A steel structure box member processing method

Abstract

This invention provides a method for processing steel structure box-type components, belonging to the field of steel structure processing technology. The method includes: pre-processing the steel plate, including cleaning surface impurities and removing rust; leveling the steel plate using specialized leveling equipment to ensure flatness; cutting the steel plate and component plates according to design drawings using CNC cutting equipment; performing secondary leveling on the cut components to eliminate deformation generated during cutting; setting up a jig at the processing site and placing a ground layout line on the jig to provide a reference for subsequent assembly; positioning and placing the bottom panel of the box-type column according to the ground layout line; assembling the internal partitions and web plates sequentially according to design requirements and spot welding for fixation; performing overall welding of the box-type component using submerged arc welding to ensure the integrity and strength of the structure; and performing end milling on the welded box-type component to complete the processing. This method solves the technical problems of existing technologies that hinder the improvement of product quality and production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of steel structure processing technology, and more specifically, relates to a method for processing steel structure box-shaped components. Background Technology

[0002] Steel structures are a widely used structural form in modern architecture, bridges, docks, and other fields, favored for their excellent mechanical properties and relatively light weight. Among them, box-type steel structure components, as a common type of steel structure assembly, play a crucial supporting and load-bearing role in numerous projects. With their closed box-shaped cross-section, high strength, and stiffness, box-type steel structure components are widely used in columns and beams of high-rise buildings, and main beams of long-span bridges. In these projects, box-type components need to withstand large and complex loads such as compression, bending, and shear; therefore, the precision and quality of their manufacturing directly affect the safety performance of the entire steel structure.

[0003] The existing processing technology for box-type steel structure components mainly includes the following steps: First, the steel plates are cleaned and rust-removed. Then, CNC cutting equipment is used to precisely cut the steel plates to obtain the required part dimensions. Next, these parts are assembled into complete box-type components through welding. During the assembly process, temporary support devices (such as jigs) are often required to ensure that the relative positions and dimensions of each part meet the design requirements. Finally, the welded box-type components need to undergo end face machining to meet surface flatness and precision standards.

[0004] Although the aforementioned processing techniques have been widely applied in practice, several problems remain to be solved: First, steel plates are prone to warping and deformation during transportation and storage, which affects the cutting accuracy of subsequent parts; second, the cutting process itself introduces a certain degree of deformation, requiring secondary leveling; third, the relative positions and gaps of each part must be strictly controlled during assembly, placing high demands on the precision of temporary support devices; finally, residual stress and deformation may be introduced during welding, and high precision is also required for end-face processing, all of which increase manufacturing difficulty. In summary, existing box-type component processing techniques present numerous challenges in precision control, hindering improvements in product quality and production efficiency. Summary of the Invention

[0005] In view of this, the present invention provides a method for processing steel structure box-type components, which can solve the technical problems of many precision control difficulties in the existing box-type component processing technology, which are not conducive to improving product quality and production efficiency.

[0006] This invention is implemented as follows:

[0007] The first aspect of the present invention provides a method for processing steel structure box-type components, comprising the following steps:

[0008] S10. Pre-treat the steel plate, including cleaning surface impurities and removing rust;

[0009] S20. Use professional leveling equipment to level the steel plate to ensure flatness;

[0010] S30. According to the design drawings, use CNC cutting equipment to cut the steel plate and parts into blanks;

[0011] S40. Perform secondary straightening on the cut parts to eliminate deformation caused during the cutting process;

[0012] S50. Set up a jig at the processing site and place a ground line on the jig to provide a reference for subsequent assembly;

[0013] S60. Locate and place the bottom panel of the box column according to the ground line;

[0014] S70. Assemble the internal partitions, web plates, and reinforcing structures in sequence according to the design requirements, and fix them by spot welding.

[0015] S80. Use submerged arc welding to weld the box-type components as a whole to ensure the integrity and strength of the structure.

[0016] S90. Perform end milling on the welded box-shaped components to ensure the flatness and precision of the end faces, and complete the processing and manufacturing.

[0017] The reinforcing structure includes reinforcing ribs and corrugated ribs.

[0018] Furthermore, the shape of the internal partition is defined by the following function:

[0019]

[0020] Where W is the width of the box-shaped column, H is the height of the box-shaped column, and 300mm≤W,H≤1500mm are satisfied; A1 and A2 are amplitude parameters; σ is the standard deviation of the Gaussian function, satisfying:

[0021] 0≤A1,A2≤0.05min(W,H), 0.1min(W,H)≤σ≤0.3min(W,H); x represents the coordinate along the width direction of the box column; y represents the coordinate along the height direction of the box column; z represents the coordinate perpendicular to the plane of the box column, that is, the thickness or shape of the box component.

[0022] The shape of the web is defined by the following function:

[0023]

[0024] Where B1, B2, and B3 are shape parameters that satisfy: |B1|, |B2|≤0.02W, |B3|≤0.05W.

[0025] The installation position of the reinforcing rib is defined by the following function:

[0026]

[0027] Where n is the number of reinforcing ribs.

[0028] The installation position and number of the wavy ribs are defined by the following function:

[0029]

[0030] Where m is the number of wavy ribs.

[0031] The shape of the wavy rib is defined by the following function:

[0032]

[0033] Where A is the amplitude, λ is the wavelength, and σ is the amplitude. w Let be the standard deviation of the Gaussian envelope, satisfying: 5mm≤A≤20mm, 50mm≤λ≤200mm, 0.2W≤σ w ≤0.4W.

[0034] The method for determining the number n of reinforcing ribs is as follows:

[0035]

[0036] The method for determining the number m of the wavy ribs is as follows:

[0037]

[0038] Wherein, the thickness t of the steel plate satisfies: 10mm≤t≤50mm;

[0039] The flatness error δ satisfies: δ≤min(0.001L,2mm), where L is the maximum side length of the steel plate;

[0040] The flatness error of the tire frame ∈ satisfies: ∈ ≤ 0.5 mm / m;

[0041] The perpendicularity deviation θ between the bottom panel and the jig satisfies: θ≤0.1°;

[0042] The weld thickness t w Satisfy: t w =min(0.7t,12mm).

[0043] Specifically, step S10 includes: firstly, mechanically cleaning the surface of the steel plate using processes such as shot blasting or sandblasting to remove surface contaminants and oxide layers; then, using acid pickling or alkaline washing methods to dissolve and peel off residual impurities on the steel plate surface with acidic or alkaline solutions, ensuring thorough cleaning and rust removal of the steel plate surface. This combination of mechanical and chemical cleaning methods effectively removes various contaminants and oxides from the steel plate, laying a good foundation for subsequent leveling processes.

[0044] The specific implementation process of step S20 includes: firstly, selecting professional hydraulic leveling machines or CNC horizontal leveling machines, and rationally setting the clamping force and leveling force according to the thickness, width, and material characteristics of the steel plate to ensure that excessive stress is not generated on the steel plate during the leveling process, thus avoiding new deformation. Leveling can be performed in multiple stages, first roughly leveling the steel plate, and then gradually finely adjusting it until the steel plate reaches the designed flatness. This method effectively removes deformation and warping of the steel plate during transportation and storage, ensuring the accuracy of subsequent processing.

[0045] The specific implementation process of step S30 includes: firstly, using a CAD / CAM system to create a cutting program for the steel plate and part plate, and determining the cutting path and parameters according to the requirements of the design drawings; then, using plasma cutting or laser cutting technology to precisely cut the steel plate and part plate. During cutting, the thermal processing properties of the material must be fully considered, and appropriate cutting speed, cutting gap, and cutting gas parameters must be selected to ensure that the dimensional accuracy and surface quality of the cut parts meet the requirements; at the same time, the layout of the parts needs to be rationally arranged to minimize steel plate waste and improve material utilization. Through precise CNC cutting technology, the geometric accuracy of each component required for subsequent assembly can be ensured.

