Manufacturing method of stainless steel composite stirring shaft supporting frame

Abstract

According to the manufacturing method of the stainless steel composite stirring shaft and the supporting frame, a main shaft is lined with a large-diameter thick-wall carbon steel pipe with the thickness of 904 L of 6-12 mm, a connecting node structure of the main shaft and the supporting frame is reasonably designed, and a set of complete manufacturing and machining technology is adopted; the cost of the chemical reaction tank stirrer can be greatly reduced, meanwhile, the rigidity and the operation stability of a stirring shaft in chemical production are guaranteed, the service life of the whole stirrer is prolonged, and the stirring effect of the chemical reaction tank is improved, and the method comprises the following steps that firstly, a supporting frame is designed, then large-diameter thick-wall carbon steel pipes and stainless steel sleeves are machined, and the supporting frame is blanked and tailor-welded; and machining a paddle mounting end face, assembling and welding the stainless steel composite stirring shaft and the carbon steel pipe, and carrying out airtight test and acceptance. The method is simple, easy to operate, low in cost, resistant to high-temperature strong-acid corrosion and abrasion, capable of guaranteeing the rigidity of the stirring shaft and prolonging the service life and the stirring effect, easy to apply and popularize and good in economic and social benefits, and the stainless steel sleeve is sleeved outside the carbon steel pipe.

Description

Technical Field

[0001] The invention belongs to the field of mechanical processing, and in particular to a method for manufacturing a stainless steel composite stirring shaft support frame. Background Art

[0002] The operation of the agitator in the chemical reaction tank (kettle, tank) plays a key role in material mixing, reaction, dissolution, suspension, dispersion, heat transfer, etc. By mixing the reaction materials through reasonable stirring, the heat and mass transfer of the materials in the tank can be guaranteed, thereby improving the reaction rate and reaction efficiency. However, in chemical reactions, especially in phosphorus chemical and copper, lead and zinc chemical reaction tanks, the stirring is mostly in a high temperature, strong acid, high solid content operating environment, and contains strong corrosive media such as chloride ions and fluoride ions, which can easily cause wear and corrosion to the stirring shaft. Therefore, the chemical agitator tube shaft is mostly made of corrosion-resistant stainless steel such as 2205, 2507, and 904L, and this type of stainless steel is expensive, which increases the production and operation costs.

[0003] In addition, the tank of the chemical agitator is not allowed to be equipped with a bottom bearing for anti-corrosion reasons, and the agitator shaft is mostly a cantilever structure. Therefore, the agitator shaft has high rigidity requirements, and large-diameter thick-walled steel pipes are often used in the design, which increases the production cost. Therefore, how to reduce the cost of chemical reaction agitators while ensuring the rigidity, service life and stirring effect of the agitator shaft is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above situation, in order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for manufacturing a stainless steel composite stirring shaft and a support frame. The main shaft adopts a large-diameter thick-walled carbon steel pipe lining with a thickness of 6-12mm 904L, and the main shaft and the support frame connection node structure are reasonably designed. A complete set of manufacturing and processing technology is adopted, which can greatly reduce the cost of the chemical reaction tank agitator while ensuring the rigidity and operation stability of the agitator shaft in chemical production, extend the service life of the agitator, and improve the stirring effect of the chemical reaction tank; the steps are as follows: (1) First, a support frame is designed. The support frame includes a stainless steel sleeve, a carbon steel pipe and a support frame. The two ends of the carbon steel pipe 1 are tightly covered with stainless steel sleeves 5 connected together symmetrically. The support frame is a frame formed by connecting a transverse support 2 and a longitudinal support 6. The corresponding end of the transverse support 2 is welded to the corresponding end of the stainless steel sleeve 5 and the carbon steel pipe 1 through a welding point 4. The upper and lower ends of the longitudinal support 6 are provided with symmetrical mounting holes 7 for mounting stirring blades. (2) Processing of large-diameter thick-walled carbon steel pipes: Due to the ovality and verticality deviation of carbon steel pipe materials, the outer wall of the carbon steel pipe needs to be processed and the required carbon steel pipe is prepared according to the tolerance requirements of the composite stirring shaft straightness, verticality, surface roughness, etc. (3) Processing of stainless steel casing: Process one end of the stainless steel casing into a 30° groove for easy welding; (4) Support frame cutting: The support frame is a frame composed of a transverse support and a longitudinal support connected together. The corresponding end of the transverse support is welded to the corresponding end of the stainless steel casing and the carbon steel pipe through a welding point. The upper and lower ends of the longitudinal support are provided with symmetrical mounting holes for mounting the stirring blades. Laser cutting is used for cutting; (5) Support frame welding: The support frame is spliced ​​on the platform, welded in multiple layers and multiple passes in sequence, and the welding slag and spatter are removed with a stainless steel wire brush; (6) Processing of the blade installation end face: first process the support frame panel at the connection with the blade bottom plate, then process a 20° single-sided bevel on the panel aperture at the connection with the pipe axis, and process the connection bolt installation holes with the support frame on the blade bottom plate. Drill the bolt holes connecting the blade bottom plate and the support frame; (7) Pipe-shaft assembly: Assemble the stainless steel composite stirring shaft and the carbon steel pipe on the platform, and add plug welding points between the stainless steel pipe and the carbon steel pipe to ensure the fit between the two.

