Method for manufacturing flange at outlet of shrinkage section of large cryogenic equipment

Abstract

The present application belongs to the technical field of wind tunnel equipment manufacturing, and discloses a manufacturing method of a large low-temperature equipment contraction section outlet flange. The manufacturing method comprises the following steps: preparing a contraction section shell bevel; splitting the outlet flange; assembling the outlet flange; welding the outlet flange; and polishing the weld. The manufacturing method prepares the bevel while cutting the contraction section shell surplus, greatly reducing the cutting deformation; by using different bevel forms at the upper wall, lower wall, left side wall, right side wall and round corner, the problem of difficult preparation of the bevel angle of the contraction section shell outlet end face caused by the change of the included angle between the contraction section shell outlet end face and the outlet flange is solved. By adopting the method of plasma cutting the outlet flange to manufacture the extension curved surface of the inner wall surface of the outlet flange, the smooth transition of the joint surface is achieved by polishing, mechanical processing is avoided, and cost is saved. By installing a deformation prevention support at the outlet of the contraction section shell, the welding deformation is controlled, the contraction section profile precision is improved, and the method has engineering practical value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wind tunnel equipment manufacturing, and particularly relates to a manufacturing method for an outlet flange of a large low-temperature equipment contraction section. BACKGROUND

[0002] The main function of the contraction section is to accelerate the airflow to the required speed, improve the uniformity of the airflow, and reduce the turbulence intensity of the airflow. The inlet of the contraction section is connected with the stable section, and the outlet is connected with the test section. The large low-temperature equipment operates at a temperature close to -196 DEG C. During operation, the structure of the contraction section will have a large contraction deformation. If the longitudinal and annular rib plate + inner thin plate structure is used, there is a risk of cracking of the weld and a risk of deformation of the inner thin plate. Therefore, the contraction section of the large low-temperature equipment is designed as a single-shell structure, and the inner wall of the shell is the inner surface, and the material is austenitic stainless steel.

[0003] The left wall and the right wall of the shell of the contraction section of the large low-temperature equipment are straight curved surfaces and are five-order curves, and the included angle with the outlet flange is small. The upper wall and the lower wall are straight curved surfaces and are double three-order curves, and the included angle with the outlet flange is large. The four round corners are hyperbolic surfaces, and the included angle with the outlet flange is continuously changed. The minimum included angle is equal to the included angle of the left wall and the right wall with the outlet flange, and the maximum included angle is equal to the included angle of the upper wall and the lower wall with the outlet flange. Because the included angle between the shell of the contraction section and the outlet flange is changed, there are three difficulties in the manufacture of the outlet flange: first, the slope angle of the outlet end surface of the shell of the contraction section is difficult to prepare due to the change of the included angle between the outlet end surface of the shell of the contraction section and the outlet flange; second, the inner wall surface of the outlet flange is an extended curved surface of the shell of the contraction section, and the machining cost is high; third, the contraction deformation is large during the welding process of the outlet flange, and the size of the contraction section surface cannot be guaranteed.

[0004] At present, it is urgent to develop a manufacturing method for the outlet flange of the contraction section of the large low-temperature equipment. SUMMARY

[0005] The technical problem to be solved by the application is to provide a manufacturing method for the outlet flange of the contraction section of the large low-temperature equipment, so as to realize the manufacture of the outlet flange of the contraction section of the large low-temperature equipment.

[0006] The manufacturing method for the outlet flange of the contraction section of the large low-temperature equipment comprises the following steps:

[0007] S1. preparing a slope of the shell of the contraction section;

[0008] marking an outlet end surface contour line on the outlet outer wall surface of the shell of the contraction section, cutting along the contour line by using a plasma cutting machine, removing the excess amount, and obtaining the slope of the shell of the contraction section;

[0009] When cutting the upper wall, lower wall, left side wall and right side wall of the contraction section shell, the plasma cutting machine is perpendicular to the outer wall surface of the outlet flange; after cutting, the included angle between the upper wall and lower wall of the contraction section shell and the outlet flange is the bevel angle a, the included angle between the left side wall and right side wall of the contraction section shell and the outlet flange is the bevel angle c, and the included angle between the four round corners of the contraction section shell and the outer wall surface of the outlet flange is (a-c) / 2;

[0010] S2. Disassemble the outlet flange;

[0011] The outlet flange is cut at the end surface of the four round corners into eight segments, including two long axis segments, two short axis segments and four round corner segments;

[0012] The outlet flange is cut along the inner contour using a plasma cutting machine; when cutting the long axis segments, the cutting angle is the bevel angle c; when cutting the short axis segments, the cutting angle is the bevel angle a; and when cutting the round corner segments, the cutting angle is (a+c) / 2;

[0013] S3. Assemble the outlet flange;

[0014] The two long axis segments, two short axis segments and four round corner segments of the outlet flange are assembled on the contraction section shell; a deformation prevention support is installed at the outlet of the contraction section shell;

[0015] S4. Weld the outlet flange;

[0016] Tungsten inert gas welding is used for the backing welding of each segment of the outlet flange and the contraction section shell, and flux-cored wire gas shielded welding is used for the filling and covering welding of the outlet flange and the contraction section shell;

[0017] S5. Welding seam polishing;

[0018] The welding seams at the segments of the contraction section shell and the outlet flange are polished until smooth transition; the contraction section shell is installed in a large low-temperature equipment, and the connection between the contraction section shell and the outlet flange is polished until smooth transition.