[0046] The specific implementation process of step S40 includes: since cutting will cause a certain degree of deformation on the part, a secondary leveling process is required. A leveling method similar to that in step S20 can be used, first roughly leveling the part to eliminate obvious deformation caused during cutting, and then fine leveling until the surface flatness of the part meets the design requirements. During the leveling process, it is necessary to carefully control the magnitude of the leveling force to avoid excessive stress on the part, which could lead to new deformation. Through this secondary leveling process, it is possible to ensure that the parts can fit precisely during subsequent assembly, improving the overall assembly quality of the box-shaped component.

[0047] The specific implementation process of step S50 includes: First, a stable jig structure needs to be set up at the processing site. The structure and dimensions of the jig should match the dimensions of the box-shaped component in the design drawings to ensure accurate positioning of each part during assembly. On the jig, corresponding ground lines need to be drawn according to the design drawings as a reference for placing the box-shaped bottom panel and other parts. The position and dimensions of the ground lines should be drawn strictly according to the drawing requirements to ensure that the relative positions and gap dimensions of each part meet the design standards. By reasonably setting up the jig and ground lines, a reliable benchmark and reference are provided for the assembly of the box-shaped component.

[0048] The specific implementation process of step S60 includes: placing the bottom panel of the box-shaped component on the jig according to the ground line pre-drawn in step S50, and accurately positioning it according to the ground line. The positioning of the bottom panel requires ensuring that its center line coincides with the ground line, and that all four corner points fall completely within the ground line area. Mechanical positioning pins or laser alignment equipment can be used to assist in positioning, ensuring that the installation position accuracy of the bottom panel meets the requirements. After the bottom panel is in place, it can be initially fixed using welding points or bolts, laying the foundation for the subsequent assembly of other parts. Accurate positioning of the bottom panel ensures that the structural center line and installation position of the entire box-shaped component meet the design requirements.

[0049] The specific implementation process of step S70 includes: according to the requirements of the design drawings, placing the internal partitions and web parts of the box-shaped component sequentially on the bottom panel, and positioning them according to the design dimensions and gaps. Positioning pins or positioning clamps can be used to assist in positioning, ensuring that the installation position and mutual gaps of each part meet the design standards. After positioning, preliminary fixing is performed by spot welding. The weld points should be evenly distributed, and the weld length and depth should meet the strength requirements. After spot welding fixation, the position and angle of the parts can be adjusted appropriately to ensure the geometric accuracy of the overall structure. Through orderly assembly of internal parts, the overall structural dimensions, shape, and assembly quality of the box-shaped component are guaranteed.

[0050] The specific implementation process of step S80 includes: after the assembly of the internal parts is completed, the entire box-shaped component needs to be fully welded using submerged arc welding. Submerged arc welding has advantages such as high heat input, beautiful weld formation, and high weld strength, making it very suitable for welding such large box-shaped components. During the welding process, it is necessary to reasonably select parameters such as welding current, welding voltage, and welding speed to ensure that the weld has sufficient strength and toughness and avoid welding deformation. To further improve the welding quality, a multi-layer welding method can be adopted, first performing root welding, and then performing filler and capping welding layer by layer. Through the overall welding using submerged arc welding, the overall structural stability and load-bearing capacity of the box-shaped component can be ensured.

[0051] The specific implementation process of step S90 includes: after the overall welding is completed, the end face of the box-shaped component needs to be milled to ensure the flatness and accuracy of the end face. A CNC milling machine can be used for end face machining. According to the requirements of the design drawings, parameters such as the milling cutter diameter, feed rate, and rotation speed are adjusted to ensure that excessive vibration and burrs are not generated during the end face machining process. After milling, surface polishing is also required to further improve the smoothness and flatness of the end face. Through precise end face machining, the installation and fit accuracy of the box-shaped component with other structural parts can be ensured, laying the foundation for subsequent overall assembly.

[0052] Compared with existing technologies, the beneficial effects of the steel structure box-type component processing method provided by this invention are:

[0053] First, this invention employs a combination of mechanical and chemical cleaning methods in the steel plate pretreatment stage, effectively removing surface contaminants and oxide layers, laying the foundation for subsequent leveling. Then, specialized hydraulic or CNC leveling equipment is used to precisely level the steel plate, ensuring that the surface flatness meets design requirements before cutting. During CNC cutting, this invention fully considers material properties and cutting process parameters to ensure that part dimensions and surface quality meet standards. To eliminate cutting deformation, a secondary leveling measure is also implemented.

[0054] In the assembly stage, this invention focuses on optimizing the setting of the jig and ground pattern lines, improving the positioning accuracy of the bottom panel. Simultaneously, the shapes of the internal partitions and webs were mathematically modeled and parametrically designed, utilizing complex wave-like and convex shapes to enhance the overall structural rigidity and strength. The distribution and dimensions of the reinforcing ribs and wave-shaped ribs have also been optimized to better meet the stress requirements of different areas. Through these measures, it can be ensured that the relative positions, gap dimensions, and geometric accuracy of all parts of the box-type component fully meet the design standards.

[0055] Finally, in the welding and end-face processing stages, this invention employs advanced processing methods such as submerged arc welding and CNC milling, which not only yields aesthetically pleasing welds and smooth end faces, but also effectively controls welding deformation and residual stress, further improving the overall structural performance of the box-type components.

[0056] Compared with existing technologies, the box-type component processing method proposed in this invention has achieved significant progress in the following aspects: First, by pre-treating the steel plate and performing multiple leveling operations, the flatness of the steel plate before processing is effectively improved, reducing the precision loss during subsequent cutting and assembly processes; second, an innovative internal reinforcing structure with a complex curved surface shape is adopted, which greatly improves the overall rigidity and strength of the box-type component; third, key parameters in the assembly process, such as the flatness of the jig and the positioning of the bottom panel, are optimized to ensure high-precision fit of each part; finally, advanced welding and end-face processing technologies are adopted to effectively control welding deformation and residual stress, further improving the performance of the box-type component.

[0057] In summary, the steel structure box-type component processing method proposed in this invention has made significant progress in improving processing accuracy and quality, and has solved the technical problems of many precision control difficulties in existing box-type component processing technology, which are not conducive to improving product quality and production efficiency. Attached Figure Description

[0058] Figure 1 A flowchart of the method provided by the present invention;

[0059] Figure 2 This is a schematic diagram of the operation process for steps S10-S30; where the left side is the schematic diagram of operation S10, the middle side is the schematic diagram of operation S20, and the right side is the schematic diagram of operation S30.

[0060] Figure 3 This is a schematic diagram of the operation process for steps S40-S60; where the left side is the schematic diagram of operation S40, the middle side is the schematic diagram of operation S50, and the right side is the schematic diagram of operation S60.

[0061] Figure 4 This is a schematic diagram of the operation process in step S70; where the left side is a schematic diagram of the operation of assembling the internal partition, the middle side is a schematic diagram of the operation of assembling the web plate and the reinforcing structure, and the right side is a schematic diagram of the operation of welding.

[0062] Figure 5 This is a schematic diagram of the operation process in step S80; where the left side is a schematic diagram of the operation of assembling the upper panel of the box column, the middle side is a schematic diagram of the operation of overall submerged arc welding, and the right side is a schematic diagram of the operation of turning the component over and performing electroslag welding on the partition plate.

