Welding process of composite board centrifugal compressor shell

Abstract

The invention relates to a welding process for a composite board centrifugal compressor shell. The welding process is used for solving the technical problems of strength and corrosion resistance of a welding joint. The method comprises the following steps that 1, all parts are pretreated; 2, surfacing treatment is conducted on the upper split flange and the lower split flange; 3, the upper supporting plate and the upper supporting ring are assembled and welded, and an upper supporting plate assembly is formed; the lower supporting plate and the lower supporting ring are assembled and welded to form a lower supporting plate assembly; 4, the upper shell plate and the upper supporting plate assembly are assembled and welded together, and meanwhile the lower shell plate and the lower supporting plate assembly are assembled and welded together; step 5, welding an upper split flange, an upper sealing body, an upper shell plate and an upper side plate together to form an upper shell part; a lower split flange, a lower sealing body, a lower shell plate and a lower side plate are welded together to form a lower shell part; and 6, the upper machine shell part, the lower machine shell part and the air duct are welded and assembled, and welding of the composite board machine shell is completed.

Description

Technical Field

[0001] The invention relates to a casing of a compressor, and in particular to a welding process for a casing of a composite plate centrifugal compressor. Background Art

[0002] Centrifugal compressors are widely used in the fields of petrochemicals, coal chemical industry, acid production, etc. For example, the casing flow path surface of compressors such as circulating gas compressors and nitrogen oxide compressors working under corrosive conditions needs to have corrosion resistance. Such casings are usually cast using stainless steel materials or the casing flow path surface is processed using cladding welding corrosion-resistant materials, which has high manufacturing costs.

[0003] In order to reduce the manufacturing cost of the compressor, the compressor casing is welded and manufactured by combining explosion-proof composite plates made of Q345R and S30408, low-alloy steel plates made of Q345R, and 0Cr19Ni10 materials. In order to ensure the successful welding of this casing, it is necessary to solve the technical problems of poor strength and corrosion resistance of the composite plate welding joints. Summary of the invention

[0004] In order to solve the technical problems of strength and corrosion resistance of composite plate welding joints, the present invention provides a welding process for composite plate centrifugal compressor casing. The strength and corrosion resistance of the joint can be guaranteed by designing a special welding joint form, selecting matching gas shielded welding materials and corrosion-resistant cladding manufacturing process.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A welding process for a composite plate centrifugal compressor casing, which is special in that it includes the following steps:

[0007] Step 1, pre-processing each component;

[0008] Step 2, performing surfacing treatment on the upper center dividing surface flange and the lower center dividing surface flange; after the surfacing treatment is completed, stress relief treatment is performed and the center dividing surface is processed;

[0009] Step 3, assemble and weld the upper support plate and the upper support ring to form an upper support plate assembly; assemble and weld the lower support plate and the lower support ring to form a lower support plate assembly;

[0010] Step 4, assembling and welding the upper shell plate and the upper support plate assembly together, and assembling and welding the lower shell plate and the lower support plate assembly together;

[0011] Step 5, welding the upper center face flange, the upper sealing body, the upper shell plate and the upper side plate together to form an upper casing component;

[0012] Welding the lower center face flange, the lower sealing body, the lower shell plate and the lower side plate together to form a lower shell component;

[0013] Before assembling the upper shell plate and the upper side plate, and the lower shell plate and the lower side plate, a processing step needs to be manufactured to remove the composite metal at the upper end of the upper side plate and the lower end of the lower side plate. The width of the processing step is H = (1.5-2)T, where T is the thickness of the upper shell plate.

[0014] By processing the steps, the base layers between the upper shell plate and the upper side plate, and between the lower shell plate and the lower side plate are welded, and the cladding layers are welded;

[0015] Step 6, welding and assembling the upper casing component, the lower casing component and the air duct to complete the welding and assembly.