[0005] (8) Welding: The support frame is welded to the carbon steel pipe, and the support frame is welded to the stainless steel casing. The welding process is strictly carried out according to the process card; (9) Airtightness test The airtightness test is strictly carried out in accordance with GB150.1-GB150.4 "Pressure Vessels" and "Safety Technical Inspection Regulations for Stationary Pressure Vessels". When there is a leak, it needs to be retested after repair, pickling and passivation until it is qualified, thereby realizing the production of the stainless steel composite stirring shaft support frame.

[0006] The method of the invention is simple, easy to operate, and low in cost. The carbon steel pipe is covered with a stainless steel casing, which is resistant to high-temperature strong acid corrosion and abrasion, ensures the rigidity of the stirring shaft, prolongs the service life and stirring effect, is easy to promote and apply, and has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a structural diagram of the stainless steel composite stirring shaft support frame of the present invention. DETAILED DESCRIPTION

[0008] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings and specific circumstances.

[0009] Depend on Figure 1 As shown, the manufacturing method of a stainless steel composite stirring shaft support frame of the present invention comprises the following steps: (1) First, a support frame is designed. The support frame includes a stainless steel sleeve, a carbon steel pipe and a support frame. The two ends of the carbon steel pipe 1 are tightly covered with stainless steel sleeves 5 connected together symmetrically. The support frame is a frame formed by connecting a transverse support 2 and a longitudinal support 6. The corresponding end of the transverse support 2 is welded to the corresponding end of the stainless steel sleeve 5 and the carbon steel pipe 1 through a welding point 4. The upper and lower ends of the longitudinal support 6 are provided with symmetrical mounting holes 7 for mounting stirring blades. (2) Processing of large-diameter thick-walled carbon steel pipes: Carbon steel pipe 1 is made of φ508×40 carbon steel pipe material. Due to the deviations in ovality, straightness and roughness of carbon steel pipe materials, the outer circle of the carbon steel pipe needs to be turned for the stainless steel composite stirring shaft. The single-side machining is 1mm, and the carbon steel pipe with a size of φ506×38 is processed. At the same time, the design and manufacturing requirements of roundness ≤0.5mm, straightness ≤5mm / m, and roughness ≤3.2μm are guaranteed; (3) Processing of stainless steel casing: 904L stainless steel is rolled into a matching arc, small holes are drilled on the stainless steel for plug welding, and a stainless steel casing 5 is made, and one end is processed into a 30° groove for easy welding; (4) Support frame cutting: The support frame is a 2507 stainless steel frame composed of a transverse support 2 and a longitudinal support 6. The corresponding end of the transverse support is welded to the corresponding end of the stainless steel sleeve and the carbon steel pipe through solder (welding point). The upper and lower ends of the longitudinal support are provided with symmetrical mounting holes for mounting the stirring blades. Laser cutting is used for cutting. (5) Support frame welding: Place the laser-cut horizontal support 2 and longitudinal support 6 on the platform for splicing, weld in multiple layers and multiple passes in sequence, and use a stainless steel wire brush to remove welding slag and spatter; (6) Processing of the blade installation end face: First, process the support frame panel at the connection with the blade bottom plate, and process the thickness of 0-5mm according to the deviation size. Then, process the panel hole diameter at the connection with the pipe axis to φ508mm, and process a 20° single-side bevel. Then, process the connection bolt installation hole with the support frame on the blade bottom plate, and drill the bolt hole connecting the blade bottom plate and the support frame. (7) Pipe-shaft assembly: Assemble the stainless steel composite stirring shaft and the carbon steel pipe 1 on the platform, cover the carbon steel pipe with a stainless steel sleeve, assemble the support frame and the carbon steel pipe 1, and keep the support frame horizontal and vertical during the assembly process; add plug welding points between the stainless steel pipe and the carbon steel pipe to ensure the fit between the two; (8) Welding: The support frame and the carbon steel pipe 1 are welded with ER2594 welding wire, and the support frame and the stainless steel casing 5 are welded with ER385 welding wire to form welding point 4. The welding process is strictly carried out according to the process card; (9) Airtightness test The airtightness test is strictly carried out in accordance with GB150.1-GB150.4 "Pressure Vessels" and "Safety Technical Inspection Regulations for Stationary Pressure Vessels". When there is a leak, it needs to be retested after repair, pickling and passivation until it is qualified, thereby realizing the production of the stainless steel composite stirring shaft support frame.