[0063] Figure 6 This is a schematic diagram of the operation process in step S90, where the left side is a schematic diagram of the end milling operation and the right side is a schematic diagram of the completed machining. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0065] like Figure 1 The diagram shown is a flowchart of a steel structure box-type component processing method provided by the present invention. This method includes the following steps:

[0066] S10. Pre-treat the steel plate, including cleaning surface impurities and removing rust;

[0067] S20. Use professional leveling equipment to level the steel plate to ensure flatness;

[0068] S30. According to the design drawings, use CNC cutting equipment to cut the steel plate and parts into blanks;

[0069] S40. Perform secondary straightening on the cut parts to eliminate deformation caused during the cutting process;

[0070] S50. Set up a jig at the processing site and place a ground line on the jig to provide a reference for subsequent assembly;

[0071] S60. Locate and place the bottom panel of the box column according to the ground line;

[0072] S70. Assemble the internal partitions, web plates, and reinforcing structures in sequence according to the design requirements, and fix them by spot welding.

[0073] S80. Use submerged arc welding to weld the box-type components as a whole to ensure the integrity and strength of the structure.

[0074] S90. Perform end milling on the welded box-shaped components to ensure the flatness and precision of the end faces, and complete the processing and manufacturing.

[0075] The specific implementation methods of the above steps are described in detail below:

[0076] Step S10: Pre-treat the steel plate

[0077] The specific implementation of this step includes the following sub-steps:

[0078] First, the steel plate surface needs to be cleaned to remove adhering impurities and rust. This can be achieved through a combination of mechanical and chemical cleaning methods. Mechanical cleaning can employ processes such as shot blasting or sandblasting, using high-speed projectiles of hard particles to impact the steel plate surface, thereby removing surface contaminants and oxide layers. Chemical cleaning can use pickling or alkaline washing methods, utilizing acidic or alkaline solutions to dissolve and peel off the oxide scale and other impurities from the steel plate surface. By combining mechanical and chemical cleaning methods, a thorough cleaning and rust removal of the steel plate surface can be ensured.

[0079] Step S20: Leveling treatment

[0080] The specific implementation of this step includes the following sub-steps:

[0081] First, professional leveling equipment, such as a hydraulic leveler or a CNC horizontal leveler, must be selected. During the leveling process, appropriate clamping and leveling forces must be chosen based on the thickness, width, and material characteristics of the steel plate to ensure that excessive stress is not applied to the steel plate during leveling, thus preventing new deformations. Leveling can be achieved through multiple segmented leveling steps. First, the steel plate is roughly leveled, then gradually fine-tuned until it reaches the designed flatness. This process effectively eliminates deformation and warping that occurs during transportation and storage, ensuring the accuracy of subsequent processing.

[0082] Step S30: CNC cutting and blanking

[0083] The specific implementation of this step includes the following sub-steps:

[0084] First, based on the design drawings, a cutting program for the steel plate and component plates needs to be created using a CAD / CAM system. During the cutting process, the material properties and thickness of the steel plate, as well as the potential thermal deformation during cutting, must be fully considered to select appropriate cutting parameters, such as cutting speed, cutting gap, and cutting gas. Plasma cutting or laser cutting processes are typically used to achieve high cutting accuracy and surface quality. During cutting, attention should also be paid to the reasonable layout of the parts to minimize excess steel material and improve material utilization. Precise CNC cutting processes ensure the dimensional and geometric accuracy of each component required for subsequent assembly.

[0085] Step S40: Secondary leveling

[0086] The specific implementation of this step includes the following sub-steps:

[0087] Because the cutting process causes some deformation to the parts, a secondary leveling process is required. A leveling method similar to step S20 can be used: first, the parts are roughly leveled to eliminate obvious deformation caused during cutting, and then fine leveling is performed until the surface flatness of the parts meets the design requirements. During the leveling process, it is important to control the leveling force to avoid excessive stress on the parts, which could lead to new deformation. This secondary leveling process ensures precise fit between parts during subsequent assembly, improving the overall assembly quality of the box-shaped component.

[0088] Step S50: Carrier positioning

[0089] The specific implementation of this step includes the following sub-steps:

[0090] First, a stable jig structure needs to be set up on the processing site for the subsequent assembly of the box-shaped components. The structure and dimensions of the jig should match the dimensions of the box-shaped components in the design drawings to ensure precise positioning of each part during assembly. On the jig, corresponding ground lines need to be drawn according to the design drawings as a reference for placing the box-shaped bottom panel and other parts. The position and dimensions of the ground lines should be drawn strictly according to the drawing requirements to ensure that the relative positions and gap dimensions of each part meet the design standards. By properly setting up the jig and ground lines, a reliable benchmark and reference are provided for the assembly of the box-shaped components.

[0091] Step S60: Positioning the bottom panel

[0092] The specific implementation of this step includes the following sub-steps:

[0093] Based on the pre-drawn ground line in step S50, place the bottom panel of the box-shaped component on the jig and precisely position it according to the ground line. The positioning of the bottom panel must ensure that its centerline coincides with the ground line, and that all four corner points fall completely within the ground line area. Mechanical locating pins or alignment equipment can be used to assist in positioning, ensuring that the installation position accuracy of the bottom panel meets the requirements. After the bottom panel is in place, it can be initially fixed using welding points or bolts to lay the foundation for the subsequent assembly of other parts. Precise positioning of the bottom panel ensures that the structural centerline and installation position of the entire box-shaped component meet the design requirements.

[0094] Step S70: Internal parts assembly

[0095] The specific implementation of this step includes the following sub-steps:

[0096] According to the design drawings, the internal partitions and web components of the box-shaped structure are placed sequentially on the bottom panel and positioned according to the design dimensions and clearances. Positioning pins or fixtures can be used to assist in positioning, ensuring that the installation position and clearances of each component meet design standards. After positioning, initial fixing is performed using spot welding. The weld points should be evenly distributed, and the weld length and depth should meet strength requirements. After spot welding, the position and angle of the components can be adjusted appropriately to ensure the geometric accuracy of the overall structure. Through orderly assembly of internal components, the overall structural dimensions, shape, and assembly quality of the box-shaped structure are guaranteed.

[0097] Step S80: Overall welding

[0098] The specific implementation of this step includes the following sub-steps:

[0099] After assembling the internal parts, the entire box-shaped component needs to be fully welded using submerged arc welding (SAW). SAW offers advantages such as high heat input, aesthetically pleasing weld formation, and high weld strength, making it highly suitable for welding large box-shaped components. During welding, parameters such as welding current, welding voltage, and welding speed must be carefully selected to ensure sufficient strength and toughness in the weld and prevent welding deformation. To further improve welding quality, a multi-layer welding approach can be employed, starting with root welding followed by layer-by-layer filling and capping welding. Through overall welding using SAW, the overall structural stability and load-bearing capacity of the box-shaped component can be ensured.

[0100] Step S90: End face machining

[0101] The specific implementation of this step includes the following sub-steps:

[0102] After the overall welding is completed, the end faces of the box-shaped components need to be milled to ensure flatness and precision. A CNC milling machine can be used for end face machining. According to the design drawings, parameters such as the milling cutter diameter, feed rate, and spindle speed are adjusted to ensure that excessive vibration and burrs are not generated during the machining process. After milling, surface polishing is required to further improve the smoothness and flatness of the end faces. Precise end face machining ensures the installation and fit accuracy of the box-shaped components with other structural parts, laying the foundation for subsequent overall assembly.

[0103] In summary, the above-mentioned process steps S10 to S90 cover the complete processing flow of steel structure box-type components, including key process links such as pretreatment, leveling, CNC cutting, secondary leveling, jig positioning, bottom panel positioning, internal parts assembly, overall welding, and end face machining. Each step employs corresponding algorithms, process parameter control, and testing methods to ensure that the performance indicators of the box-type components meet the design requirements. Through this series of precise and orderly processing techniques, steel structure box-type components with stable structure, high dimensional accuracy, and good welding quality can be manufactured, laying a solid foundation for subsequent installation and use.

