Efficient manufacturing method for ammonia compressor welding machine shell

Abstract

The invention belongs to the technical field of machine shell preparation, and particularly discloses an efficient preparation method for a welded machine shell of an ammonia compressor, which aims at the welded machine shell of the ammonia compressor with a complex shape, adopts a special welding joint design-vacuum brazing-fillet welding mode to realize one-time welding forming of the welded machine shell of the ammonia compressor, and has the advantages that compared with a conventional welded machine shell, the production efficiency is improved; according to the preparation method provided by the invention, the special-shaped positioning grooves are adopted to realize single-side interlocking of the contact parts of the workpieces, and then the vacuum brazing-vacuum tempering process is adopted, so that the production process of welding the enclosure is simplified, the working intensity of workers is reduced, the production efficiency is improved, and meanwhile, the welding seam quality of the enclosure has higher stability and consistency; and finally, all welding joints are subjected to fillet welding and shot peening strengthening treatment, so that the stability and the surface quality of the welding machine shell are further improved, and a foundation is laid for improving the subsequent productivity and guaranteeing the delivery time of products.

Description

Technical Field

[0001] The invention belongs to the technical field of casing preparation, and in particular relates to a method for efficiently preparing a welded casing of an ammonia compressor. Background Art

[0002] Large compressors are devices that increase gas pressure or transport gas. They are widely used in petrochemical fields such as synthetic ammonia and ethylene. In recent years, with the increase in the company's orders for ammonia compressors, higher requirements have been placed on the production and manufacturing cycle of the units. The casing needs to withstand pressures greater than 50 bar and low temperatures below -40°C during actual operation, so the accuracy and reliability of the casing play a vital role in the performance of the unit. The existing preparation methods for ammonia compressor casings in the industry include precision casting and traditional welding. Due to the complex shape of the casing and the inner cavity size that usually exceeds 1300mm, although precision casting can be used to form an integral part to ensure the strength and reliability of the casing, the casting mold design is difficult, the mold opening cost is high, and defects such as pores, cracks, and shrinkage holes are prone to occur during the casting process, which leads to a low pass rate for the casting casing and a high overall casting cost. The traditional method of welding the casing can reduce the manufacturing cost of the casing by disassembling, assembling, welding and overall processing the casing, and ensure the reliability of the casing through multiple rounds of flaw detection. However, there is a need to reserve a large amount of processing allowance for each welded part, resulting in low material utilization and large material waste. At the same time, due to multiple rounds of flaw detection and overall processing of the casing, the casing manufacturing work intensity is high and the production cycle is long. Summary of the invention

[0003] The purpose of the present invention is to provide an efficient preparation method for an ammonia compressor welded casing, to solve the problems of high labor intensity, low production efficiency and poor welding consistency in traditional welded casing manufacturing, to improve the production efficiency of the ammonia compressor welded casing, and to shorten the product production cycle while ensuring the reliability of the casing.

[0004] In order to achieve the above object, the technical solution of the present invention is: an efficient preparation method of ammonia compressor welded casing, comprising the following steps:

[0005] Casing disassembly: Disassemble the casing according to the casing drawing and divide it into the center flange, bearing seat, shell, sealing plate, partition mounting seat and support plate;

[0006] Cutting: Cutting the split parts;

[0007] Welding joint structure processing: welding joints are processed at the welding positions between the parts; of the two parts to be welded to each other, an arc-shaped positioning groove is processed on one part, and a positioning protrusion matching the positioning groove is processed on the other part; a flaring locking groove is provided on one side of the positioning groove, and a locking block matching the flaring locking groove is provided on one side of the positioning protrusion; a groove is provided on the other side of the positioning protrusion, and the height of the groove is greater than the depth of the positioning groove; an arc-shaped limiting groove is provided at the bottom of the positioning groove, and a limiting block corresponding to the limiting groove is provided at the bottom of the positioning protrusion;

