters, and carry out process test verification.

[0048] (2) Diaphragm processing steps:

[0049] The diaphragm material of the pressure differential barrier structure is made of stainless steel with better elongation, and the diaphragm forming steps include raw material cutting, wire cutting, hydraulic arching, laser processing weakening groove and other steps.

[0050] Raw material cutting: The same batch of diaphragms are required to be taken from the same metal strip and cut into square metal sheets of certain sizes according to the size specifications.

[0051] Wire cutting: The cut metal material is processed into round metal sheets of a certain diameter by wire cutting.

[0052] Hydraulic arching: Install the cut circular diaphragm onto the arching tooling, load a certain amount of hydraulic pressure on the arching tooling to arch the diaphragm to the designed height, stabilize for 10 minutes, and remove the arching pressure after the product state stabilizes.

[0053] Laser processing weakening groove: fix the diaphragm on the laser processing equipment, set the laser processing power, scanning speed, processing route, etc., and carry out notching processing on the diaphragm. The processing notch form is a cross notch.

[0054] Measurement of residual thickness of notch: Use optical equipment to measure the notch depth, select the workpieces with the largest and smallest depth values, and conduct batch sampling tests for verification.

[0055] (3) Processing of upper and lower retaining rings

[0056] The upper and lower retaining rings are machined. One side of the retaining ring surface is the sealing surface, and the other side is in direct contact with the diaphragm. Therefore, there are high requirements for the surface roughness of the retaining ring, and the surface roughness should be guaranteed to be no less than 0.8.

[0057] (4) Overall welding

[0058] The diaphragm and the retaining ring structure are installed in the center on the welding tooling structure, and a certain pre-tightening force is applied axially. After ensuring that the installation is in place, the welding current and welding rate are set, and the structure is welded as a whole.

[0059] After welding is completed, the products are sampled and their performance is tested.

[0060] Parts of the present invention that are not described in detail belong to the well-known technologies of those skilled in the art.

Claims

1. A pressure differential barrier structure formed by laser forming, characterized in that: The invention comprises: a diaphragm (2), an upper retaining ring (3), and a lower retaining ring (1); the upper retaining ring (3) and the lower retaining ring (1) are both annular structures, and together press the edge of the diaphragm (2); the diaphragm (2) is an inverted arch structure, and a cross-shaped weakening groove is processed by laser etching on the inner side of the arch; a sealing groove is provided on the connection surface between the upper retaining ring (3) and the lower retaining ring (1) and the pipeline, and a sealing structure is installed; The upper retaining ring (3), the lower retaining ring (1) and the diaphragm (2) are integrated by electron beam welding; The initial parameters of the diaphragm (2) are calculated by an empirical formula, and the initial test parameters include the thickness of the diaphragm (2), the arch height, and the residual thickness of the notch; the empirical formula is as follows: Instability Pressure In the formula, K1 is the material constant, A and B are both empirical parameters; S0 is the diaphragm thickness, H is the arch height, and d is the arch diameter; The diaphragm parameters are further calculated through finite element nonlinear stability analysis, and the material nonlinearity, notch residual thickness, and geometric initial defects are used as diaphragm design parameters for finite element analysis; Through multiple rounds of iterations of finite element simulation analysis, the optimal diaphragm design parameters are obtained from the analysis results. The diaphragm design parameters are used as the final diaphragm size to carry out process test verification of the pressure differential barrier structure.

2. The pressure differential barrier structure using laser forming according to claim 1, characterized in that: The upper retaining ring (3), the lower retaining ring (1) and the diaphragm (2) are all made of stainless steel 316L material.

3. A method for processing a laser-formed pressure differential barrier structure as described in 1 or 2, characterized in that: The steps include: (1) Calculate the diaphragm parameters; (2) selecting diaphragm materials and processing the diaphragm, wherein the diaphragm forming steps include raw material cutting, wire cutting, hydraulic arching, and laser processing of weakened grooves; (3) Processing upper and lower retaining rings; (4) Weld the upper and lower retaining rings and the diaphragm into a whole.

4. The method for processing a laser-formed pressure differential barrier structure according to claim 3, characterized in that: The specific method of step (1) is: According to the design index requirements, the empirical formula method is used to preliminarily estimate the basic design parameters of the diaphragm, including thickness, arch height, and residual thickness of the notch. The finite element nonlinear stability analysis method is then used to perform simulation analysis iterations. Based on the simulation results, the optimal diaphragm design parameters are selected and process tests are carried out to verify the results.

5. The method for processing a laser-formed pressure differential barrier structure according to claim 4, characterized in that: In step (2), the diaphragm material is selected from stainless steel.

6. The method for processing a laser-formed pressure differential barrier structure according to claim 5, characterized in that: In step (2), raw material cutting: the same batch of membranes are required to be taken from the same metal strip, and square metal sheets of certain sizes are cut according to the size specifications; Wire cutting: The cut metal material is processed into a circular metal sheet of a set diameter by wire cutting; Hydraulic arching: Install the cut circular diaphragm onto the arching tooling, load the arching tooling with the set hydraulic pressure, arch the diaphragm to the designed height, stabilize for 10 minutes, and then remove the arching pressure; Laser processing weakening groove: fix the diaphragm on the laser processing equipment, and process the diaphragm with a cross-shaped notch; Measurement of residual thickness of notch: Use optical equipment to measure the notch depth, select the workpieces with the largest and smallest depth values, and conduct batch sampling tests for verification.

7. The method for processing a laser-formed pressure differential barrier structure according to claim 6, characterized in that: In step (3), the upper and lower retaining rings are machined, one side of the surface of the upper and lower retaining rings is a sealing surface, and the other side is in contact with the diaphragm (2), and the surface roughness of the upper and lower retaining rings is not less than 0.

8.

8. The method for processing a laser-formed pressure differential barrier structure according to claim 7, characterized in that: The specific method of step (4) is: The diaphragm and the retaining ring structure are installed in the center on the welding tooling structure, and a certain pre-tightening force is applied axially. After ensuring that the installation is in place, the welding current and welding rate are set, and the structure is welded as a whole.

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