A method of manufacturing a steel structure without excess

Abstract

A kind of excess-free manufacturing method of steel structure, including determining processing shrinkage A1, pyrotechnic shrinkage A2, compensation B and steel structure processing four steps, steel structure component will high-temperature expansion in the welding process, after cooling, steel structure component welding will shrink, therefore produce processing shrinkage A1, since steel structure will produce deformation in the process processing, therefore need to be corrected by pyrotechnic and make steel structure reach the standard size and shape of design requirement, therefore produce pyrotechnic shrinkage A2, to make the size of steel structure component not change after welding processing and pyrotechnic correction, the size consumed by steel structure component is arranged in advance, i.e. B=A1+A2, the size of original design requirement steel structure component size plus B size, then it is the final size of steel structure component, then carry out processing to the final size steel structure, then excess-free steel structure can be obtained, finally realize excess-free steel structure construction.

Description

Technical Field

[0001] This invention belongs to the field of steel structure bridge construction technology, specifically relating to a method for manufacturing steel structures without margin. Background Technology

[0002] The steel structure manufacturing process involves steps such as parts cutting, unit assembly, and segment assembly, each of which introduces certain processing errors. These errors can lead to dimensional deviations in the steel structure, resulting in reduced dimensions and making further assembly or installation impossible. To compensate for these manufacturing errors and ensure the final shape and dimensions meet specified precision requirements, designers add a certain amount of manufacturing allowance during parts layout. However, controlling this allowance is challenging, and its precise value cannot be guaranteed, still leading to dimensional deviations in the final steel structure and consequently reducing installation accuracy.

[0003] Due to the high precision requirements and large welding deformation of steel structures, in order to ensure that the dimensions of unit components and segments meet the precision requirements, a 20mm workshop process allowance is usually added to the ends when laying out the parts. After the steel structure is assembled, the workshop process allowance at the ends is matched and beveled. For the closure segment, a 50mm-100mm closure allowance is added to one side. The matching is carried out according to the on-site installation. Then, the steel structure segments are spliced ​​through a high-precision assembly sequence to complete the construction of the required steel structure.

[0004] For example, the authorized patent number CN201711217069.X describes a method for manufacturing the lower chord steel box girder of a bridge composed of a fully welded steel box girder and a fully bolted truss. This method defines the allowance for the parts and units that need to be welded during the splicing of the box girder, thereby improving the assembly accuracy of the box girder. However, this invention only defines the range of allowances that the parts and units of the steel box girder will generate, but does not clearly define the allowances required for the internal components of the steel structure under different processes. Therefore, it is still impossible to achieve zero-allowance construction of steel structures.

[0005] The construction of the steel structure mentioned above will leave excess industrial allowance. In order to ensure the manufacturing accuracy of the steel structure in the factory, the segment needs to be measured after completion and the excess process allowance needs to be flame-cut. This will result in unevenness at the segment ends, requiring repair and grinding later, which is time-consuming and labor-intensive. Summary of the Invention

[0006] This invention provides a method for manufacturing steel structures without margin, which controls the precision of the steel structure at each process, and finally realizes the construction of steel structures without margin. This avoids the later flame cutting step, thereby improving the quality of the segment ends and avoiding the later repair and grinding process, further improving the processing efficiency.

[0007] A method for manufacturing steel structures without allowances includes the following steps:

[0008] S01. Steps for determining the value of the processing shrinkage A1 of steel structures;

[0009] In this step, the amount of loss generated during the steel structure's processing is called the processing shrinkage A1.

[0010] S02, Steps for determining the value of the thermal shrinkage A2 of steel structures;

[0011] In this step, the amount of loss generated in the steel structure during the fire straightening process is called fire shrinkage A2.

[0012] S03, Calculation steps for the required compensation amount B of the steel structure;

[0013] In this step, the compensation amount B is calculated by waiting for the steel structure to be added.

[0014] S04. Steel structure processing steps;

[0015] The steel structure components are fabricated with an additional compensation amount B on top of their original dimensions.

[0016] As a preferred embodiment of the present invention, in S01, the processing shrinkage A1 includes one or more of the following: fillet weld processing shrinkage A11, submerged arc welding processing shrinkage A12, and shielded welding processing shrinkage A13.