[0008] Pre-cleaning: Clean the processed parts and then dry them;

[0009] Assembly: Assemble the pre-cleaned parts so that the limit block is located in the limit groove and the locking block is located in the expanded locking groove;

[0010] Spot welding: retest and spot weld the assembled casing;

[0011] Adding solder: adding solder into the cavity formed between the groove and the positioning groove;

[0012] Install the auxiliary cover plate: fix the auxiliary cover plate on the outside of the groove, and the auxiliary cover plate is provided with an exhaust hole;

[0013] Vacuum brazing: Place the casing in a vacuum furnace for vacuum brazing;

[0014] Vacuum tempering treatment: The casing is subjected to vacuum tempering treatment and then cooled to room temperature with the furnace;

[0015] Post-processing: After welding is completed, the auxiliary cover plate is removed and the residual flux on the weld and parts is polished;

[0016] Additional corner welding: Additional corner welding is performed on each welding joint of the casing.

[0017] Furthermore, the weight M of the added brazing material is calculated as follows:

[0018] m1=0.8ρdhl

[0019] M=a*m1

[0020] Among them, m1 is the weight of the solder, ρ is the density of the solder, d is the width of the groove, h is the height of the groove, l is the circumference of the positioning groove, and the value of a is 1.0-1.15.

[0021] Furthermore, before the parts are assembled, sodium borate flux needs to be applied to the assembled parts; sodium borate flux is applied to the contact part between the auxiliary cover plate and the solder, and the auxiliary cover plate is made of high-strength graphite plate.

[0022] Further, vacuum brazing: placing the casing in a vacuum furnace for vacuum brazing; specifically: fixing the casing in a vacuum furnace for vacuum positive pressure brazing; the brazing process is divided into the following stages:

[0023] The first stage: the temperature is raised to 200°C, the programming time is 20 to 40 minutes, the pressure is 0.45 mbar under the state of ultimate vacuum;

[0024] The second stage: the temperature is from 200℃ to 210℃, the programming time is 10 to 20 minutes, the pressure is 0.45mbar under the state of extreme vacuum;

[0025] The third stage: the temperature is from 210℃ to 400℃, the programming time is 20 to 40 minutes, the pressure is 0.45mbar under the state of extreme vacuum;

[0026] Stage 4: Temperature from 400°C to 410°C, programming time 10 to 20 minutes, under extreme vacuum, pressure 0.45 mbar;

[0027] Stage 5: Temperature from 410°C to 930-945°C, programming time 50-100 min, under extreme vacuum, pressure 0.45 mbar;

[0028] Stage 6: Maintain the final temperature, programming time 10 to 30 minutes, in the state of ultimate vacuum, the pressure is 0.45 mbar;

[0029] Stage 7: Maintain the final temperature, programming time 10 to 20 minutes, in a low pressure state, the pressure is 1 to 20 bar;

[0030] Stage 8: Maintain the final temperature, programming time 30 to 120 minutes, under high pressure state, pressure is 50 to 100 bar.

[0031] Further, vacuum tempering treatment: vacuum tempering treatment is performed on the casing, and then cooled to room temperature with the furnace. Specifically, when the temperature in the vacuum furnace is lower than 150°C, high-temperature vacuum tempering treatment is performed at a temperature of 430°C to 600°C, and the insulation time is 3 to 6 hours, and then cooled to room temperature with the furnace.

[0032] Furthermore, after the post-processing step, it also includes flaw detection: the casing is flaw detected, and the welds of unqualified positions need to be milled off and manually re-welded until the flaw detection is qualified.

[0033] Furthermore, after the corner welding step, a pressure test is also included: the casing is subjected to a water pressure test and an air pressure test to check the deformation of the casing.

[0034] Furthermore, after the pressure test step, shot peening treatment is also included: first, a shot peening treatment is performed using a Φ3 alloy ball, and then a second shot peening treatment is performed using a Φ1.5 alloy ball.

