Boiler steel structure factory modularization manufacturing method

Abstract

The invention discloses a factory modularization manufacturing method for a boiler steel structure, relates to the technical field of boiler steel structure manufacturing, and aims to solve the technical problems that in the prior art, multiple step loopholes exist, management is disordered, and the quality of the boiler steel structure is difficult to guarantee. Carrying out numerical control or gas cutting material cutting; grouping and splicing; welding is conducted; performing correction; installing and welding the stiffened plates; checking and accepting the size; removing rust; paint coating is conducted; and checking and accepting appearance and paint. According to the manufacturing method, all the steps are tightly matched, and the quality of the boiler steel structure is comprehensively guaranteed from strict treatment of steel before blanking, fine control over the environment, materials and the process during welding and quality detection of multiple links such as size acceptance, appearance and paint acceptance, correction after welding and stiffened plate installation and welding. According to the invention, the stability and reliability of the structure are enhanced, and the first-pass yield of products is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of boiler steel structure fabrication technology, and more specifically, to a modular fabrication method for boiler steel structures in a factory. Background Technology

[0002] Modular factory production of boiler steel structures is a modern manufacturing model that breaks down the boiler steel structure fabrication process into multiple modules. These modules are then produced in a standardized, large-scale manner in a factory and transported to the construction site for rapid assembly. This model offers significant advantages. Compared to traditional on-site fabrication, modular factory production is characterized by specialization, scale, and industrialization. Factories have professional personnel and equipment, ensuring manufacturing quality and improving the first-pass yield rate; large-scale production makes full use of resources and reduces costs; and industrialized production makes processes more standardized and automated, facilitating quality control.

[0003] However, in existing technologies, the fabrication of boiler steel structures suffers from quality assurance issues. During the material preparation stage, steel processing is not rigorous enough, potentially resulting in insufficient straightening. After preparation, the edges of the steel are rarely carefully inspected for defects such as delamination, cracks, and slag inclusions, allowing potentially defective steel to enter subsequent fabrication processes. The welding process lacks precise control over the environment, materials, and processes. For example, improper control of humidity and temperature in the welding environment, chaotic management of welding materials, and failure to dry and insulate as required lead to defects such as porosity and cracks in the welds. Furthermore, the quality inspection process is not comprehensive enough, relying solely on visual inspection while neglecting crucial steps such as dimensional verification and internal defect detection. Post-weld correction and standardized installation and welding of stiffening plates to enhance structural stability are also lacking, resulting in a low first-pass yield and an inability to effectively guarantee overall quality. Therefore, we propose a modular fabrication method for boiler steel structures in a factory setting. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology, adapt to practical needs, and provide a modular manufacturing method for boiler steel structures in a factory, so as to solve the technical problems of many loopholes in each step of the current technology, chaotic management, and difficulty in ensuring the quality of boiler steel structures.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a modular manufacturing method for boiler steel structures in a factory, comprising the following steps:

[0006] S1: Drafting and layout;

[0007] S2: CNC or gas cutting for material cutting;

[0008] S3: Group splicing;

[0009] S4: Welding;

[0010] S5: Correction;

[0011] S6: Installation and welding of stiffening plates;

[0012] S7: Dimensional acceptance;

[0013] S8: Rust removal;

[0014] S9: Painting / coating;

[0015] S10: Appearance and paint inspection.

[0016] Preferably, in step S2, the steel is first laid out and assembled, then marked and cut. Before cutting, the steel is straightened. The cutting methods include machining, shearing or punching, band sawing, flame cutting and grinding. After cutting, the edge quality of the steel is ensured, with no delamination, cracks, or slag inclusions. Slag and burrs are removed. For steel of different thicknesses, corresponding stress relief or preheating measures are taken respectively.

[0017] Preferably, the hot-rolled steel splicing in step S3 includes two forms: full penetration butt weld and reinforcing plate structure. When splicing angle steel, channel steel, I-beam and H-beam, different bevel forms and welding methods are adopted according to regulations. Hot-rolled H-beams are purchased in fixed lengths. In special cases of splicing, the web weld holes meet specific size requirements and overlay welding is prohibited. The arrangement of splicing welds complies with regulations. When splicing in the length direction of the components, the number of allowed splicing joints and the shortest splicing length comply with regulations.