[0019] Further, the bevel angle a is greater than 30°, and the bevel angle c is less than 30°.

[0020] Further, when the outlet flange is cut, the inner wall contour is reduced by 4mm-5mm.

[0021] Further, the outlet flange is spot welded on a steel platform before cutting to prevent cutting deformation during cutting.

[0022] Further, the deformation prevention support is composed of a carbon steel pipe and a stainless steel plate, the stainless steel plate is spot welded on the inner wall surface of the contraction section shell, and the carbon steel pipe is welded on the stainless steel plate.

[0023] Further, the outlet flange is welded with the contraction section shell, and the contraction section shell is turned over by 180 DEG before welding, the outlet flange is spot-welded on the steel platform, the welding deformation of the outlet flange is controlled, and the overhead welding is converted into the flat welding.

[0024] Further, the grinding tool is a grinding machine.

[0025] The large low-temperature equipment contraction section outlet flange manufacturing method greatly reduces the cutting deformation by preparing a reasonable contraction section shell bevel preparation scheme and preparing the bevel while cutting the contraction section shell surplus; the problem of difficult preparation of the contraction section shell outlet end surface bevel angle caused by the change of the included angle between the contraction section shell outlet end surface and the outlet flange is solved by adopting different bevel forms at the upper wall, the lower wall, the left side wall, the right side wall and the fillet; the extension curved surface of the outlet flange inner wall surface is manufactured by adopting the plasma cutting outlet flange, the joint surface is polished and smoothly transited, mechanical processing is avoided, and cost is saved; the welding deformation is controlled by installing the anti-deformation support at the outlet of the contraction section shell, and the contraction section profile precision is improved.

[0026] The large low-temperature equipment contraction section outlet flange manufacturing method solves the related problems of the large low-temperature equipment contraction section outlet flange, has high machining precision and has engineering practical value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a contraction section structure schematic diagram of the embodiment;

[0028] Figure 2 It is an outlet flange segmented schematic diagram of the embodiment;

[0029] Figure 3 It is an anti-deformation support installation schematic diagram of the embodiment;

[0030] Figure 4 It is a contraction section shell upper wall, lower wall and outlet flange bevel schematic diagram of the embodiment;

[0031] Figure 5 It is a contraction section shell left side wall, right side wall and outlet flange bevel schematic diagram of the embodiment.

[0032] In the figure, 1 is a contraction section shell, 2 is an outlet flange, 3 is a long axis segment, 4 is a short axis segment, 5 is a fillet segment, and 6 is an anti-deformation support. DETAILED DESCRIPTION

[0033] The application will be described in detail below with reference to the drawings and embodiments.

[0034] Embodiment: The embodiment is aimed at a certain large low-temperature equipment contraction section, and the material of the large low-temperature equipment contraction section is S30403.

[0035] like Figure 1 As shown, the outline of the outlet end face of the contraction section shell 1 is marked on the outer wall surface of the outlet. A plasma cutter is used to cut along the outline, removing excess material to obtain a bevel for the contraction section shell 1. When cutting the upper wall, lower wall, left side wall, and right side wall of the contraction section shell 1, the plasma cutter is perpendicular to the outer wall surface of the outlet. After cutting, as shown... Figure 4 As shown, the angle between the upper and lower walls of the contraction section shell 1 and the outlet flange 2 is the bevel angle α. Figure 5 As shown, the angle between the left and right walls of the contraction section shell 1 and the outlet flange 2 is the bevel angle c; the bevel angle a is greater than 30°, and the bevel angle c is less than 30°; the angle between the four rounded corners of the contraction section shell 1 and the outer wall of the outlet is (ac) / 2.

[0036] like Figure 2 As shown, when cutting the outlet flange 2, the overall inner wall profile is reduced by 5mm. Before cutting, the outlet flange 2 is spot-welded to a steel platform to prevent cutting deformation during the cutting process. During cutting, the outlet flange 2 is broken at the end faces of the four rounded corners, divided into 8 segments, including 2 long axis segments 3, 2 short axis segments 4, and 4 rounded corner segments 5. A plasma cutting machine is used to cut along the inner profile of the outlet flange 2. When cutting the long axis segment 3, the cutting angle is the bevel angle c; when cutting the short axis segment 4, the cutting angle is the bevel angle a; when cutting the rounded corner segment 5, the cutting angle is (a+c) / 2.