[0035] Furthermore, the solder is a copper-nickel-manganese-zinc-silicon solder containing 55% Cu, 6% Ni, 4% Mn, 0.15% Si and 34.85% Zn.

[0036] Further, pre-cleaning: the processed parts are cleaned and then dried. Specifically, the processed parts are placed in borax water, heated to 80-100°C, kept warm for 30-60 minutes, and then blown dry with dry compressed air.

[0037] The beneficial effect of the present technical solution is that for the welded casing of the ammonia compressor with complex shape, a special welding joint design - vacuum brazing - fillet welding is adopted to realize the one-time welding and forming of the welded casing of the ammonia compressor. Compared with the conventional welded casing, the preparation method provided by the present invention adopts special-shaped positioning grooves to realize the unilateral interlocking of the contact parts of the workpieces, and then through the vacuum brazing - vacuum tempering process, the production process of the welded casing is simplified, the work intensity of the workers is reduced, and the production efficiency is improved. At the same time, the quality of the casing weld has higher stability and consistency. Finally, by performing fillet welding and shot peening treatment on each welding joint, the stability and surface quality of the welded casing are further improved, which lays a foundation for the subsequent capacity improvement and the guarantee of product delivery time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of a method for efficiently preparing a welded casing of an ammonia compressor according to the present invention;

[0039] Figure 2 It is a structural schematic diagram of the welding joint in the present invention;

[0040] Figure 3 It is a structural schematic diagram of the positioning groove of the present invention;

[0041] Figure 4 A schematic diagram of the structure of the casing. DETAILED DESCRIPTION

[0042] The following is further described in detail through specific implementation methods:

[0043] The figure marks in the drawings of the specification include: shell 1, center flange 2, bearing seat 3, sealing plate 4, partition mounting seat 5, support plate 6, locking block 7, limit block 8, auxiliary cover plate 9, bevel 10, positioning groove 11, expanded locking groove 12, and limit groove 13.

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The embodiment is basically as shown in the attached Figure 1 As shown: An efficient preparation method for ammonia compressor welded casing, comprising the following steps:

[0046] S01: Casing disassembly: Disassemble the casing according to the casing drawing and divide it into the center flange 2, the bearing seat 3, the shell 1, the sealing plate 4, the partition mounting seat 5 and the support plate 6; Figure 4 shown.

[0047] S02: Cutting: Cut the split parts.

[0048] S03: Welding joint structure processing: Welding joints are processed at the welding positions between parts; of the two parts to be welded, one part is processed with an arc-shaped positioning groove 11, and the other part is processed with a positioning protrusion matching the positioning groove; one side of the positioning groove 11 is provided with an expanded locking groove 12, and one side of the positioning protrusion is provided with a locking block 7 matching the expanded locking groove 12; the other side of the positioning protrusion is provided with a groove 10, and the height of the groove 10 is greater than the depth of the positioning groove 11; the bottom of the positioning groove 11 is provided with an arc-shaped limiting groove 13, and the bottom of the positioning protrusion is provided with a limiting block 8 corresponding to the limiting groove 13. Figure 2 , 3 shown.

[0049] S04: Pre-cleaning: Clean the processed parts and then dry them; specifically: put the processed parts into borax water, heat to 80-100℃, keep warm for 30-60min, and then blow dry with dry compressed air.

[0050] S05: Assembly: Apply sodium borate flux to the assembly parts of the pre-cleaned parts, and then assemble the parts according to the overall drawing of the casing, so that the limit block 8 is located in the limit groove 13 and the locking block 7 is located in the expanded locking groove 12.

[0051] S06: Spot welding: Re-test and spot weld the assembled housing to ensure that the dimensions of each internal cavity are consistent with the drawing.