[0018] Preferably, gantry welding is used in step S4. The welding process must meet the requirements of the design drawings, process specifications and relevant standards. The welding operation environment must be controlled, including humidity, temperature, surface condition of the weldment and wind protection measures. Welding materials must be managed, dried and kept warm as required, and the welding wire must be cleaned of rust and oil. The preheating temperature must be determined according to various factors and operated correctly. After welding, post-treatment must be carried out as required, including slag removal, hydrogen removal treatment and post-weld heat treatment. Different requirements and treatment methods are applied to welds of different grades.

[0019] Preferably, in step S5, the welded steel structure is corrected to meet the size and shape requirements.

[0020] Preferably, in step S6, stiffening plates are installed and welded at designated locations to enhance the strength and stability of the steel structure.

[0021] Preferably, in step S7, the dimensions of the completed steel structure are measured to ensure that all dimensional deviations meet the specified standards, including the height and width of the composite section, the deviation of the web center, and the deformation requirements of columns and beams, including column bending sag, beam lateral bending sag, and camber.

[0022] Preferably, in step S8, sandblasting is used to treat the surface of the steel structure so that the rust removal grade of the steel surface meets the requirements of the technical documents.

[0023] Preferably, the painting and packaging in step S9 comply with regulations, special requirements are implemented according to relevant technical documents, and certain specific parts are not painted.

[0024] Preferably, in step S10, the appearance and paint quality of the steel structure are inspected to ensure that the welds are free of defects and the paint coating meets the requirements.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The manufacturing method of this invention involves close coordination of each step, from the strict treatment of steel before material preparation, to the meticulous control of the environment, materials, and processes during welding, and to multi-stage quality inspections, such as dimensional acceptance, appearance and paint acceptance, as well as post-weld correction, stiffening plate installation, and welding procedures, comprehensively ensuring the quality of the boiler steel structure. This invention enhances the stability and reliability of the structure and effectively improves the first-pass yield rate.

[0027] 2. This invention employs a modular factory manufacturing method, reducing on-site construction work. Most of the work is completed in the factory, minimizing material waste and rework. Sandblasting for rust removal and standardized painting processes reduce dust and noise pollution during construction. Compared to on-site fabrication, this invention significantly reduces energy consumption and environmental pollution, aligning with green construction principles. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0029] Example 1, such as Figure 1 As shown, the present invention relates to a modular manufacturing method for boiler steel structures in a factory, comprising the following steps:

[0030] S1: Drafting and layout.

[0031] Based on the design drawings, technicians used professional drafting software to create precise drawings and layouts, determining the dimensions, shapes, and positional relationships of each component, providing detailed blueprints for subsequent production.

[0032] After initial drafting and layout are completed using professional drafting software, an internal review by the technical team is required. The review focuses on the accuracy of the dimensions of each component, especially the connections between different modules, where dimensional tolerances must be strictly controlled within allowable limits to ensure the precision of subsequent assembly. Simultaneously, the rationality of the shape design of each component is assessed to avoid shapes that are detrimental to manufacturing or affect structural performance. Regarding positional relationships, the layout of each component within the overall structure is checked to ensure it meets design requirements, especially for critical components affecting overall stability and functionality. The approved drawings must be signed and confirmed by the project manager before they can be used as the basis for subsequent manufacturing processes. Furthermore, if discrepancies are found between the actual situation and the drawings during manufacturing, timely feedback is required. After joint evaluation by the design and technical teams, the drawings are appropriately revised to ensure that manufacturing is always based on accurate drawings.

[0033] S2: CNC or gas cutting for material cutting.

[0034] In step S2, the steel is first laid out and assembled, then marked and cut. Before cutting, the steel is straightened. Cutting methods include machining, shearing or punching, band sawing, flame cutting, and grinding. After cutting, the edge quality of the steel is ensured to be free of delamination, cracks, and slag inclusions. Slag and burrs are removed. For steel of different thicknesses, corresponding stress relief or preheating measures are taken.

[0035] Select qualified Q235B and Q355B steel, and straighten the steel before cutting. Use CNC flame / plasma cutting machine for cutting, and strictly follow the layout dimensions for plate laying, assembly, marking, and cutting. For steel plates thicker than 20mm, perform heat treatment to relieve stress after shearing (punching); for the steel plates of the lower flange of the main beam of the top plate, take measures to eliminate residual stress after flame cutting; when the steel thickness is greater than 40mm and flame cutting is used, preheating is performed according to process requirements.