[0017] As a preferred embodiment of the present invention, 3. the shrinkage amount A11 of the fillet weld includes the length shrinkage amount Vx and the width shrinkage amount Vy;

[0018] The length shrinkage Vx = (1.09 - 0.028t) / Lsx * W, where t is the thickness of the steel structure, Lsx is the spacing between components arranged along the length of the steel structure, and W is the welding coefficient;

[0019] The width shrinkage amount Vy = (1.1 - 0.05t) / Lsy * W, where t is the thickness of the steel structure, Lsy is the spacing between components arranged on the width of the steel structure, and W is the welding coefficient.

[0020] As a preferred embodiment of the present invention, when the thickness of the steel structure is less than 16mm, the value of the submerged arc welding processing shrinkage A12 is 0; when the thickness of the steel structure is greater than or equal to 16mm, the value of the submerged arc welding processing shrinkage A12 is 4mm.

[0021] As a preferred embodiment of the present invention, the shrinkage amount of the protective welding process A13 = at + bs + c, where a is the bevel parameter, b is the empirical value of the bevel blunt edge, c is a fixed amount, t is the thickness of the steel structure, and s is the bevel gap.

[0022] As a preferred embodiment of the present invention, in S02, the pyrotechnic shrinkage A2 = 1 / 1000*L, where L is the length of the steel structure component.

[0023] As a preferred embodiment of the present invention, in S03, the compensation amount B is the sum of the value of the processing shrinkage amount A1 and the value of the firework shrinkage amount A2.

[0024] As a preferred embodiment of the present invention, the steel structure includes a base plate 1, a partition plate 2, a web plate 3, a top plate 4, and a crossbeam 5. In step S04, the processing steps of the steel structure are as follows: first, the partition plate 2 is evenly distributed on the base plate 1, the web plate 3 is installed on both sides of the base plate 1, and then the top plate 4 is installed on the top of the base plate 1 to form a steel structure box girder. After assembly, two adjacent steel structure box girders are connected by the crossbeam 5.

[0025] As a preferred embodiment of the present invention, the zero-margin construction method further includes S05, a verification step; verifying and checking the dimensions of the steel structure processed in S04 against the dimensions of the target steel structure to check the error range.

[0026] As a preferred embodiment of the present invention, if the error range in S05 is within the usable range, the steel structure shall be used for construction; if it exceeds the usable range, the steel structure shall be reforged.

[0027] In summary, the present invention has the following beneficial effects:

[0028] 1. By refining the shrinkage caused by the processing technology of internal steel structure components, compensation amounts are pre-planned and specified for each part and unit inside the steel structure, as well as the large components of the steel structure such as top plate, partition plate, web plate, beam and bottom plate. This ensures that the splicing dimensions of the steel structure will not change, reduces the difficulty of accurately measuring the allowance, and thus improves the accuracy of steel structure splicing.

[0029] 2. Deformation of steel structure components caused by welding is corrected by flame straightening. The shrinkage caused by flame straightening is preset and the compensation amount is preset so that the steel structure will not have dimensional deviations during the flame straightening process, thereby improving the accuracy of steel structure splicing and avoiding subsequent repair and grinding processes, thus further improving processing efficiency.

[0030] 3. By inspecting the deviations generated during the manufacturing process of the steel structure, the splicing error of the steel structure can be reasonably controlled, the overall splicing accuracy of the steel structure can be improved, so that the manufactured steel structure has no process allowance, thus preventing and avoiding the later flame cutting steps and improving the quality of the segment ends. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a steel structure segment.

[0032] Figure 2 This is a schematic diagram of the steel structure splicing.

[0033] Figure 3 This is a schematic diagram of a single-section steel structure.

[0034] Figure 4 This is a partial schematic diagram of the steel structure.

[0035] Figure reference numerals: base plate 1, base plate longitudinal rib 11, partition plate 2, web plate 3, web plate longitudinal rib 31, top plate 4, U-rib 41, crossbeam 5. Detailed Implementation

[0036] A method for manufacturing steel structures without margin includes four steps: determining the processing shrinkage A1, the fire shrinkage A2, the compensation amount B, and the steel structure processing. The compensation amount B = A1 + A2. The above values ​​and processing methods are explained below.