[0037] like Figure 3 As shown, the two long shaft segments 3, two short shaft segments 4, and four rounded corner segments 5 of the outlet flange 2 are assembled onto the contraction section shell 1. An anti-deformation support 6 is installed at the outlet of the contraction section shell 1. The anti-deformation support 6 consists of a carbon steel pipe and a stainless steel support plate. The stainless steel support plate is spot-welded to the inner wall of the contraction section shell 1, and the carbon steel pipe is welded to the stainless steel support plate. Before welding the outlet flange 2 to the contraction section shell 1, the contraction section shell 1 can be rotated 180°, and the outlet flange 2 can be spot-welded to the steel platform to control the welding deformation of the outlet flange 2, converting overhead welding to flat welding. The root pass welding of each section of the outlet flange 2 to the contraction section shell 1 is performed using tungsten inert gas welding (TIG). The fill pass welding of the outlet flange 2 to the contraction section shell 1 is performed using flux-cored wire gas shielded welding (FSW). The welds at each section of the contraction section shell 1 and the outlet flange 2 are ground with a grinding wheel until a smooth transition is achieved. The contraction section shell 1 is installed in a large cryogenic equipment, and the connection between the contraction section shell 1 and the outlet flange 2 is ground with a grinding wheel until a smooth transition is achieved.

[0038] While embodiments of the application have been disclosed in connection with the above specification, it will be apparent to those skilled in the art that numerous modifications and variations can be made without departing from the principles of the application. For example, although the application has been described in the context of a particular method, it will be apparent that the application can be implemented in any appropriate type of computer system, or in a computer program product suitable for use in an information handling or processing system. The application is not to be limited to the specific details and examples described above, but is to be controlled by the claims and their equivalents.

Claims

1. A method of manufacturing an outlet flange for a cryogenic plant shrinkage section, characterized in that, The method comprises the following steps: S1. Preparing a bevel of the contraction section shell (1); Marking the contour line of the contraction section outlet end face on the outer wall surface of the contraction section shell (1) outlet, cutting along the contour line with a plasma cutting machine, removing the excess amount, and obtaining the bevel of the contraction section shell (1); When cutting the upper wall, lower wall, left side wall and right side wall of the contraction section shell (1), the plasma cutting machine is perpendicular to the outlet outer wall surface; after cutting, the included angle between the upper wall and lower wall of the contraction section shell (1) and the outlet flange (2) is the bevel angle a, the included angle between the left side wall and right side wall of the contraction section shell (1) and the outlet flange (2) is the bevel angle c, and the included angle between the four round corners of the contraction section shell (1) and the outlet outer wall surface is (a-c) / 2; S2. Splitting the outlet flange (2); The outlet flange (2) is cut at the end face of the four round corners and is divided into eight segments, including two long axis segments (3), two short axis segments (4) and four round corner segments (5); The outlet flange (2) is cut along the inner contour with a plasma cutting machine; when cutting the long axis segment (3), the cutting angle is the bevel angle c; when cutting the short axis segment (4), the cutting angle is the bevel angle a; and when cutting the round corner segment (5), the cutting angle is (a+c) / 2; S3. Assembling the outlet flange (2); The two long axis segments (3), two short axis segments (4) and four round corner segments (5) of the outlet flange (2) are assembled on the contraction section shell (1); and a deformation prevention support (6) is installed at the outlet of the contraction section shell (1); S4. Welding the outlet flange (2); The bottom welding of each segment of the outlet flange (2) and the contraction section shell (1) is performed by adopting tungsten inert gas welding, and the filling and surface welding of the outlet flange (2) and the contraction section shell (1) is performed by adopting flux-cored wire gas shielded welding; S5. Welding seam polishing; The welding seams at the segments of the contraction section shell (1) and the outlet flange (2) are polished until smooth transition; the contraction section shell (1) is installed in a large low-temperature equipment, and then the connection between the contraction section shell (1) and the outlet flange (2) is polished until smooth transition.

2. The method of claim 1, wherein, The bevel angle a is greater than 30°, and the bevel angle c is less than 30°.

3. The method of claim 1, wherein, When the outlet flange (2) is cut, the inner wall contour is reduced by 4mm-5mm as a whole.

4. The method of claim 1, wherein, Before the outlet flange (2) is cut, it is spot-welded on a steel platform to prevent cutting deformation during cutting.

5. The method of claim 1, wherein, The deformation prevention support (6) is composed of a carbon steel pipe and a stainless steel plate, the stainless steel plate is spot-welded on the inner wall surface of the contraction section shell (1), and the carbon steel pipe is welded on the stainless steel plate.

6. The method of manufacturing a cryogenic device shrinkage section exit flange of claim 1, wherein, Before the outlet flange (2) is welded with the contraction section shell (1), the contraction section shell (1) can be turned over by 180°, the outlet flange (2) is spot-welded on a steel platform, the welding deformation of the outlet flange (2) is controlled, and the overhead welding is converted into flat welding.

7. The method of claim 1, wherein, The polishing tool is a grinding machine.

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