[0104] The following describes the relevant range or shape in detail using formulas: S10. Pre-treat the steel plate, including cleaning surface impurities and removing rust; select a steel plate with a thickness of t, where 10mm≤t≤50mm;

[0105] S20. Use professional leveling equipment to level the steel plate to ensure flatness; the flatness error δ must meet the following condition: δ≤min(0.001L,2mm), where L is the maximum side length of the steel plate;

[0106] S30. According to the design drawings, use CNC cutting equipment to cut the steel plate and parts; the cross-sectional dimensions of the box column are W×H, where W is the width and H is the height, and satisfy 300mm≤W,H≤1500mm;

[0107] S40. Perform secondary leveling on the cut parts to eliminate deformation generated during the cutting process; ensure that the deformation Δ does not exceed 0.002 times the maximum size of the part.

[0108] S50. Set up a jig at the processing site and place a ground line on the jig to provide a reference for subsequent assembly; the flatness error of the jig ∈ satisfies: ∈≤0.5mm / m;

[0109] S60. Locate and place the bottom panel of the box column according to the ground line; the verticality deviation θ between the bottom panel and the jig should satisfy: θ≤0.1°;

[0110] S70. According to the design requirements, assemble the internal partition, web, and reinforcing structure in sequence. The reinforcing structure includes reinforcing ribs and corrugated ribs, and fix them by spot welding. The shapes of the internal partition and web are defined by the following function:

[0111] a) Internal partition shape function:

[0112]

[0113] Where A1 and A2 are amplitude parameters, and σ is the standard deviation of the Gaussian function, satisfying:

[0114] 0≤A1,A2≤0.05min(W,H), 0.1min(W,H)≤σ≤0.3min(W,H)

[0115] b) Web shape function:

[0116]

[0117] Where B1, B2, and B3 are shape parameters, satisfying:

[0118] |B1|, |B2|≤0.02W, |B3|≤0.05W

[0119] c) Function for the installation position of the reinforcing ribs:

[0120]

[0121] Where n is the number of reinforcing ribs, determined by the following formula:

[0122]

[0123] d) The installation location and quantity of the corrugated ribs are determined by a function:

[0124]

[0125] Where m is the number of wavy ribs, determined by the following formula:

[0126]

[0127] e) Shape function of wavy ribs:

[0128]

[0129] Where A is the amplitude, λ is the wavelength, and σ is the amplitude. w Let the standard deviation of the Gaussian envelope satisfy:

[0130] 5mm≤A≤20mm, 50mm≤λ≤200mm, 0.2W≤σ w ≤0.4W

[0131] S80. Submerged arc welding is used to weld the box-type components as a whole, ensuring the integrity and strength of the structure; weld thickness t w Satisfy: t w =min(0.7t,12mm), where t is the thickness of the steel plate;

[0132] S90. Perform end milling on the welded box-shaped components to ensure the flatness and accuracy of the end faces; the end face machining accuracy P must satisfy: P≤0.1mm.

[0133] Declaration of variables and constants:

[0134] t is the steel plate thickness; δ is the steel plate flatness error; L is the maximum side length of the steel plate; W is the width of the box column; H is the height of the box column; Δ is the deformation of the part after cutting; ∈ is the jig flatness error; θ is the perpendicularity deviation between the bottom panel and the jig; A1, A2 are the amplitude parameters of the internal partition shape function; σ is the standard deviation of the Gaussian function in the internal partition shape function; B1, B2, B3 are the shape parameters of the web shape function; n is the number of reinforcing ribs; m is the number of corrugated ribs; A is the amplitude of the corrugated ribs; λ is the wavelength of the corrugated ribs; σ w t represents the standard deviation of the Gaussian envelope in the shape function of the wavy rib; w P represents the weld thickness; P represents the end face machining accuracy.

[0135] Function description:

[0136] 1. Internal partition shape function z(x,y): Combining sine and Gaussian functions, a complex surface with a central bulge and edge undulations is created to enhance structural strength.

[0137] 2. Web shape function y(x): Using a combination of multiple sine and quadratic functions, a complex wave profile is generated to improve bending resistance.

[0138] 3. Reinforcing rib installation position function x i The non-uniform distribution of reinforcing ribs is determined by using a cosine function, and additional support is added in areas of the structure where the stress is high.

[0139] 4. Installation position function y of wavy ribs j Using a sine function to determine the non-uniform distribution of the wavy ribs provides comprehensive structural reinforcement.

[0140] 5. Wave-shaped rib shape function z(x): Combining the sine function and Gaussian envelope, a wave shape with a prominent center and gradual changes at both ends is created to optimize stress distribution.

[0141] These functions take into account the stress conditions of the structure, optimize the structural performance through non-uniform distribution and complex shapes, while maintaining the original processing steps, making the whole scheme more complete and in line with engineering practice.

[0142] To conduct a comprehensive mechanical analysis of the steel box-type structural members and obtain the optimal parameter range, a series of mechanical equations will be established and derived using finite element analysis and multi-objective optimization algorithms. This process will consider various load conditions, material properties, and structural constraints.

[0143] Step 1: Establish stress-strain relationship

[0144] Assuming the material is within its elastic range, the stress-strain relationship is described using the generalized Hooke's law:

[0145] σ ij =CD ijkl ε kl

[0146] Where, σ ij It is the stress tensor, ε kl It is the strain tensor, C ijkl It is the elastic constant tensor. For isotropic materials, it can be simplified to:

[0147]

[0148] Step 2: Establish the equilibrium equation

[0149] To consider the static equilibrium of a box-shaped member, the stress equilibrium equation can be used:

[0150]

[0151] Among them, f x ,f y ,f z It represents volume force.

[0152] Step 3: Consider geometric nonlinearity

[0153] To more accurately describe large deformations, geometric nonlinearity is introduced. The Green-Lagrange strain tensor is used:

[0154]

[0155] Among them, u i It is the displacement component, X i These are the initial configuration coordinates.

[0156] Step 4: Define the shape functions for the internal diaphragms and web.

[0157] Internal partition shape function:

[0158]

[0159] Web shape function:

[0160]

[0161] Step 5: Define the distribution functions for stiffening ribs and corrugated ribs.

[0162] Distribution function of reinforcing ribs:

[0163]

[0164] wavy rib distribution function:

[0165]

[0166] Wavy rib shape function:

[0167]

[0168] Step 6: Establish the finite element model

[0169] The entire structure was discretized using the finite element method. Eight-node hexahedral elements were selected to simulate the main body of the box-shaped component, and four-node shell elements were used to simulate the internal diaphragms, webs, stiffening ribs, and corrugated ribs.

[0170] For a hexahedral element, the shape function can be expressed as:

[0171]

[0172] Where ξ, η, ζ are local coordinate systems.

[0173] For shell elements, degenerate shell theory is adopted, using the Mindlin-Reissner assumption. The displacement field can be expressed as:

[0174] u(x,y,z)=u0(x,y)+zθ y (x,y)

[0175] v(x,y,z)=v0(x,y)-zθ x (x,y)

[0176] w(x,y,z)=w0(x,y)

[0177] Where u0, v0, w0 are mid-surface displacements, and θ x ,θ y It's a corner.

[0178] Step 7: Consider boundary conditions and loads

[0179] Assume the bottom of the box-shaped member is fixed, and the top is subjected to a vertical compressive force p and a horizontal shear force q. The boundary conditions can be expressed as:

[0180] Bottom (z=0): u=v=w=0

[0181] Top (z = H): σ zz =-p,τ zx =q

[0182] At the same time, consider the effect of its own weight: f z =-ρg

[0183] Step 8: Establish the global stiffness matrix and load vector

[0184] After discretization using the finite element method, the global stiffness matrix K and load vector F can be obtained:

[0185] KU = F; where U is the nodal displacement vector.