[0037] Processing shrinkage A1: Due to the high temperature expansion of steel structure components during welding, the welded joints of the steel structure components will shrink after cooling, resulting in processing shrinkage A1. Moreover, the shrinkage A1 of steel structure components will be different under different welding processes. Therefore, it is necessary to determine the value of steel structure A1 under different processes by using formula method or definition method.

[0038] Firework shrinkage A2: Because steel structures deform during processing, firework straightening is required to bring them to the standard dimensions and shapes required by the design. Firework straightening involves heating the components at high temperatures, applying force through mechanical pressure or other tools to adjust the shape of the parts, and then cooling them. During this process, both the adjustment and cooling steps will cause dimensional loss in the steel structure components, reducing their size and thus generating firework shrinkage A2. The value of firework shrinkage A2 is determined according to the degree of firework straightening required for different components.

[0039] Compensation amount B: As mentioned above, the steel structure components will shrink by A1 and A2 during welding and heat treatment. In order to ensure that the dimensions of the steel structure components do not change after welding and heat treatment, the compensation amount B is preset in advance, which means that the dimensions of the steel structure components will be consumed in advance, i.e., B = A1 + A2.

[0040] Steel structure fabrication: After obtaining the value of B through the above method, the dimensions of the steel structure components required by the original design are added to the dimension of B to obtain the final dimensions of the steel structure components. Then, the steel structure with the final dimensions is fabricated to obtain a steel structure with no margin, thus realizing the construction of a steel structure with no margin.

[0041] As attached Figure 1-4 As shown, the steel structure includes a base plate 1, partition plates 2, web plates 3, top plate 4, and crossbeams 5. The partition plates 2 are evenly distributed on the base plate 1, the web plates 3 are installed on both sides of the base plate 1, and the top plate 4 is installed on the top of the base plate 1 to form a steel structure box girder. The crossbeams 5 connect two adjacent steel structure box girders. The base plate 1 is provided with base plate longitudinal ribs 11, the web plate 3 is provided with web plate longitudinal ribs 31, and the top plate 4 is provided with U-ribs 41.

[0042] In S01, the steel structure is processed through different processes. The processing shrinkage A1 includes fillet weld processing shrinkage A11, submerged arc welding processing shrinkage A12, and shielded welding processing shrinkage A13. The welding process of fillet weld processing shrinkage A11 typically involves heating and melting the component at the corner and applying appropriate welding materials (welding wire, welding rod, etc.) to achieve the connection. Submerged arc welding processing shrinkage A12 is generated by burning in the welding area under the weld, while the arc and molten metal are covered by a layer of powder or granular welding shielding material, forming an arc that is "buried" under the weld. Shielded welding processing shrinkage A13 is generated by using a welding torch with a welding wire electrode. The welding wire enters the welding area through the welding torch and melts under the action of the arc. At the same time, inert gas (CO2) is sprayed into the welding area through the gas nozzle of the welding torch, forming a shielding gas environment. This shielding gas environment can prevent oxygen and moisture in the air from entering the welding area, thereby reducing oxidation and porosity and improving welding quality.

[0043] The value of the processing shrinkage A1 produced by the steel structure processed in the above manner will also be different. If the fillet weld is used, the fillet weld will produce a fillet weld processing shrinkage A11 in both the length and width directions of the steel structure. Taking the partition 2 and the base plate 1 as a unit, and the fillet weld between the partition 2 and the base plate 1 changing in the length direction as an example, the partition 2 is installed horizontally and evenly on the base plate 1 with the width of the base plate 1 as the reference. The fillet weld is used between the partition 2 and the base plate 1. Then the base plate 1 will produce a shrinkage in length. Taking the weld leg height of 4.5 as the reference, the formula for the shrinkage in the length direction of the base plate 1 is Vx=(1.09-0.028t) / Lsx*W (mm), where t is the thickness of the steel plate (mm), Lsx is the spacing of the partition 4 (m), W is the welding coefficient, which is taken as 1.0. Vx is calculated as the shrinkage in the length direction of the fillet weld per 1m. The value obtained by substituting the above values ​​is the fillet weld processing shrinkage A11.

[0044] If the fillet weld of the steel structure adopts double-sided bevel deep penetration welding, the welding coefficient is 2.0, and the processing shrinkage A11 of the fillet weld in the length direction of the unit is 2*Vx (mm). If the fillet weld of the steel structure adopts double-sided bevel full penetration welding, the welding coefficient is 2.5, and the processing shrinkage A11 of the fillet weld in the length direction of the unit is 2.5*Vx (mm).