[0016] Further, in step 4, before the upper support plate and the upper shell plate and the lower support plate and the lower shell plate are assembled and welded, annular grooves are provided at corresponding welding positions on the inner walls of the upper shell plate and the lower shell plate, so that one side of the upper support plate and the lower support plate is located in the annular grooves;

[0017] K-shaped grooves are arranged at the positions to be welded of the upper support plate and the lower support plate, so that welding between the base layer and the base layer, and between the composite layer and the composite layer can be achieved between the upper support plate and the upper shell plate, and between the lower support plate and the lower shell plate.

[0018] Furthermore, when welding the upper support plate and the upper shell plate and the lower support plate and the lower shell plate, the step width of the processing step is 10 cm, the step angle α=120~150°; the groove angle γ of the K-type groove is 30~45°.

[0019] Furthermore, step 2 is specifically as follows: firstly process the surface to be surfacing of the upper center dividing surface flange and the lower center dividing surface flange, so that the upper center dividing surface flange and the lower center dividing surface flange are thinned to the thickness required for surfacing, and then perform surfacing treatment on the upper center dividing surface flange and the lower center dividing surface flange, so that the upper center dividing surface flange and the lower center dividing surface flange after surfacing treatment reach the thickness before thinning.

[0020] Furthermore, when the base layers are welded, the metal active gas shielded welding process is used for welding, wherein the welding wire grade is H08Mn2SiA and the diameter of the welding wire is The protective gas is a mixture of 80% Ar and 20% CO2.

[0021] Furthermore, when the layers are welded, flux-cored gas shielded welding is adopted, the brand of the welding wire is E308LT1, the diameter of the welding wire is 1.6 mm, and the shielding gas is 99.98% CO2.

[0022] Furthermore, when the composite plate is welded with the S30408 ​​material, the metal inert gas shielded welding process is adopted, the welding wire grade is E309LT1-1, and the diameter of the welding wire is The protective gas is a mixed gas consisting of 98% Ar and 2% O2.

[0023] Furthermore, when the transition layer is welded to the transition layer, flux-cored gas shielded welding is adopted, the welding wire grade is E309LT1, and the diameter of the welding wire is The protective gas is 99.98% CO2.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention solves the technical problem of ensuring the strength of composite plate joints by designing two special joint forms, namely, K-shaped groove and processing step. The composite plate is welded by metal arc welding, which not only ensures the strength of the welded joint, but also satisfies the corrosion resistance of the composite metal. Compared with manual arc welding, the welding efficiency is high and the weld seam is beautiful. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the casing to be welded in the present invention;

[0027] Figure 2 for Figure 1 The enlarged schematic diagram of point I in the middle;

[0028] Figure 3 for Figure 1 Enlarged schematic diagram of point II in the middle.

[0029] The reference numerals are as follows:

[0030] 1. Upper shell plate, 2. Upper side plate, 3. Upper center dividing surface flange, 4. Upper sealing body, 5. Upper supporting ring, 6. Upper supporting plate, 7. Lower shell plate, 8. Lower side plate, 9. Lower center dividing surface flange, 10. Lower sealing body, 11. Lower supporting ring, 12. Lower supporting plate, 13. Air duct, 14. Base layer, 15. Composite layer.

[0031] Specific implementation steps

[0032] The present invention is further described below in conjunction with specific implementations and drawings.

[0033] A welding process for the casing of a composite plate centrifugal compressor, used for welding Figure 1 The centrifugal compressor casing shown in the figure makes the strength of the welded joint and the corrosion resistance of the weld meet the requirements, and the implementation steps are as follows:

[0034] The upper shell plate 1, lower shell plate 7, upper side plate 2, lower side plate 8, upper support plate 6 and lower support plate 12 in the casing are all made of Q345R+S30408 ​​explosion composite plate, that is, the base layer is Q345R material, the composite layer is S30408 ​​material, and a transition layer is arranged between the base layer and the composite layer.