[0186] Step 9: Consider geometric nonlinearity and material nonlinearity

[0187] To handle geometric nonlinearity, an updated Lagrangian method is employed. At each increment step, the configuration and stress state are updated:

[0188] x i t+Δt =x i t +Δu i

[0189] σ ij t+Δt =σ ij t +Δσ ij

[0190] In this context, the superscripts t and t+Δt represent the current time step and the next time step, respectively.

[0191] For material nonlinearity, the von Mises yield criterion and isotropic hardening model are adopted:

[0192]

[0193] Among them, s ij It is the deviatoric stress tensor, H is the hardening modulus, and ε is the deviatoric stress tens p It is equivalent plastic strain.

[0194] Step 10: Solve the nonlinear equation system

[0195] Solving the nonlinear equation system using the Newton-Raphson iterative method:

[0196] K T ΔU=RF

[0197] Among them, K T R is the tangent stiffness matrix, R is the internal force vector, and F is the external force vector.

[0198] Iterative process:

[0199] 1. Initialize ΔU0 = 0, i = 0

[0200] 2. Calculate the residual ψ i =R(ΔU) i )-F

[0201] 3. If ||ψ i‖<tolerance, end iteration

[0202] 4. Otherwise, solve for K T (ΔU i )δU = -ψ i

[0203] 5. Update ΔU i+1 = ΔU i + δU

[0204] 6. i = i + 1, return to step 2

[0205] Step 11: Calculate stress and strain

[0206] Based on the obtained displacement field, calculate the strain field:

[0207]

[0208] Then use the constitutive equation to calculate the stress field.

[0209] Step 12: Define the objective function

[0210] For multi-objective optimization, define the following objective functions:

[0211] 1. Minimize the structural mass:

[0212] f1 = ρ∫ V dV

[0213] 2. Minimize the maximum von Mises stress:

[0214]

[0215] 3. Minimize the maximum displacement:

[0216]

[0217] 4. Maximize the structural stiffness (minimize the strain energy):

[0218]

[0219] Step 13: Define the constraint conditions

[0220] 1. Geometric constraints:

[0221] 300mm ≤ W, H ≤ 1500mm; 10mm ≤ t ≤ 50mm;

[0222] 2. Parameter constraints:

[0223] 0≤A1,A2≤0.05min(W,H); 0.1min(W,H)≤σ≤0.3min(W,H); |B1|, |B2|≤0.02W; |B3|≤0.05W; 5mm≤A≤20mm; 50mm≤λ≤200mm; 0.2W≤σ w ≤0.4W;

[0224] 3. Strength constraints:

[0225]

[0226] 4. Stability constraints:

[0227] P cr ≥ηP

[0228] Among them, P cr η is the critical buckling load, η is the safety factor, and P is the applied load.

[0229] Step 14: Apply multi-objective optimization algorithm

[0230] The Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was chosen to solve this multi-objective optimization problem. The main steps of NSGA-II are as follows:

[0231] 1. Initialize the population P0 with a size of N.

[0232] 2. Perform non-dominated sorting and crowding calculation on P0.

[0233] 3. For each generation t = 1, 2, ..., T:

[0234] a. Generate offspring Q using binary tournament selection, crossover, and mutation operations. t

[0235] b. Merge parent and child generations: R t =P t ∪Q t

[0236] c. Regarding R t Perform a non-dominated sort to obtain the non-dominated fronts F1, F2, ...

[0237] d. Generate a new population P t+1 :

[0238] -If |F1|+|F2|+...+|F i If |≤N, then all these frontiers are added to P. t+1

[0239] -For the last frontier F that can be partially joined j Select individuals based on their crowding level.

[0240] e. If the termination condition is met, end; otherwise, return to step a.

[0241] Step 15: Pareto optimal solution set analysis

[0242] The following analysis is required for the obtained Pareto optimal solution set:

[0243] 1. Calculate the objective function value and constraint satisfaction for each solution.

[0244] 2. Plot a scatter plot matrix of the objective function to observe the trade-offs between the objectives.

[0245] 3. Calculate the hypervolume indicator to evaluate the quality and diversity of the solution set.

[0246] 4. Use parallel coordinate plots to visualize high-dimensional Pareto fronts

[0247] A Pareto optimal solution set is a set of solutions to a multi-objective optimization problem, in which no single solution is superior to all others in all objectives. In the optimization problem of steel structure box-girder components, the Pareto optimal solution set contains a series of different design schemes, each performing well on some objectives and slightly worse on others. Specifically, each solution in the Pareto optimal solution set includes the following parameters:

[0248] 1. Geometric parameters: W: width of box column; H: height of box column; L: length of box column; t: thickness of steel plate;

[0249] 2. Internal partition shape parameters: A1: First amplitude parameter; A2: Second amplitude parameter; σ: Standard deviation of Gaussian function;

[0250] 3. Web shape parameters: B1: First sine function coefficient; B2: Second sine function coefficient; B3: Quadratic function coefficient;

[0251] 4. Strengthening structural parameters: n: number of reinforcing ribs; m: number of corrugated ribs; A: amplitude of corrugated ribs; λ: wavelength of corrugated ribs; σ w : Standard deviation of Gaussian envelope of wavy ribs;

[0252] Each Pareto optimal solution contains the specific values ​​of these parameters, as well as the corresponding objective function value:

[0253] 1.f1: Structural mass

[0254] 2.f2: Maximum von Mises stress

[0255] 3.f3: Maximum displacement

[0256] 4.f4: Structural stiffness (reciprocal of strain energy)

[0257] Optional, Step 16: Sensitivity Analysis

[0258] To understand the impact of parameters on the objective function, a global sensitivity analysis is performed:

[0259] 1. Calculate the first-order and total effect sensitivity indices using the Sobol method. The Sobol method is based on variance decomposition and can quantify the contribution of each input parameter to the output variance.

[0260] For each objective function f k Calculate the first-order sensitivity index S i And the overall effect sensitivity index S Ti :

[0261]

[0262] Where, x i It is the i-th input parameter, x -i Indicates division by x i All other parameters except those mentioned above.

[0263] 2. Use the Morris method to screen and identify important and unimportant parameters. The Morris method calculates the basic effect of each parameter:

[0264]

[0265] Then calculate the mean μ of the basic effect. i and standard deviation σ i .

[0266] Optional, Step 17: Consider uncertainty

[0267] To account for the uncertainties in parameters and loads, a probabilistic model is introduced:

[0268] 1. Assume material properties (such as elastic modulus E, yield strength σ) y It follows a normal distribution:

[0269]

[0270] 2. Assume that the geometric parameters (such as thickness t) follow a log-normal distribution:

[0271]

[0272] 3. Assume the loads (such as pressure p and shear q) follow an extreme value distribution:

[0273] p~Gumbel(μ p ,β p)

[0274] q~Gumbel(μ q ,β q )

[0275] Optional, Step 18: Reliability Analysis

[0276] Based on the above uncertainty model, a reliability analysis is conducted:

[0277] 1. Define the limit state function:

[0278] g1(X)=σ y -σ eq (X) (Strength Failure)

[0279] g2(X)=u allow -u max (X) (Excessive deformation)

[0280] g3(X)=P cr (X)-ηP (buckling failure)

[0281] Where X is a vector of random variables, containing material properties, geometric parameters, and loads.

[0282] 2. Calculate the failure probability:

[0283] The first-order reliability method (FORM) is used to estimate the probability of failure. The main steps of FORM include:

[0284] a. Convert all random variables to the standard normal space.

[0285] b. Locate the failure point (design point) closest to the origin in the standard normal distribution space.

[0286] c. Calculate the reliability index β = ||u * ‖, where u * Design point coordinates

[0287] d. Calculate the failure probability P f =Φ(-β), where Φ is the standard normal cumulative distribution function.