[0036] When using CNC flame / plasma cutting machines for material cutting, the cutting equipment requires regular calibration and maintenance. Before each use, operators must check the equipment's operating status, including the stability of the flame or plasma jet and the precision of the cutting head, to ensure that the cutting accuracy meets requirements. During the plate laying and assembly process, the flatness of the plates at the splicing points must be checked to ensure that the misalignment at the splicing point does not exceed the specified value, generally controlled within 10% of the thickness of the thinner plate and not exceeding 3mm. In the marking and layout cutting stage, high-precision marking tools should be used, with the marking error controlled within ±1mm to ensure the accuracy of the cutting dimensions. For the inspection of the steel edge quality after cutting, in addition to visual inspection, non-destructive testing methods such as magnetic particle testing or ultrasonic testing should be used for random inspection, with a sampling rate of not less than 10% of the total number of cut materials, to ensure that there are no internal defects on the steel edges. When taking stress relief or preheating measures for steel of different thicknesses, professional temperature measuring equipment should be used to monitor the temperature in real time during the processing to ensure that the processing effect meets the expected standards.

[0037] S3: Group splicing.

[0038] In step S3, the splicing of hot-rolled steel sections includes two forms: full penetration butt welds and reinforcing plate structures. When splicing angle steel, channel steel, I-beams, and H-beams, different bevel forms and welding methods are adopted according to regulations. Hot-rolled H-beams are purchased in fixed lengths. In special cases of splicing, the weld holes in the web must meet specific size requirements, and overlay welding is prohibited. The arrangement of splicing welds must comply with regulations. When splicing in the length direction of components, the number of allowed splicing joints and the shortest splicing length must comply with regulations.

[0039] When splicing hot-rolled steel sections using full-penetration butt welds or reinforced plate structures, the bevel must be ground before welding to remove oxide scale, rust, and other impurities, ensuring weld quality. For reinforced plate structures, the material and specifications of the reinforced plate must strictly meet design requirements. The fit between the reinforced plate and the steel section must be checked to ensure a tight fit with a gap not exceeding 0.5mm. During the splicing of hot-rolled H-beams, if weld holes are involved in the web, after processing, all dimensions of the weld holes must be measured one by one using measuring tools to ensure they meet specific dimensional requirements such as height, edge spacing, and arc-shaped cut radius. After the splicing weld arrangement is completed, the position, length, and angle of the welds must be checked using a weld inspection ruler to ensure compliance with relevant regulations. For splicing along the length of the components, after splicing, the joint must undergo mechanical property testing, including tensile and bending tests, to ensure the strength and toughness of the splicing joint meet design requirements.

[0040] S4: Welding.

[0041] In step S4, gantry welding is used. The welding process must meet the requirements of the design drawings, process specifications and relevant standards. The welding operation environment must be controlled, including humidity, temperature, surface condition of the weldment and wind protection measures. Welding materials must be managed, dried and kept warm as required, and the welding wire must be cleaned of rust and oil. The preheating temperature must be determined based on various factors and operated correctly. After welding, post-treatment must be carried out as required, including slag removal, hydrogen removal treatment and post-weld heat treatment. Different requirements and treatment methods are applied to welds of different grades.

[0042] Ensure relative humidity does not exceed 90%. If the ambient temperature is below 0℃, preheating measures should be taken. If the surface of the weldment is damp, dehumidification treatment should be performed. Select standard-compliant welding materials, such as Atlantic solid core welding wire CHW-50C6, φ1.2mm, etc., and dry and maintain the temperature as required. Determine the preheating temperature based on the steel material, thickness, and environmental conditions, and preheat evenly on both sides of the weld bead. During welding, ensure the surface and edges to be welded are clean. After correctly positioning the weldment, perform tack welding, using the same tack welding material as the final welding material. After welding, remove slag as required, perform hydrogen removal treatment (for structural steels with a high tendency to cold cracking), and undergo post-weld heat treatment.

[0043] During gantry welding, appropriate welding parameters, including welding current, voltage, and welding speed, must be set according to the welding process specifications and monitored in real time to ensure parameter stability. Controlling the welding environment involves routine checks on humidity, temperature, workpiece surface condition, and wind protection measures. Automatic temperature and humidity monitoring equipment should be installed in the welding area to automatically issue alarms and suspend welding operations when environmental parameters exceed permissible ranges. For welding material management, detailed inbound and outbound ledgers should be established, recording information such as material type, specifications, usage, and remaining quantity for traceability and management. During preheating, an infrared thermometer should be used to measure the preheating temperature at multiple points, ensuring uniform distribution within a range of 1.5 times the plate thickness on both sides of the weld bead, and greater than or equal to 100mm. In the post-weld hydrogen removal and heat treatment processes, specialized heat treatment equipment should be used, and operations should be performed according to the specified heating rate, holding time, and cooling rate. A temperature recorder should be used to record temperature changes throughout the process to ensure compliance with process requirements.