[0010] In order to facilitate use and ensure the use effect, the carbon steel pipe 1 is a hollow circle with an outer diameter of ≥426mm and a wall thickness of ≥25mm; The wall thickness of the stainless steel casing 5 is 6-12 mm, and the inner diameter of the stainless steel casing 5 is 0.5-2 mm greater than the outer diameter of the carbon steel pipe 1 .

[0011] The end of the transverse support 2, the inner end of the stainless steel sleeve 5 and the outer wall of the carbon steel pipe 1 form a triangular weld, and the transverse support 2, the stainless steel sleeve 5 and the carbon steel pipe 1 are firmly welded together through the welding point 4; A reinforcing rib plate 9 is installed between the transverse support 2 and the longitudinal support 6 .

[0012] The airtight test is: 1. Each product shall be subjected to air tightness test after passing the overall inspection.

[0013] 2. The safety accessories must be fully assembled and the bolts at all connecting parts must be fully assembled and properly tightened.

[0014] 3. Gas source preparation: The gas used in the test should be dry, clean air, nitrogen, or other inert gases.

[0015] 4. Pressure gauge: Use two pressure gauges with the same range and that have been calibrated and are within the validity period. The pressure gauge range should be 1.5 to 3 times the maximum allowable working pressure, and the pressure gauge accuracy should not be lower than Grade 1.6.

[0016] 5. Installation of pressure gauge: The pressure gauge should be installed on the top of the test container in a position that is easy to observe.

[0017] 6. Pressure test: 1) Air pressure test: First, slowly increase the pressure to 10% of the specified test pressure, maintain the pressure for a sufficient time, and conduct an initial inspection of all welds and joints. If there is no leakage, continue to increase the pressure to 50% of the specified test pressure. If there is no abnormality, then increase the pressure step by step by 10% of the specified test pressure until the test pressure is reached, and maintain the pressure for 30 minutes. Then reduce it to the specified design pressure, maintain the pressure for a sufficient time for inspection.

[0018] 2) Air tightness test: The air tightness test can be carried out on the container only after the pressure test. During the test, the pressure should rise slowly, and the pressure should be maintained for 10 minutes after reaching the specified test pressure. All welding joints and connection parts should be checked for leaks.

[0019] 3) The pressure should remain unchanged during the inspection, and continuous pressurization should not be used to maintain the test pressure constant.

[0020] 4) It is strictly forbidden to tighten the bolts under pressure during the test.

[0021] 8. The air pressure and air tightness test shall be qualified if the following conditions are met: 1) There is no abnormal sound during the test; 2) No visible deformation: 3) Check for leaks using soap solution or other leak detection methods.