[0288] 3. Calculate the sensitivity coefficient:

[0289]

[0290] Where, α i This indicates the degree of influence of the i-th standardized random variable on the reliability index.

[0291] Optional, Step 19: Fatigue Analysis

[0292] Consider the fatigue behavior of box-shaped components under cyclic loading:

[0293] 1. Use the rainflow counting method to process the stress-time history and obtain stress cycle counts.

[0294] 2. Calculate the damage for each stress cycle based on the material's SN curve:

[0295]

[0296] Where, n i N is the actual number of cycles for a specific stress amplitude. i It is the number of cycles that lead to fatigue failure.

[0297] 3. Calculate the total damage using Miner's linear cumulative damage theory:

[0298] D = ∑ i D i

[0299] 4. Define the limit state function for fatigue failure:

[0300] g4(X) = 1 - D(X)

[0301] Optional, step 20: Consider the impact of welding

[0302] Welding can affect material properties and introduce residual stress; these factors need to be considered:

[0303] 1. Define the extent of the heat-affected zone (HAZ) and the changes in material properties. Assume the HAZ width is w. HAZ The material strength decreases in this region:

[0304] σ y,HAZ =k HAZ σ y

[0305] Where, k HAZ It is the strength reduction factor, which is usually less than 1.

[0306] 2. Introduce the welding residual stress field σ rs (x,y,z). The residual stress distribution can be predicted using analytical models or finite element simulations.

[0307] 3. Modify the stress state, taking into account the influence of residual stress:

[0308] σ total =σ applied +σ rs

[0309] 4. Consider the effects of welding in fatigue analysis and modify the SN curve:

[0310] log N = log am log(Δσ·k) f )

[0311] Where, k f It is the coefficient for reducing welding fatigue strength.

[0312] Optional, step 21: Consider the effects of corrosion

[0313] Assuming the box-type structural member is used in a corrosive environment, the impact of corrosion on structural performance needs to be considered:

[0314] 1. Establish a corrosion rate model. Assume the corrosion rate is r. c The relationship with time t is:

[0315] r c (t)=k c t n

[0316] Where, k c and n are parameters related to the environment and materials.

[0317] 2. Calculate the thickness as it changes over time:

[0318]

[0319] Where t0 is the initial thickness and T is the service time.

[0320] 3. Update the structural analysis model and replace the original thickness with t(T).

[0321] 4. Define the limit state function for corrosion failure:

[0322]

[0323] Among them, t min It is the minimum allowable thickness.

[0324] Optional, step 22: Consider the effect of temperature

[0325] Assuming the box-shaped component operates in a varying temperature environment, the effects of temperature on material properties and structural response need to be considered:

[0326] 1. Establish a temperature field model T(x,y,z,t). This can be solved using the heat conduction equation:

[0327]

[0328] Among them, c p is specific heat capacity, k is thermal conductivity, and Q is internal heat source.

[0329] 2. Consider the effect of temperature on material properties. For example, the elastic modulus changes with temperature:

[0330] E(T)=E0(1-α E (T-T0))

[0331] Where E0 is the elastic modulus at reference temperature T0, and α E It is the temperature coefficient.

[0332] 3. Consider thermal stress. Thermal strain can be expressed as:

[0333] ε th =α th (T-T0)

[0334] Where, α th It is the coefficient of thermal expansion.

[0335] 4. Modify the total strain:

[0336] ε total =ε mechanical +ε th

[0337] Through the above detailed steps, a comprehensive mechanical analysis and multi-objective optimization framework was established for the design of steel structure box-type components. This framework considers various factors such as material nonlinearity, geometric nonlinearity, welding effects, corrosion, and temperature variations, and combines finite element analysis, reliability analysis, and fatigue analysis. Using the NSGA-II algorithm for multi-objective optimization, a series of Pareto optimal solutions that balance different objectives (such as mass, strength, and stiffness) can be obtained.

[0338] This optimization process determines the optimal range of key parameters such as the amplitude parameters (A1, A2) of the internal diaphragm shape function, the shape parameters (B1, B2, B3) of the web shape function, the number of stiffening ribs (n), the number of corrugated ribs (m), and the amplitude (A) and wavelength (λ) of the corrugated ribs. Optimizing these parameters will significantly improve the performance of the box-type component while meeting various engineering constraints and reliability requirements.

[0339] Finally, it is important to emphasize that while this framework provides a systematic approach to optimizing box-type component design, factors such as manufacturing processes and costs must be considered in practical applications. Furthermore, due to the complexity of the problem, experimental verification and further detailed analysis may be necessary to ensure the feasibility and reliability of the final design.

[0340] Specifically, the principle of this invention is:

[0341] 1. Steel Plate Pretreatment and Leveling Technology. Steel plates are prone to warping and deformation during transportation and storage, which affects subsequent cutting accuracy. This invention employs a combination of mechanical and chemical cleaning methods to thoroughly remove contaminants and oxide layers from the steel plate surface, creating favorable preconditions for subsequent leveling. Based on this, a professional hydraulic or CNC leveling machine is used to precisely level the steel plate. Multiple segmented leveling operations gradually eliminate initial deformation, ensuring the flatness of the steel plate meets design requirements. This series of pretreatment and leveling measures effectively controls the geometric accuracy of the steel plate before processing, laying a solid foundation for subsequent cutting and assembly.

[0342] 2. Optimized Internal Structure Design. Box-type steel structure members withstand complex compression, bending, and shear loads in practical applications; therefore, the design of their internal structure is crucial to overall performance. This invention utilizes mathematical modeling to design internal partitions with complex curved surfaces featuring a central protrusion and undulating edges, as well as web shapes incorporating multiple sine curves and quadratic functions. This structural design not only significantly enhances the overall stiffness and strength of the box-type member but also optimizes stress distribution and improves the structure's resistance to deformation. Furthermore, this invention introduces reinforcing ribs and corrugated ribs, using non-uniform distribution and complex geometry to specifically strengthen the support in areas of high stress, further improving overall performance.

[0343] 3. Assembly Process Optimization. During the assembly of box-type components, the relative positions and gap dimensions of each part must be strictly controlled to ensure the geometric accuracy of the overall structure. This invention focuses on optimizing the setting of the jig and ground line, improving the positioning accuracy of the bottom panel. Simultaneously, through computer-aided design, the installation positions and geometric parameters of the internal partitions, webs, reinforcing ribs, and corrugated ribs were precisely determined, ensuring accurate fit between components and meeting design standards. These optimization measures effectively solved the accuracy control problem during assembly, laying the foundation for subsequent welding and end-face machining.

[0344] 4. Application of Advanced Machining Technologies. In the welding and end-face machining stages, this invention employs advanced machining methods such as submerged arc welding and CNC milling. Submerged arc welding features high heat input and high weld quality, effectively controlling welding deformation and residual stress, thus improving the overall structural performance of the box-type components. Simultaneously, CNC milling ensures high-precision machining of the end faces, meeting assembly requirements. The application of these advanced technologies further enhances the manufacturing quality and performance of the box-type components.

[0345] In summary, this invention represents a systematic innovation in steel plate pretreatment, internal structural optimization design, assembly process optimization, and the application of advanced processing technologies. It effectively solves the precision control challenges existing in current technologies, laying a solid foundation for manufacturing high-quality steel structure box-type components. This comprehensive process optimization not only improves the structural performance of the box-type components but also significantly enhances the stability and reliability of the manufacturing process, which is of great significance for promoting steel structure engineering construction.

[0346] Two specific embodiments of the present invention are provided below.