[0044] S5: Correction.

[0045] In step S5, the welded steel structure is corrected to meet the size and shape requirements.

[0046] During the calibration process, specialized calibration equipment, such as hydraulic calibration machines and mechanical calibration devices, is employed. Appropriate calibration methods and forces are selected based on the deformation of the steel structure. High-precision measuring instruments, such as laser rangefinders and total stations, are used to measure the dimensions and shape of the steel structure in real time. Calibration parameters are adjusted based on the measurement results to ensure the calibrated steel structure meets dimensional and shape requirements. After calibration, the surface quality of the calibrated areas is inspected to ensure no damage was caused to the steel structure surface during calibration. Any scratches, deformations, or other defects must be repaired promptly. The calibrated steel structure undergoes a second dimensional inspection; only after passing this inspection can the next process begin.

[0047] S6: Installation and welding of stiffening plates.

[0048] In step S6, stiffening plates are installed and welded at designated locations to enhance the strength and stability of the steel structure.

[0049] Before installing stiffening plates, their dimensions and shape must be checked to ensure they meet design requirements. The positioning of the stiffening plates on the steel structure must be accurate; positioning fixtures should be used to ensure the positional deviation does not exceed ±2mm. When welding the stiffening plates, appropriate welding processes and materials should be selected based on the plate's thickness and material. During welding, care must be taken to control welding deformation; segmented welding and symmetrical welding methods can be used. After welding, the weld joints between the stiffening plates and the steel structure should be visually inspected to ensure the weld surface is free of defects such as porosity, cracks, and slag inclusions. A weld gauge should be used to measure the height and width of the weld to ensure it meets design requirements. For stiffening plate weld joints in critical areas, non-destructive testing is required, with a testing rate of no less than 20% of the total number of stiffening plates.

[0050] S7: Dimensional inspection.

[0051] In step S7, the dimensions of the completed steel structure are measured to ensure that all dimensional deviations meet the specified standards, including the height and width of the composite section, the deviation of the web center, and the deformation requirements of columns and beams, including column bending sag, beam lateral bending sag, and camber.

[0052] During dimensional measurement, dimensions such as the height, width, and web center deviation of composite sections must be measured using metrologically verified and calibrated measuring instruments. Measurements must be performed according to prescribed methods and points to ensure data accuracy. For deformation parameters such as column camber, beam lateral camber, and arch, high-precision measuring instruments, such as levels and theodolites, must be used and calibrated before measurement. The influence of the steel structure's self-weight and installation condition on the measurement results must be considered during measurement, and appropriate corrections made to the data. During dimensional acceptance, if dimensional deviations exceed the specified standards, the causes must be analyzed promptly, and corresponding corrective measures, such as correction or rework, must be taken. After rectification, dimensional acceptance must be repeated until the standards are met.

[0053] S8: Rust removal.

[0054] In step S8, sandblasting is used to treat the surface of the steel structure so that the rust removal grade of the steel surface meets the requirements of the technical documents.

[0055] When using sandblasting for rust removal, appropriate sandblasting equipment and abrasives should be selected based on the degree of rust on the steel surface and the requirements of the technical documents. Before sandblasting, the sandblasting equipment should be inspected and tested to ensure normal operation and that parameters such as sandblasting pressure and volume meet the requirements. During sandblasting, the sandblasting angle and distance should be carefully controlled to ensure uniform rust removal from the steel surface without any missed areas. After sandblasting, the surface roughness of the steel should be measured using a roughness measuring instrument to ensure that it meets the roughness requirements corresponding to the rust removal grade specified in the technical documents. Simultaneously, the rust-removed steel surface should be cleaned to remove residual abrasives, dust, and other impurities to avoid affecting the subsequent painting effect.

[0056] S9: Paint coating.

[0057] In step S9, the painting and packaging shall comply with the regulations, and special requirements shall be implemented in accordance with the relevant technical documents. Certain specific parts shall not be painted.

[0058] Before painting, the steel surface should be inspected a second time to ensure it is free of oil, dust, moisture, and other impurities. If any impurities are found, they must be cleaned again. Based on the type of paint and technical document requirements, select appropriate painting equipment, such as spray guns or rollers, and debug the equipment. During the painting process, strictly follow the prescribed painting procedure, controlling parameters such as paint thickness and painting intervals. Generally, the thickness of the primer, intermediate coat, and topcoat should each reach the lower limit of the design requirements, and the total paint thickness must meet the specifications in the technical documents. After painting, protect the painted surface before the paint dries to prevent contamination from dust, debris, etc. For areas with special requirements, such as around high-strength bolt holes and column ends, effective masking should be used during the painting process to avoid paint contamination.