[0035] The upper sealing body 4, the lower sealing body 10, the upper supporting ring 5 and the lower supporting ring 11 are all made of S30408 ​​material.

[0036] Since the materials of the parts are different, it is necessary to ensure that the welding is done between the same materials.

[0037] Before welding, it is necessary to clean the oil and corrosion on the surface of each part and the welding area.

[0038] Step 1: After the corrosion-resistant layer is surfacingly welded on the surface of the upper center face flange 3 and the lower center face flange 9, they are assembled with other parts. The upper center face flange 3 and the lower center face flange 9 are both made of Q345R material.

[0039] Step 2: Welding of parts

[0040] The upper support plate 6 and the upper support ring 5 are welded together to form an upper support plate assembly. Since the outer circle of the upper support plate 6 will contact the inner surface of the upper shell plate 1, direct welding of the two will lead to unstable welding. Therefore, it is necessary to process the upper support plate 6 as follows: Figure 2 K-shaped weld groove shown.

[0041] The lower support plate 12 and the lower support ring 11 are assembled and welded to form a lower support plate assembly, and then a K-shaped welding groove is processed on the lower support plate 12 to allow welding between the same materials.

[0042] Step 3: The upper center face flange 3, the upper sealing body 4, the upper shell plate 1, and the upper side plate 2 are assembled by welding to form an upper casing component.

[0043] The lower center face flange 9, the lower sealing body 10, the lower shell plate 7 and the lower side plate 8 are assembled and welded to form a lower casing component.

[0044] Step 4: The upper casing support assembly is welded to the upper casing assembly in step 3. After the weld is inspected and found to be qualified, heat treatment is performed to eliminate stress.

[0045] Step 5: Weld the lower casing components, lower support plate assembly, air duct and other parts. After the weld inspection is qualified, perform stress relief heat treatment.

[0046] In step 1: before surfacing welding, the upper center dividing surface flange 3 and the lower center dividing surface flange 9 are first processed to be surfacing-welded, so that the upper center dividing surface flange 3 and the lower center dividing surface flange 9 are thinned to the thickness required for surfacing welding, and then surfacing welding is performed on the upper center dividing surface flange 3 and the lower center dividing surface flange 9, so that the thickness of the upper center dividing surface flange 3 and the lower center dividing surface flange 9 after surfacing welding reaches the thickness before thinning. Surfacing welding is performed on the upper center dividing surface flange 3 and the lower center dividing surface flange 9, so that the upper center dividing surface flange 3 and the lower center dividing surface flange 9 have anti-corrosion function. The thickness of the surfacing layer is not less than the composite layer thickness δ+10mm required by the design.

[0047] When the upper support plate 6 and the upper shell plate 1 are welded, an annular groove is machined on the inner surface of the upper shell plate 1 to remove the composite metal. The width of the annular groove is the thickness of the support plate K + (10-20) mm, and the chamfer angle β of the annular groove is 120-150°. When the upper support plate 6 and the upper shell plate 1 are welded, the base layer, transition layer, and composite layer are welded according to the corresponding processes.

[0048] Figure 2 As shown, a K-shaped groove is processed at the position where the upper support plate 6 is connected to the upper shell plate 1, and the groove angle γ is 30-45°, and a step is processed at the interface between the base layer and the composite layer of the upper support plate 6 and the lower support plate 12, and the step width is 10mm, and the step angle α is 120-150°, so that the base layer between the upper support plate 6 and the upper shell plate 1 is welded. This avoids the heat concentration of the base layer and the composite layer section when welding the base metal, causing the composite metal to be delaminated, and also prevents the base metal from being contaminated during welding.

[0049] The welding method of the lower support plate 12 and the lower shell plate 7 is the same as the welding method of the upper shell plate 1 and the upper support plate 6, and both require processing of annular grooves and K-shaped grooves at corresponding positions.