[0045] Taking the base plate 1 and the base plate longitudinal rib 11 as unit components, the base plate longitudinal rib 11 is installed longitudinally on the base plate 1 with the base plate 1 length as the reference. The base plate longitudinal rib 11 and the base plate 1 are connected by fillet welds. Then the base plate 1 will have a shrinkage in width. With the weld leg height of 4.5 as the reference, the shrinkage in width direction of the base plate 1 is calculated as Vy = (1.1 - 0.05t) / Lsy * W (mm), where t is the thickness of the steel plate (mm), Lsy is the spacing of the longitudinal ribs 11 (m), W is the welding coefficient, which is 1.0, and Vy is the shrinkage in width direction between each base plate 1 and the longitudinal rib 11. The value obtained by substituting the above values ​​is the shrinkage A11 of the fillet weld processing.

[0046] If the fillet weld of the steel structure adopts double-sided bevel deep penetration welding, the welding coefficient is 2.0, and the fillet weld processing shrinkage A11 on the width of the fillet weld of the unit is 2*Vy (mm). If the steel structure adopts double-sided bevel full penetration welding, the welding coefficient is 2.5, and the fillet weld processing shrinkage A11 on the width of the fillet weld of the unit is 2.5*Vy (mm).

[0047] If the steel structure is processed using submerged arc welding, a beveling preparation is required before the parts are joined for automatic submerged arc welding. The beveling involves cutting or trimming the material on both sides or the bottom of the parts to be welded to create a shape that can accommodate the weld metal. If the thickness of the steel plate of the parts to be welded is less than 16mm, a beveling is not required, and the parts can be directly joined for automatic submerged arc welding, with a submerged arc welding shrinkage A12 value of 0. If the thickness of the steel plate of the parts to be welded is greater than or equal to 16mm, a beveling of 4mm is required, with a submerged arc welding shrinkage A12 value of 4mm.

[0048] If the steel structure is processed using shielded welding, this embodiment uses CO2 gas shielded welding. During the welding process, the formula for calculating the shrinkage A13 of the shielded welding is Pm=at+bs+c (mm). Taking a steel plate thickness of 16mm and a bevel gap of 6mm as an example, where a is the empirical value of the bevel parameter (0.08), b is the empirical value based on the bevel blunt edge (0.18), c is the quantitative value of the bevel surface structure type (0.94), t is the steel plate thickness, and s is the bevel gap. By substituting the above values, we can obtain that the Pm of the butt weld is 3.3mm. Pm is the shrinkage A13 of the shielded welding of the butt weld, so the shrinkage A13 of the shielded welding on one side is 1.5-2.0mm.

[0049] In S02, when the steel structure components are heat-straightened, the heat-straightening will change the size of the steel structure components. Since the steel structure component will generate a heat shrinkage amount A2 of 1mm for every 1000mm of its length, the formula for calculating the heat shrinkage amount A2 of the steel structure is 1 / 1000*L (mm). If the obtained value is less than 5mm, the heat shrinkage amount A2 is set to 5mm.

[0050] For details, see attached. Figure 2-4 As shown, the welding of U-ribs 41 on the top plate 4 is carried out by a welding robot, and the welding heat is relatively uniform. At the same time, a straightening machine is used to straighten the top plate 4, so there is basically no deformation. Therefore, the top plate 4 does not need to be straightened by fire. The web plate 3 is provided with web longitudinal ribs 31. Since the number of web longitudinal ribs 31 is small and the welding process between the web plate 3 and the web longitudinal ribs 31 is relatively simple, the amount of deformation caused by welding is small. Therefore, the minimum fire straightening compensation amount of 5mm can be used. The bottom plate 1 and the bottom plate longitudinal ribs 11 are connected by double-sided bevel deep penetration welding. The amount of welding is large and the deformation and shrinkage are also large. Therefore, a fire compensation amount of 1 / 1000*L (mm) needs to be added. The crossbeams 2 and the partitions 5 are processed less and have basically no deformation. Therefore, no fire straightening is required and no fire compensation amount is added.