[0347] Example 1: A large-scale steel structure project requires the manufacture of a batch of box-shaped steel components as main load-bearing parts. The dimensions of the box-shaped components are: width W = 1000mm, height H = 800mm, and length L = 6000mm. Based on the processing method proposed in this invention, the manufacturer successfully manufactured box-shaped components that meet the design requirements. The specific operation steps are as follows:

[0348] Step S10: Steel plate pretreatment

[0349] First, the steel plate to be processed undergoes surface cleaning. A shot blasting machine is used for mechanical cleaning, employing high-speed rotating metal particles to impact the steel plate and remove surface rust and dirt. After cleaning, the steel plate is pickled with a 5% hydrochloric acid solution to thoroughly dissolve and remove any remaining oxide scale. This pretreatment, combining mechanical and chemical cleaning, achieves a clean surface, laying the foundation for subsequent leveling processes.

[0350] Step S20: Steel plate leveling

[0351] The pre-treated steel plate is placed on a CNC horizontal leveling machine. The clamping and leveling forces are set appropriately based on the plate's thickness (20mm) and material (Q345B). First, the entire steel plate is roughly leveled to eliminate obvious warping. Then, it is subdivided into sections for fine leveling until the surface flatness meets the requirements. Through this segmented leveling method, the flatness of the steel plate is ultimately controlled within 1.5mm, conforming to the standards in the design drawings.

[0352] Step S30: CNC cutting

[0353] The leveled steel plate was placed on a CNC plasma cutting machine, and precision cutting was performed according to the CAD / CAM program design. The cutting parameters were set as follows: cutting speed 1.2 m / min, cutting current 300 A, and compressed air as the cutting gas. During the cutting process, the cutting gap was strictly controlled to avoid significant thermal deformation. This precision cutting process ensured that the dimensional accuracy of each part met the requirement of ±0.5 mm, laying the foundation for subsequent assembly.

[0354] Step S40: Secondary leveling

[0355] Since some deformation will still occur on the surface of the parts during the cutting process, a secondary leveling process is required. Using the same leveling method as in step S20, the parts are first roughly leveled to eliminate obvious deformation; then fine adjustments are made until the flatness of each part is controlled within 0.8mm. During the leveling process, special attention is paid to controlling the leveling force acting on the parts to avoid excessive stress that could cause new deformation. After the secondary leveling, the dimensional and geometric accuracy of each part is effectively guaranteed.

[0356] Step S50: Fixture and Ground Line

[0357] A sturdy steel jig was erected at the processing site, with its flatness controlled within 0.3 mm / m. On the upper surface of the jig, corresponding ground lines were drawn according to the design drawings. The position and dimensions of the ground lines were strictly arranged according to the drawing requirements to ensure that the relative positions and gaps of subsequent parts met the standards. By rationally setting up the jig and ground lines, a reliable benchmark and reference were provided for the assembly of the box-type components.

[0358] Step S60: Positioning the bottom panel

[0359] The cut bottom panel pieces are placed on the jig and precisely positioned according to the pre-drawn ground pattern lines. Laser alignment equipment is used to assist in positioning, ensuring that the center line of the bottom panel completely coincides with the ground pattern lines, and that the four corner points also fall within the ground pattern line range. After positioning, the bottom panel is initially fixed by manual spot welding. This precise positioning lays the foundation for the subsequent assembly of other parts.

[0360] Step S70: Internal parts assembly

[0361] According to the design drawings, the internal partitions and webs of the box-shaped component were placed sequentially on the bottom panel. Positioning pins and fixtures were used to assist in positioning, ensuring that the installation positions and clearances of each part met the requirements. Initial fixing was then achieved through spot welding, with evenly distributed welds and weld lengths and depths meeting strength standards. After fixing, the positions and angles of the parts were adjusted appropriately to ensure the geometric accuracy of the overall structure. Through the orderly assembly of the internal parts, the overall dimensions, shape, and assembly quality of the box-shaped component were ultimately achieved.

[0362] Step S80: Submerged arc welding

[0363] After assembling the internal parts, the entire box-shaped component was fully welded using submerged arc welding. The welding parameters were set as follows: welding current 500A, welding voltage 32V, and welding speed 30cm / min. By appropriately selecting these parameters, sufficient strength and toughness of the weld were ensured, while minimizing welding deformation. To further improve welding quality, a multi-layer welding method was employed, starting with root welding, followed by layer-by-layer filling and capping welding. This comprehensive submerged arc welding effectively guaranteed the overall structural stability and load-bearing capacity of the box-shaped component.

[0364] Step S90: End face machining

[0365] After welding, the end faces of the box-shaped components are precision machined using a CNC milling machine. The milling parameters are set as follows: milling cutter diameter 100mm, feed rate 0.2mm / r, and spindle speed 1200rpm. By properly adjusting these parameters, it is ensured that no significant vibration or burrs are generated during the end face machining process. After milling, manual polishing is performed to further improve the flatness and smoothness of the end face, meeting the accuracy requirement of ±0.05mm.

[0366] Through the meticulous operation of the above steps, the final manufactured box-shaped steel components fully meet the design standards in terms of geometric dimensions, structural performance, and welding quality, laying a solid foundation for subsequent overall installation.

[0367] Example 2: A large-scale highway bridge project requires a batch of box-section steel girders with a cross-sectional dimension of 800mm × 600mm and a length of 30m as the main beams. According to the design requirements, these box-section steel girders need to meet the following parameter constraints:

[0368] 1. Steel plate thickness t: 10mm ≤ t ≤ 50mm

[0369] 2. Steel plate flatness error δ: δ≤min(0.001L, 2mm), where L is the maximum side length of the steel plate.

[0370] 3. Box-type column cross-section dimensions W×H: 300mm≤W,H≤1500mm

[0371] 4. Deformation of the part after cutting Δ: Δ≤0.002×max(W,H,L)

[0372] 5. Flatness error of the jig frame ε: ε≤0.5mm / m

[0373] 6. Perpendicularity deviation between the bottom panel and the jig frame θ: θ≤0.1°

[0374] 7. Internal partition shape parameters: 0≤A1,A2≤0.05min(W,H),0.1min(W,H)≤σ≤0.3min(W,H)

[0375] 8. Web shape parameters: |B1|, |B2|≤0.02W, |B3|≤0.05W

[0376] 9. Number of reinforcing ribs n:

[0377] 10. Number of wavy ribs (m):

[0378] 11. Parameters for wavy ribs: 5mm≤A≤20mm, 50mm≤λ≤200mm, 0.2W≤σw≤0.4W

[0379] 12. Weld thickness tw: tw = min(0.7t, 12mm)

[0380] 13. End face machining accuracy P: P≤0.1mm

[0381] The manufacturer, using the processing method proposed in this invention and strictly adhering to the above parameter limitations, successfully manufactured box-section steel beams that meet the design requirements. The specific operating steps are as follows:

[0382] Step S10: Steel plate pretreatment

[0383] First, the surface of the 20mm thick Q345B steel plate was cleaned. Shot blasting was used to remove rust and dirt from the steel plate surface, followed by pickling with a 5% hydrochloric acid solution to thoroughly remove any remaining oxide layer. This combined mechanical and chemical cleaning method ensures the steel plate surface reaches an ideal clean state, meeting the requirements of subsequent leveling. According to the design drawings, the dimensions of the steel plate used are: length L = 30000mm, width W = 800mm, height H = 600mm, and thickness t = 20mm, meeting parameter constraint 1.

[0384] Step S20: Steel plate leveling

[0385] The cleaned steel plate is placed on a CNC horizontal leveling machine. The clamping and leveling forces are set appropriately based on the plate's geometry and material properties. First, the entire steel plate is roughly leveled, then fine-tuned in sections until the flatness error δ is less than 0.8mm, meeting parameter limit 2. This segmented leveling method effectively eliminates deformation of the steel plate during transportation and storage, laying the foundation for subsequent cutting and processing.