[0050] Before assembling the upper shell plate 1 and the upper side plate 2, and the lower shell plate 7 and the lower side plate 8, Figure 3 As shown, it is necessary to manufacture a processing step in advance to remove the composite metal at the upper end of the upper side plate 2 and the lower end of the lower side plate 8. The width of the processing step is H = (1.5-2)T, T is the thickness of the upper shell plate 1, and the step angle α is 120-150°. The positions where the base layer contacts the base layer are welded in sequence, then the positions where the transition layer is welded to the transition layer, and finally the positions where the composite layer contacts the composite layer. The thickness of the upper shell plate 1 is equal to that of the lower shell plate 7.

[0051] When welding between composite plates, different welding materials are used for the base layer, transition layer and composite metal. The base layer adopts the metal active gas shielded welding (MAG) process, the welding wire brand is: H08Mn2SiA, the welding wire diameter is: Shielding gas: 80% Ar + 20% CO2; welding between transition layers adopts flux-cored gas shielded welding, welding wire brand: E309LT1, welding wire diameter: Gas flow rate: 20-25L / min, wire dry extension: 15-25mm, welding current: 150-280A, shielding gas: 99.98% CO2; flux-cored gas shielded welding is used for welding between layers, wire grade: E308LT1, wire diameter: Gas flow rate: 20-25L / min, wire extension length: 15-25mm, welding current: 150-280A, shielding gas: 99.98% CO2.

[0052] The composite plate is welded with S30408 ​​material using the FCAW process, welding wire grade: E309LT1-1, welding wire diameter: Protective gas: 98% Ar + 2% O2.

[0053] The center surface of the casing (including the center surface flange) is clad. Process method: flux-cored gas shielded welding is used for welding between transition layers. The welding wire brand is E309LT1, and the welding wire diameter is: Gas flow rate: 20-25L / min, wire dry extension: 15-25mm, welding current: 150-280A, shielding gas: 99.98% CO2; flux-cored gas shielded welding is used for welding between layers, welding wire brand:

[0054] E308LT1, wire diameter: Gas flow rate: 20-25L / min, wire dry extension: 15-25mm, welding current: 150-280A, shielding gas: 99.98% CO2, wire composition: C≤0.04, Mn0.5-2.5, Si≤1.0, Cr18.0-21.0, Ni9.0-11.0, Mo≤0.5, CU≤0.5, P≤0.04, S≤0.03.

[0055] The specific steps of the welding process are as follows:

[0056] (1) When welding composite plates, as shown in the enlarged figure II, first weld the base metal, preheat the temperature within 200mm on both sides of the casing welding groove to 10-150℃, control the temperature between welding layers to 300-400℃, and control the welding line energy to within 30KJ / cm; after the base layer is welded, weld the transition layer and composite layer, the interlayer temperature is within 150℃, and the line energy is controlled within 15KJ / cm. The thickness of the transition layer is controlled within 2-3mm;

[0057] (2) When welding the composite plate to the stainless steel S30408 ​​parts, the interlayer temperature is controlled within 150°C and the line energy is controlled within 15KJ / cm. When the welding distance is not less than 8mm from the surface of the parts, an isolation layer is built up inside the groove and on the surface of the Q345 material. After grinding, the filling and cover welding are performed to ensure that the chemical composition of the surface in contact with the medium is uniform.

[0058] (3) When surfacing the center surface, the welding process parameters are the same as those of the composite plate.