[0051] As can be seen from the above, the value of the steel structure processing shrinkage A1 is different under different processes. Then, the heat treatment shrinkage A2 can be obtained by calculation. The compensation amount B = processing shrinkage A1 + heat treatment shrinkage A2.

[0052] The compensation amount B obtained above is added to the original size of the steel structure before formal processing, ensuring that the size of the steel structure after processing still conforms to the original design size, realizing the construction of a steel structure with no margin, and avoiding the later flame cut-off step.

[0053] The steel structure fabrication in S04 includes the fabrication of the base plate 1, partition plate 2, web plate 3, top plate 4, and crossbeam 5. The fabrication is carried out according to the installation steps of the steel structure drawings. First, a jig is set up on the site, and the base plate 1 is placed on the jig. The partition plate 2 is evenly distributed on the base plate 1. The web plate 3 is installed on both sides of the base plate, ensuring that the horizontal baseline of the web plate 3 coincides with the horizontal baseline of the base plate 1. Then, the top plate 4 is installed on top of the base plate 1, corresponding to the position of the base plate 1, forming a single-section box girder of the steel structure. Finally, the adjacent single-section box girders are connected by the crossbeam 5. The crossbeam 5 is evenly distributed outside the single-section box girder, with the position of the partition plate 2 inside the single-section box girder as the reference.

[0054] A method for manufacturing steel structures without margin also includes step S05, verification step: verifying and checking the dimensions of the steel structure processed in step S04 against the dimensions of the target steel structure to check the error range.

[0055] Check the dimensional deviations of the parts after cutting: If the parts are cut by CNC cutting, the allowable deviation of the external dimensions is ±1mm; if the parts are cut by manual gas cutting, the allowable deviation of the dimensions should be ±2mm, and other dimensional deviations should comply with the requirements of JTG-T3651-2022 (Specification for Manufacturing and Installation of Steel Structure Bridges for Highways).

[0056] Check the dimensional deviations of the unit components after welding: For plate unit components (such as top plate unit 1, web plate unit 3, bottom plate unit 5, etc.), the accuracy of the plate unit is mainly controlled by data such as length, width and diagonal length. The allowable deviation for length and width is ±2mm, and the allowable deviation for diagonal length is ±4mm. Other allowable deviations in the assembly dimensions of the plate unit should comply with the requirements of JTG-T3651-2022 (Specification for Manufacturing and Installation of Steel Structure Bridges for Highways).

[0057] Check the dimensional deviations of steel structure segments after welding: When assembling and installing steel structure segments, it is necessary to ensure that the misalignment is less than or equal to 1mm, the allowable deviation of the length and width of the steel structure segments is ±4mm, and other dimensional deviations should comply with the requirements of JTG-T3651-2022 (Specification for Manufacturing and Installation of Highway Steel Structure Bridges).

[0058] If the steel structure meets the above error range, it can be used and processed normally. If the steel structure does not meet the above error range, it needs to be reforged to prevent problems from occurring in subsequent processing and use.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention; therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0060] Although this document makes extensive use of terms corresponding to the figure labels, the possibility of using other terms is not excluded; these terms are used merely to more conveniently describe and explain the essence of the invention; interpreting them as any kind of additional limitation would be contrary to the spirit of the invention.