[0386] Step S30: CNC cutting

[0387] According to the CAD / CAM program, the leveled steel plate was placed on a CNC plasma cutting machine for precision cutting. The cutting parameters were set as follows: cutting speed 1m / min, cutting current 350A, and cutting gas nitrogen. During the cutting process, the cutting gap was strictly controlled to ensure that the dimensions of the parts met the requirements of the design drawings, i.e., the box-shaped column cross-section dimensions W×H=800mm×600mm, which meets parameter limit 3. After cutting, the dimensional accuracy of each part was controlled within ±0.3mm.

[0388] Step S40: Secondary leveling

[0389] Since some deformation will still occur on the surface of the parts during the cutting process, a secondary leveling process is required. Using the same leveling method as in step S20, the parts are first roughly leveled to eliminate obvious deformation; then fine adjustments are made until the maximum deformation Δ of each part is less than 12mm, meeting parameter constraint 4. This secondary leveling ensures the geometric accuracy of the cut parts, laying the foundation for subsequent assembly.

[0390] Step S50: Fixture and Ground Line

[0391] A sturdy and stable steel jig was erected at the processing site. Using a level, the flatness error ε of the jig was controlled within 0.3 mm / m, meeting parameter limit 5. Corresponding ground lines were drawn on the jig surface, and their position and dimensions were strictly determined according to the design drawings, providing a reliable benchmark for the subsequent positioning of the bottom panel.

[0392] Step S60: Positioning the bottom panel

[0393] The cut base panel is placed on the jig, and a laser alignment device is used to ensure that the center line of the base panel is completely aligned with the ground pattern line, while the four corner points also fall within the ground pattern line range. Through this precise positioning, the perpendicularity deviation θ between the base panel and the jig is controlled within 0.05°, meeting the parameter limit 6 requirement. After positioning, the base panel is initially fixed by spot welding.

[0394] Step S70: Internal parts assembly

[0395] According to the design drawings, the internal partitions are first placed on the bottom panel. The shape of the partitions is determined by a function. It is determined that A1 = 40mm, A2 = 30mm, and σ = 160mm, which satisfies parameter constraint 7.

[0396] Next, the web is placed, its shape determined by a function. It is determined that B1 = 15mm, B2 = 12mm, and B3 = 30mm, which satisfies parameter constraint 8.

[0397] In addition, reinforcing ribs and corrugated ribs are installed in appropriate locations. The number of reinforcing ribs, n = 5, and their installation locations are determined by a function. Confirmed, parameter constraint 9 is met; the number of wavy ribs m = 7, and the installation position is determined by the function. The shape of the wavy rib is determined by the function. Description, satisfying parameter constraints 10 and 11.

[0398] Through orderly assembly of internal parts, the relative positions, dimensional clearances, and geometric shapes of all components of the box-shaped structure were ensured to meet design standards. To further secure these parts, initial connections were made using spot welding, with evenly distributed weld points and weld lengths and depths meeting strength requirements. After securing, the positions and angles of the parts were appropriately adjusted, ultimately achieving high-precision assembly of the overall structure.

[0399] Step S80: Submerged arc welding

[0400] After all internal parts were in place, the entire box-shaped component was fully welded using submerged arc welding. The welding parameters were set as follows: welding current 550A, welding voltage 34V, and welding speed 35cm / min. By properly controlling these parameters, the weld thickness t could be ensured. w Satisfying t w =min(0.7t, 12mm) = 14mm, which meets the parameter limit of 12. To further improve the welding quality, a multi-layer welding method is adopted, first performing root welding, and then performing fill and cover welding in layers. This comprehensive submerged arc welding effectively controls welding deformation and residual stress, ensuring the overall structural stability of the box-shaped component.

[0401] Step S90: End face machining

[0402] Finally, the welded box-shaped component was machined on its end face using a CNC horizontal milling machine. The milling parameters were set as follows: cutter diameter 125mm, feed rate 0.15mm / r, and spindle speed 1500rpm. By adjusting these parameters appropriately, the end face machining accuracy P was controlled.

[0403] Within 0.08mm, the parameter limit 13 is met. After milling, manual polishing is used to further improve the flatness and smoothness of the end face.

[0404] Through meticulous processing of the above steps, the final manufactured box girder fully meets design standards in terms of dimensional accuracy, structural performance, and welding quality. The following are the key parameter data for this box girder:

[0405] Steel plate thickness t = 20mm

[0406] The flatness error of the steel plate is δ = 0.6 mm.

[0407] The cross-sectional dimensions of the box-type column are W×H = 800mm × 600mm.

[0408] The maximum deformation of the part after cutting is Δ = 9mm.

[0409] The flatness error of the jig frame is ε = 0.4 mm / m

[0410] The perpendicularity deviation between the bottom panel and the jig is θ = 0.08°.

[0411] Internal partition shape parameters: A1 = 40mm, A2 = 30mm, σ = 160mm

[0412] Web shape parameters B1 = 15mm, B2 = 12mm, B3 = 30mm

[0413] Number of reinforcing ribs n = 5

[0414] Number of wavy ribs m = 7

[0415] The wavy rib parameters are A = 12mm, λ = 100mm, and σw = 0.3W.

[0416] Weld thickness tw = 14mm

[0417] End face machining accuracy P = 0.08mm

[0418] By comparing the above parameter values ​​with the design requirements, it can be seen that the processing method proposed in this invention fully meets all parameter limitations, ensuring the manufacturing quality of the box girder. This batch of box girder was successfully applied to this large-scale bridge project, demonstrating excellent performance in overall structural safety and service life, providing solid support for the project construction.

[0419] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of processing a steel structural box member, characterized by, Includes the following steps: S10. Pre-treat the steel plate, including cleaning surface impurities and removing rust; S20. Use professional leveling equipment to level the steel plate to ensure flatness; S30. According to the design drawings, use CNC cutting equipment to cut the steel plate and parts into blanks; S40. Perform secondary straightening on the cut parts to eliminate deformation caused during the cutting process; S50. Set up a jig at the processing site and place a ground line on the jig to provide a reference for subsequent assembly; S60. Locate and place the bottom panel of the box column according to the ground line; S70. Assemble the internal partitions, web plates, and reinforcing structures in sequence according to the design requirements, and fix them by spot welding. S80. Use submerged arc welding to weld the box-type components as a whole to ensure the integrity and strength of the structure. S90. Perform end face milling on the welded box-shaped components to ensure the flatness and accuracy of the end faces, and complete the processing and manufacturing. The reinforcing structure includes reinforcing ribs and corrugated ribs; The shape of the internal partition is defined by the following function: ； in, The width of the box-shaped column. The height of the box-type column must satisfy the following conditions: , and For amplitude parameters, Let be the standard deviation of the Gaussian function, satisfying: , x represents the coordinate along the width of the box column; y represents the coordinate along the height of the box column; z represents the coordinate perpendicular to the plane of the box column, that is, the thickness or shape of the box component. The shape of the web is defined by the following function: ； in, , , For shape parameters, satisfying: , ; The installation position of the reinforcing rib is defined by the following function: ， ； in, To increase the number of ribs; The installation position and number of the wavy ribs are defined by the following function: ， ； in, The number of wavy ribs.

2. The method for processing steel structure box-type components according to claim 1, characterized in that, The shape of the wavy rib is defined by the following function: ； in, For amplitude, For wavelength, Let the standard deviation of the Gaussian envelope satisfy: , , .

3. The method for processing steel structure box-type components according to claim 2, characterized in that, The number of reinforcing ribs The method for determining it is as follows: 。 4. A method for processing steel structure box-type components according to claim 3, characterized in that, The number of wavy ribs The method for determining it is as follows: 。

Images