[0022] 9. Repair: When there is a leak, retesting is required after repair.

[0023] It can be clearly seen from the above that the method of the present invention is simple and easy to operate. It is an improved processing of the stirring structure of the original agitator, that is, a supporting device is added to the stirring shaft, and the original stirring blades are directly installed on the stirring shaft, and are installed on the supporting device instead, which not only prevents the corrosion of the stainless steel composite stirring shaft by the material, but also strengthens the protection of the stainless steel composite stirring shaft, that is, ensures the stiffness (rigidity) and the service life, and saves materials and reduces costs. Taking the φ508×40mm pipe shaft applied to a 700m³ reaction tank as an example, the pipe shaft length is ~10m. If the whole is made of 904L material, the pipe shaft weight is ~4.6t, and the unit price of 904L pipe per ton is ~100,000 yuan / t. If a carbon steel-lined 6mm stainless steel composite pipe shaft is used, the carbon steel pipe shaft weight is ~4.6t, the 904L stainless steel weight is 0.76t, and the Q355B material unit price per ton is ~4500 yuan / t. A single pipe shaft can save material price ~380,000 yuan, which has good economic and social benefits.

Claims

1. A method for manufacturing a stainless steel composite stirring shaft support frame, characterized in that: Here are the steps: (1) First, a support frame is designed. The support frame includes a stainless steel sleeve, a carbon steel pipe and a support frame. The two ends of the carbon steel pipe (1) are tightly covered with stainless steel sleeves (5) connected together symmetrically. The support frame is a frame formed by connecting a transverse support (2) and a longitudinal support (6). The corresponding end of the transverse support (2) is welded to the corresponding end of the stainless steel sleeve (5) and the carbon steel pipe (1) through a welding point (4). The upper and lower ends of the longitudinal support (6) are provided with symmetrical mounting holes (7) for mounting stirring blades. (2) Processing of large-diameter thick-walled carbon steel pipes: Due to the ovality and verticality deviation of carbon steel pipe materials, the outer wall of the carbon steel pipe needs to be processed and the required carbon steel pipe is prepared according to the tolerance requirements of the composite stirring shaft straightness, verticality, surface roughness, etc. (3) Processing of stainless steel casing: Process one end of the stainless steel casing into a 30° groove for easy welding; (4) Support frame cutting: The support frame is a frame composed of a transverse support and a longitudinal support connected together. The corresponding end of the transverse support is welded to the corresponding end of the stainless steel casing and the carbon steel pipe through a welding point. The upper and lower ends of the longitudinal support are provided with symmetrical mounting holes for mounting the stirring blades. Laser cutting is used for cutting; (5) Support frame welding: The support frame is spliced ​​on the platform, welded in multiple layers and multiple passes in sequence, and the welding slag and spatter are removed with a stainless steel wire brush; (6) Processing of the blade installation end face: first process the support frame panel at the connection with the blade bottom plate, then process a 20° single-sided bevel on the panel aperture at the connection with the pipe axis, and process the connection bolt installation holes with the support frame on the blade bottom plate. Drill the bolt holes connecting the blade bottom plate and the support frame; (7) Pipe-shaft assembly: Assemble the stainless steel composite stirring shaft and the carbon steel pipe on the platform, and add plug welding points between the stainless steel pipe and the carbon steel pipe to ensure the fit between the two; (8) Welding: The support frame is welded to the carbon steel pipe, and the support frame is welded to the stainless steel casing. The welding process is strictly carried out according to the process card; (9) Airtightness test The airtightness test is strictly carried out in accordance with GB150.1-GB150.4 "Pressure Vessels" and "Safety Technical Inspection Regulations for Stationary Pressure Vessels". When there is a leak, it needs to be retested after repair, pickling and passivation until it is qualified, thereby realizing the production of the stainless steel composite stirring shaft support frame.