[0052] S07: Add solder: crush the block solder into particles, weigh the solder according to its weight M, and add the solder into the chamber formed between the groove 10 and the positioning groove 11. In this embodiment, the solder is a copper-nickel-manganese-zinc-silicon solder with a content of Cu: 55%, Ni: 6%, Mn: 4%, Si: 0.15%, and Zn: 34.85%. The weight M of the added solder is calculated as follows:

[0053] m1=0.8ρdhl

[0054] M=a*m1

[0055] Among them, m1 is the weight of the solder, ρ is the density of the solder, d is the width of the groove 10, h is the height of the groove 10, l is the circumference of the positioning groove, and the value of a is 1.0-1.15.

[0056] S08: Install the auxiliary cover plate 9: bond the auxiliary cover plate 9 to the outside of the groove 10. The auxiliary cover plate 9 is provided with exhaust holes to facilitate the discharge of gas during brazing. Sodium borate flux is applied to the contact part between the auxiliary cover plate 9 and the solder to increase the fluidity of the solder. The auxiliary cover plate 9 is made of high-strength graphite plate, which can act as a solder resist.

[0057] S09: Vacuum brazing: Fix the casing in a vacuum furnace for vacuum positive pressure brazing; the brazing process is divided into the following stages:

[0058]

[0059] S10: Vacuum tempering treatment: vacuum tempering treatment is performed on the casing, and then the casing is cooled to room temperature with the furnace; specifically, when the temperature in the vacuum furnace is lower than 150°C, high-temperature vacuum tempering treatment is performed at a temperature of 430°C to 600°C, and the heat preservation time is 3 to 6 hours, and then the casing is cooled to room temperature with the furnace. High-temperature vacuum tempering treatment can eliminate the residual stress of brazing.

[0060] S11: Post-processing: After welding is completed, the auxiliary cover plate 9 is removed, and the welding seam and the residual flux on the parts are polished.

[0061] S12: Flaw detection: Carry out magnetic particle inspection on the housing and pass the test of level I according to NB / T47013 standard. The welds of unqualified positions need to be milled off and manually repaired until the flaw detection is qualified.

[0062] S13: Additional corner welding: Additional corner welding is performed on each welding joint of the casing to further improve the stability of the casing.

[0063] S14: Pressure test: subject the casing to a 3.3MPaG water pressure test and a 2.0MPa air pressure test, maintain the pressure for 60 minutes, and then check the deformation of the casing.

[0064] S15: Shot peening treatment: First use Φ3 alloy balls for shot peening, and then use Φ1.5 alloy balls for secondary shot peening. It can increase the surface roughness of the casing.

[0065] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0066] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An efficient preparation method for ammonia compressor welded casing, characterized in that: The following steps are involved: Casing disassembly: Disassemble the casing according to the casing drawing and disassemble it into a center flange (2), a bearing seat (3), a housing (1), a sealing plate (4), a partition mounting seat (5) and a support plate (6); Cutting: Cutting the split parts; Welding joint structure processing: welding joints are processed at welding positions between parts; of two mutually welded parts, one part is processed with an arc-shaped positioning groove (11), and the other part is processed with a positioning protrusion matching the positioning groove (11); one side of the positioning groove (11) is provided with an expanded locking groove (12), and one side of the positioning protrusion is provided with a locking block (7) matching the expanded locking groove (12); the other side of the positioning protrusion is provided with a groove (10), and the height of the groove (10) is greater than the depth of the positioning groove (11); the bottom of the positioning groove (11) is provided with an arc-shaped limiting groove (13), and the bottom of the positioning protrusion is provided with a limiting block (8) corresponding to the limiting groove (13); Pre-cleaning: Clean the processed parts and then dry them; Assembling: Assembling the pre-cleaned parts so that the limiting block (8) is located in the limiting groove (13) and the locking block (7) is located in the expanded locking groove (12); Spot welding: retest and spot weld the assembled casing; Adding solder: adding solder into the cavity formed between the groove (10) and the positioning groove (11); Installing the auxiliary cover plate (9): fixing the auxiliary cover plate (9) on the outside of the groove (10), wherein the auxiliary cover plate (9) is provided with an exhaust hole; Vacuum brazing: Place the casing in a vacuum furnace for vacuum brazing; Vacuum tempering treatment: The casing is subjected to vacuum tempering treatment and then cooled to room temperature with the furnace; Post-processing: After welding is completed, the auxiliary cover plate (9) is removed and the residual flux on the weld and parts is polished; Additional corner welding: Additional corner welding is performed on each welding joint of the casing.

2. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: The weight M of the added solder is calculated as follows: m1=0.8ρdhl M=a*m1 Wherein, m1 is the weight of the solder, ρ is the density of the solder, d is the width of the groove (10), h is the height of the groove (10), l is the circumference of the positioning groove, and the value of a is 1.0-1.

15.

3. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: Before the parts are assembled, sodium borate flux needs to be applied to the assembly site; the sodium borate flux is applied to the contact site between the auxiliary cover plate (9) and the solder, and the auxiliary cover plate (9) is made of high-strength graphite plate.

4. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: Vacuum brazing: Place the casing in a vacuum furnace for vacuum brazing; specifically, fix the casing in a vacuum furnace for vacuum positive pressure brazing; the brazing process is divided into the following stages: The first stage: the temperature is raised to 200°C, the programming time is 20 to 40 minutes, the pressure is 0.45 mbar under the state of ultimate vacuum; The second stage: the temperature is from 200℃ to 210℃, the programming time is 10 to 20 minutes, the pressure is 0.45mbar under the state of extreme vacuum; The third stage: the temperature is from 210℃ to 400℃, the programming time is 20 to 40 minutes, the pressure is 0.45mbar under the state of extreme vacuum; Stage 4: Temperature from 400°C to 410°C, programming time 10 to 20 minutes, under extreme vacuum, pressure 0.45 mbar; Stage 5: Temperature from 410°C to 930-945°C, programming time 50-100 min, under extreme vacuum, pressure 0.45 mbar; Stage 6: Maintain the final temperature, programming time 10 to 30 minutes, in the state of ultimate vacuum, the pressure is 0.45 mbar; Stage 7: Maintain the final temperature, programming time 10 to 20 minutes, in a low pressure state, the pressure is 1 to 20 bar; Stage 8: Maintain the final temperature, programming time 30 to 120 minutes, under high pressure state, pressure is 50 to 100 bar.

5. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: Vacuum tempering treatment: The casing is subjected to vacuum tempering treatment and then cooled to room temperature with the furnace. Specifically, when the temperature in the vacuum furnace is lower than 150°C, high-temperature vacuum tempering treatment is carried out at a temperature of 430°C to 600°C for 3 to 6 hours, and then cooled to room temperature with the furnace.

6. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: After the post-processing steps, it also includes flaw detection: the casing is inspected for flaws, and the welds at unqualified locations need to be milled off and manually re-welded until the flaw detection is qualified.

7. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: After the corner welding step, a pressure test is also included: the casing is subjected to a water pressure test and an air pressure test to check the deformation of the casing.

8. The method for efficiently preparing ammonia compressor welded casing according to claim 7, characterized in that: After the pressure test step, shot peening treatment is also included: first, a Φ3 alloy ball is used for shot peening, and then a Φ1.5 alloy ball is used for secondary shot peening.

9. The method for efficiently preparing ammonia compressor welded casing according to claim 4, characterized in that: The solder is a copper-nickel-manganese-zinc-silicon solder containing 55% Cu, 6% Ni, 4% Mn, 0.15% Si and 34.85% Zn.

10. The method for efficiently preparing ammonia compressor welded casing according to claim 1, characterized in that: Pre-cleaning: Clean the processed parts and then dry them. Specifically, put the processed parts into borax water, heat them to 80-100℃, keep them warm for 30-60 minutes, and then blow them dry with dry compressed air.

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