[0059] S10: Appearance and paint inspection.

[0060] In step S10, the appearance and paint quality of the steel structure are inspected to ensure that the welds are free of defects and the paint coating meets the requirements.

[0061] During visual inspection, in addition to checking for defects such as weld beads, burn-through, porosity, and cracks in the welds, the flatness of the steel structure surface must also be checked. A straightedge and feeler gauge should be used for measurement, and the surface flatness deviation should not exceed ±3mm. For the inspection of paint coating quality, besides checking whether the paint coating is uniform and whether there are any missed areas, a paint film thickness gauge should be used to measure the paint thickness at multiple points. The distribution of measurement points should be representative to ensure that the paint thickness meets design requirements. If any problems are found in the appearance or paint quality, they should be repaired promptly, and a new inspection should be conducted after repair. At the same time, the inspection results should be recorded in detail, including the inspection time, personnel, inspection items, and inspection results, to facilitate subsequent quality traceability and management.

[0062] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A modular fabrication method for boiler steel structures in a factory, characterized in that, Includes the following steps: S1: Drafting and layout; S2: CNC or gas cutting for material cutting; S3: Group splicing; S4: Welding; S5: Correction; S6: Installation and welding of stiffening plates; S7: Dimensional acceptance; S8: Rust removal; S9: Painting / coating; S10: Appearance and paint inspection.

2. The modular fabrication method for boiler steel structures according to claim 1, characterized in that, In step S2, the steel is first laid out and assembled, then marked and cut. Before cutting, the steel is straightened. Cutting methods include machining, shearing or punching, band sawing, flame cutting and grinding. After cutting, the edge quality of the steel is ensured, with no delamination, cracks, or slag inclusions. Slag and burrs are removed. For steel of different thicknesses, corresponding stress relief or preheating measures are taken.

3. The modular fabrication method for boiler steel structures according to claim 2, characterized in that, In step S3, the splicing of hot-rolled steel sections includes two forms: full penetration butt welds and reinforcing plate structures. When splicing angle steel, channel steel, I-beams, and H-beams, different bevel forms and welding methods are adopted according to regulations. Hot-rolled H-beams are purchased in fixed lengths. In special cases of splicing, the weld holes in the web must meet specific size requirements, and overlay welding is prohibited. The arrangement of splicing welds must comply with regulations. When splicing in the length direction of components, the number of allowed splicing joints and the shortest splicing length must comply with regulations.

4. A modular fabrication method for boiler steel structures in a factory according to claim 3, characterized in that, In step S4, gantry welding is used. The welding process must meet the requirements of the design drawings, process specifications and relevant standards. The welding operation environment must be controlled, including humidity, temperature, surface condition of the weldment and wind protection measures. Welding materials must be managed, dried and kept warm as required, and the welding wire must be cleaned of rust and oil. The preheating temperature must be determined based on various factors and operated correctly. After welding, post-treatment must be carried out as required, including slag removal, hydrogen removal treatment and post-weld heat treatment. Different requirements and treatment methods are applied to welds of different grades.

5. A modular fabrication method for boiler steel structures in a factory according to claim 4, characterized in that, In step S5, the welded steel structure is corrected to meet the size and shape requirements.

6. A modular fabrication method for boiler steel structures in a factory according to claim 5, characterized in that, In step S6, stiffening plates are installed and welded at designated locations to enhance the strength and stability of the steel structure.

7. A modular fabrication method for boiler steel structures according to claim 6, characterized in that, In step S7, the dimensions of the completed steel structure are measured to ensure that all dimensional deviations meet the specified standards, including the height and width of the composite section, the deviation of the web center, and the deformation requirements of columns and beams, including column bending sag, beam lateral bending sag, and camber.

8. A modular fabrication method for boiler steel structures according to claim 7, characterized in that, In step S8, sandblasting is used to treat the surface of the steel structure so that the rust removal grade of the steel surface meets the requirements of the technical documents.

9. A modular fabrication method for boiler steel structures in a factory according to claim 8, characterized in that, In step S9, the painting and packaging shall comply with the regulations, and special requirements shall be implemented in accordance with the relevant technical documents. Certain specific parts shall not be painted.

10. A modular fabrication method for boiler steel structures according to claim 9, characterized in that, In step S10, the appearance and paint quality of the steel structure are inspected to ensure that the welds are free of defects and the paint coating meets the requirements.

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