2. The method for manufacturing a stainless steel composite stirring shaft support frame according to claim 1, characterized in that: Here are the steps: (1) First, a support frame is designed. The support frame includes a stainless steel sleeve, a carbon steel pipe and a support frame. The two ends of the carbon steel pipe (1) are tightly covered with stainless steel sleeves (5) connected together symmetrically. The support frame is a frame formed by connecting a transverse support (2) and a longitudinal support (6). The corresponding end of the transverse support (2) is welded to the corresponding end of the stainless steel sleeve (5) and the carbon steel pipe (1) through a welding point (4). The upper and lower ends of the longitudinal support (6) are provided with symmetrical mounting holes (7) for mounting stirring blades. (2) Processing of large-diameter thick-walled carbon steel pipes: Carbon steel pipe (1) is made of φ508×40 carbon steel pipe material. Due to the deviations in ovality, straightness and roughness of carbon steel pipe materials, the outer circle of the carbon steel pipe needs to be turned for the stainless steel composite stirring shaft. The single-side machining is 1mm, and the carbon steel pipe with a size of φ506×38 is processed. At the same time, the design and manufacturing requirements of roundness ≤0.5mm, straightness ≤5mm / m, and roughness ≤3.2μm are guaranteed; (3) Processing of stainless steel casing: 904L stainless steel is rolled into a matching arc, small holes are drilled on the stainless steel for plug welding, and a stainless steel casing (5) is made, and one end is processed into a 30° groove for easy welding; (4) Support frame cutting: The support frame is a 2507 stainless steel frame composed of a transverse support (2) and a longitudinal support (6) connected together. The corresponding end of the transverse support is welded to the corresponding end of the stainless steel sleeve and the carbon steel pipe by soldering. The upper and lower ends of the longitudinal support are provided with symmetrical mounting holes for mounting the stirring blades. Laser cutting is used for cutting. (5) Support frame welding: Place the laser-cut transverse support (2) and longitudinal support (6) on the platform for splicing, weld in multiple layers and multiple passes, and use a stainless steel wire brush to remove welding slag and spatter; (6) Processing of the blade installation end face: First, process the support frame panel at the connection with the blade bottom plate, and process the thickness of 0-5mm according to the deviation size. Then, process the panel hole diameter at the connection with the pipe axis to φ508mm, and process a 20° single-side bevel. Then, process the connection bolt installation hole with the support frame on the blade bottom plate, and drill the bolt hole connecting the blade bottom plate and the support frame. (7) Pipe-shaft assembly: assemble the stainless steel composite stirring shaft and the carbon steel pipe (1) on the platform, cover the carbon steel pipe with a stainless steel sleeve, assemble the support frame and the carbon steel pipe (1), and keep the support frame horizontal and vertical during the assembly process; add plug welding points between the stainless steel pipe and the carbon steel pipe to ensure the fit between the two; (8) Welding: The support frame and the carbon steel pipe (1) are welded with ER2594 welding wire, and the support frame and the stainless steel casing (5) are welded with ER385 welding wire to form welding points (4). The welding process is strictly carried out according to the process card; then an airtightness test is carried out, and pickling and passivation are carried out until it is qualified, thereby realizing the production of the stainless steel composite stirring shaft support frame.

3. The method for manufacturing a stainless steel composite stirring shaft support frame according to claim 1 or 2, characterized in that: The carbon steel pipe (1) is a hollow circle with an outer diameter of ≥426 mm and a wall thickness of ≥25 mm.

4. The method for manufacturing a stainless steel composite stirring shaft support frame according to claim 1 or 2, characterized in that: The wall thickness of the stainless steel casing (5) is 6-12 mm, and the inner diameter of the stainless steel casing (5) is 0.5-2 mm larger than the outer diameter of the carbon steel pipe (1).

5. The method for manufacturing a stainless steel composite stirring shaft support frame according to claim 1 or 2, characterized in that: A triangular weld is formed between the end of the transverse support (2), the inner end of the stainless steel sleeve (5) and the outer wall of the carbon steel pipe (1), and the transverse support (2), the stainless steel sleeve (5) and the carbon steel pipe (1) are firmly welded together via the welding point (4).

6. The method for manufacturing a stainless steel composite stirring shaft support frame according to claim 1 or 2, characterized in that: A reinforcing rib plate (9) is installed between the transverse support (2) and the longitudinal support (6).

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