Claims

1. A welding process for a composite plate centrifugal compressor casing, characterized in that: The following steps are involved: Step 1, pre-processing each component; Step 2, performing surfacing welding on the upper middle dividing surface flange (3) and the lower middle dividing surface flange (9); After surfacing is completed, stress relief treatment and center surface processing are carried out; Step 3, assembling and welding the upper support plate (6) and the upper support ring (5) to form an upper support plate assembly; assembling and welding the lower support plate (12) and the lower support ring (11) to form a lower support plate assembly; Step 4, assembling and welding the upper shell plate (1) and the upper support plate assembly together, and assembling and welding the lower shell plate (7) and the lower support plate assembly together; Step 5, welding the upper center dividing surface flange (3), the upper sealing body (4), the upper shell plate (1) and the upper side plate (2) together to form an upper casing component; The lower center face flange (9), the lower sealing body (10), the lower shell plate (7) and the lower side plate (8) are welded together to form a lower shell component; Before the upper shell plate (1) and the upper side plate (2) and the lower shell plate (7) and the lower side plate (8) are assembled, a processing step needs to be manufactured to remove the composite metal at the upper end of the upper side plate (2) and the lower end of the lower side plate (8). The width of the processing step is H = (1.5-2)T, where T is the thickness of the upper shell plate (1); By processing the steps, the base layers between the upper shell plate (1) and the upper side plate (2) and between the lower shell plate (7) and the lower side plate (8) are welded to each other, and the composite layers are welded to each other; Step 6, welding and assembling the upper casing component, the lower casing component and the air duct to complete the welding and assembly.

2. A welding process for a composite plate centrifugal compressor casing according to claim 1, characterized in that: In step 4, before the upper support plate (6) and the upper shell plate (1) and the lower support plate (12) and the lower shell plate (7) are assembled and welded, annular grooves are provided at corresponding welding positions on the inner walls of the upper shell plate (1) and the lower shell plate (7), so that one side of the upper support plate (6) and the lower support plate (12) is located in the annular grooves; K-shaped grooves are provided at the positions to be welded of the upper support plate (6) and the lower support plate (12), so that welding between base layers and between composite layers can be achieved between the upper support plate (6) and the upper shell plate (1), and between the lower support plate (12) and the lower shell plate (7).

3. The welding process of a composite plate centrifugal compressor casing according to claim 2, characterized in that: When welding the upper support plate (6) and the upper shell plate (1) and the lower support plate (12) and the lower shell plate (7), the step width of the processing step is 10 cm, the step angle α is 120 to 150°, and the groove angle γ of the K-type groove is 30 to 45°.

4. A welding process for a composite plate centrifugal compressor casing according to claim 2 or 3, characterized in that: Step 2 is specifically as follows: firstly, the surfaces to be clad on the upper center dividing surface flange (3) and the lower center dividing surface flange (9) are processed so as to reduce the thickness of the upper center dividing surface flange (3) and the lower center dividing surface flange (9) required for cladding, and then cladding treatment is performed on the upper center dividing surface flange (3) and the lower center dividing surface flange (9) so that the upper center dividing surface flange (3) and the lower center dividing surface flange (9) after cladding treatment reach the thickness before thinning.

5. The welding process of a composite plate centrifugal compressor casing according to claim 4, characterized in that: When welding the base layers, the metal active gas shielded welding process is adopted, wherein the welding wire brand is H08Mn2SiA, the diameter of the welding wire is φ1.6mm, and the shielding gas is a mixed gas composed of 80% Ar and 20% CO2.

6. The welding process of a composite plate centrifugal compressor casing according to claim 5, characterized in that: When welding the layers, flux-cored gas shielded welding is adopted. The brand of welding wire is E308LT1, the diameter of welding wire is 1.6mm, and the shielding gas is 99.98% CO2.

7. The welding process of a composite plate centrifugal compressor casing according to claim 6, characterized in that: When the composite plate is welded with the S30408 ​​material, the melting inert gas shielded welding process is adopted. The welding wire brand is E309LT1-1, the diameter of the welding wire is φ1.6mm, and the shielding gas is a mixed gas composed of 98% Ar and 2% O2.

8. The welding process of a composite plate centrifugal compressor casing according to claim 7, characterized in that: When the transition layer is welded to the transition layer, flux-cored gas shielded welding is adopted, the welding wire brand is E309LT1, the diameter of the welding wire is φ1.6mm, and the shielding gas is 99.98% CO2.

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