Claims

1. A method of manufacturing a steel structure with no excess material, characterized in that, The steel structure comprises a bottom plate (1), a partition plate (2), a web plate (3), a top plate (4) and a cross beam (5), the processing steps of the steel structure are as follows: the partition plate (2) is uniformly arranged on the bottom plate (1), the web plate (3) is installed on both sides of the bottom plate (1), the top plate (4) is installed on the top of the bottom plate (1), a steel structure box beam is formed, and finally two adjacent steel structure box beams are connected through the cross beam (5); and the method comprises the following steps: S01, a processing shrinkage A1 value determination step of the steel structure In this step, the loss amount generated in the process of the steel structure, i.e., the processing shrinkage A1, is determined. S02, a firework shrinkage A2 value determination step of the steel structure In this step, the loss amount generated in the firework correction process of the steel structure, i.e., the firework shrinkage A2, is determined. S03, a calculation step of a required compensation amount B of the steel structure In this step, the size required to be added to the steel structure is the compensation amount B. S04, a steel structure processing step The steel structure parts are processed on the basis of the original size plus the size of the compensation amount B. The compensation amount B is the sum of the processing shrinkage A1 value and the firework shrinkage A2 value. In the S01, the processing shrinkage A1 comprises an angle weld processing shrinkage A11. The angle weld processing shrinkage A11 comprises a length shrinkage Vx and a width shrinkage Vy. The processing shrinkage A1 values generated by the steel structures processed by different processing methods are also different, when the angle welding method is adopted, the angle weld processing shrinkage A11 is generated in the length direction and the width direction of the steel structure, at this time, the partition plate and the bottom plate are taken as a unit element, the partition plate is uniformly installed on the bottom plate with the bottom plate width as the reference, the angle weld is adopted between the partition plate and the bottom plate, then the bottom plate will generate the shrinkage in the length direction, with the weld leg height of 4.5 as the reference, the bottom plate length direction shrinkage is Vx. The bottom plate and the bottom plate longitudinal rib are taken as a unit element, the bottom plate longitudinal rib is installed on the bottom plate in the longitudinal direction with the bottom plate length as the reference, the angle weld is adopted between the bottom plate longitudinal rib and the bottom plate, then the bottom plate will generate the shrinkage in the width direction, with the weld leg height of 4.5 as the reference, the bottom plate width direction shrinkage formula is Vy. When the steel structure angle weld adopts the double-bevel deep penetration welding, the welding coefficient is taken as 2.0, the angle weld processing shrinkage A11 of the unit element in the length direction is 2*Vx (mm), and the angle weld processing shrinkage A11 of the unit element in the width direction of the angle weld is 2*Vy (mm); when the steel structure angle weld adopts the double-bevel full penetration welding, the welding coefficient is taken as 2.5, the angle weld processing shrinkage A11 of the unit element in the length direction is 2.5*Vx (mm), and the angle weld processing shrinkage A11 of the unit element in the width direction of the angle weld is 2.5*Vy (mm). The length shrinkage Vx=(1.09-0.028t) / Lsx*W, t is the thickness of the steel structure, Lsx is the distance between the parts arranged in the length direction of the steel structure, W is the welding coefficient, W is taken as 1.0, and Vx is calculated as the shrinkage in the length direction of each 1 m angle weld. The width contraction amount Vy=(1.1-0.05t) / Lsy*W, t is the thickness of the steel structure, Lsy is the spacing between components arranged on the width of the steel structure, W is the welding coefficient, W is 1.0, Vy is the width direction contraction amount between each bottom plate and longitudinal rib; The explosive shrinkage A2=1 / 1000*L, wherein L is the length of the steel structure component, when the obtained value is less than 5mm, the explosive shrinkage A2 is set to 5mm.

2. A method of manufacturing a steel structure without excess material according to claim 1, characterized in that, The processing shrinkage A1 further includes one or more of submerged arc welding processing shrinkage A12 and shielded welding processing shrinkage A13.

3. A method of manufacturing a steel structure without excess material according to claim 2, characterized in that, When submerged arc welding is used for processing, groove preparation is needed before automatic submerged arc welding of part butt joint, the groove preparation is to cut or cut material on both sides or bottom of the part to be welded to form a shape convenient for containing welding material; when the thickness of the steel structure is less than 16mm, the value of the submerged arc welding processing shrinkage A12 is 0; when the thickness of the steel structure is greater than and equal to 16mm, the value of the submerged arc welding processing shrinkage A12 is 4mm.

4. A method of manufacturing a steel structure without excess material according to claim 2, characterized in that, When shielded welding is used for processing, CO2 gas shielded welding is used, and during the welding process, the shielded welding processing shrinkage A13 of the seam welding is at+bs+c, wherein a is the groove parameter, b is the empirical value of the groove land, and c is the constant, t is the thickness of the steel structure, and s is the groove gap.

5. A method of manufacturing a steel structure without excess material according to claim 1, characterized in that, The net stock manufacturing method further comprises S05, a checking step; The size of the steel structure processed in S04 is checked and compared with the target steel structure size, and the error range is checked.

6. A method of manufacturing a steel structure without excess material according to claim 5, characterized in that, If the error range in S05 is within the usable range, the steel structure is used for manufacturing, and if it exceeds the usable range, the steel structure needs to be re-forged.

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