Joint welding method applied to arc-shaped tunnel steel pipe pieces

Abstract

The invention discloses a seam welding method applied to arc-shaped tunnel steel pipe pieces. The seam welding method specifically comprises the following steps that S1, preparation is conducted; s2, preheating, wherein uniform preheating treatment is conducted on the joints; s3, positioning and welding, specifically, positioning and welding are conducted at the joints so as to fix the positions of the arc-shaped tunnel steel pipe pieces; s4, formal welding is conducted, specifically, a welding robot is adopted for conducting formal welding on the seam; s5, post-weld heat treatment is carried out; s6, inspection and correction are conducted, specifically, after welding is completed, seams are inspected, and defects are found and corrected in time; and S7, data uploading and recording: all parameters in the welding record and detailed data of heat treatment are uploaded to the system. According to the method, the position of the welding seam is divided into a plurality of welding layers, each layer is subdivided into a plurality of welding positions, the height of each layer of welding seam is 3-5 mm, and local heat treatment is carried out after each welding process is completed, so that the stress generated by the welding process is eliminated, and the microstructure is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel steel pipe segment welding, and in particular relates to a method for welding seams of arc-shaped tunnel steel pipe segments. Background Art

[0002] The application of steel pipe segments in complex sections such as connecting passages of subway tunnels and sharp curve tunnels is indeed very extensive, which is mainly due to their good structural performance and adaptability.

[0003] However, the complex structure of steel pipe segments and the various forms of steel plate joints pose considerable challenges to processing and manufacturing. At present, most steel pipe segment processing still relies on manual welding. Although this method can meet production needs to a certain extent, it has the following problems:

[0004] First, the quality is uneven. Due to differences in welding workers' technical level, work experience, operating habits and other factors, it is difficult to ensure the consistency of the quality of welding joints. This will not only affect the overall structural strength of the steel pipe segment, but may also bring safety hazards to the subsequent construction and use of subway tunnels.

[0005] Second, the repair rate of manual welding is high. Due to the instability of welding quality, defects such as weld cracking, slag inclusion, and lack of fusion often occur, which requires repair. This not only increases production costs, but also delays the progress of the project.

[0006] Third, the welding efficiency is low. Compared with automated welding, manual welding requires more time and manpower, and cannot meet the needs of large-scale, high-efficiency production. With the rapid development of subway construction, the demand for steel pipe segments is increasing, and the low efficiency of manual welding has become a bottleneck restricting production capacity.

[0007] Fourth, the cost is high. In addition to labor costs, there are additional costs caused by quality problems and rework. Summary of the invention

[0008] The purpose of the present invention is to propose a method for welding the seams of arc-shaped tunnel steel pipe segments in order to solve the problems of uneven quality, high rework rate, low welding efficiency and high cost caused by manual welding in the existing arc-shaped tunnel steel pipe segment welding.

[0009] In order to achieve the above object, the present invention adopts the following technical solution: a method for welding the seam of a curved tunnel steel pipe segment, specifically comprising the following steps:

[0010] S1: Preparation step, precisely align the arc-shaped tunnel steel pipe segments to be welded according to the design requirements, and clean the oil and impurities at the joints;

[0011] S2: Preheating step, uniformly preheating the joint to reduce stress and cracks generated during welding;

[0012] S3: Positioning welding step, performing positioning welding at the joint to fix the position of the arc-shaped tunnel steel pipe segment to prevent displacement during subsequent welding;

[0013] S4: Formal welding step, using a welding robot to perform formal welding on the joint. The formal welding adopts a multi-layer and multi-pass welding method. After each welding step or layer is completed, local heat treatment is performed to eliminate welding stress and improve the microstructure;

[0014] S5: Post-weld heat treatment step, after all welding layers are completed, the final overall heat treatment is carried out to further eliminate residual stress and improve the microstructure of the weld and heat-affected zone;

[0015] S6: Inspection and correction step: after welding, the joints are inspected and any defects found are corrected in time;

[0016] S7: Data upload record, the welding robot uploads all parameters in the welding record and detailed data of the heat treatment to the system, including the holding temperature, holding time, heating speed, and cooling speed, for subsequent quality control and traceability.

[0017] As a further description of the above technical solution:

[0018] The preheating temperature in S2 is 50-200°C.

[0019] As a further description of the above technical solution:

[0020] The tack welding in S2 and the formal welding in S3 use the same welding materials and welding process.

[0021] As a further description of the above technical solution:

[0022] The inspection in S6 adopts ultrasonic inspection or X-ray inspection.

[0023] As a further description of the above technical solution:

[0024] The height of each weld seam in S4 is 3-5 mm.

[0025] As a further description of the above technical solution:

[0026] A filling robot is arranged on one side of the welding robot, and the filling robot is used to fill the places with large gaps at the joints to achieve uniform welding at the joints.

[0027] As a further description of the above technical solution:

[0028] The welding robot in S4 uses a laser welding system to weld the joints of the steel pipe segments before formal welding, thereby creating an initial melting area at the joints to facilitate subsequent welding.

[0029] As a further description of the above technical solution:

[0030] At the same time or after laser welding, an ultrasonic vibration tool is used to apply mechanical vibration to the welding area. The frequency of the ultrasonic wave is above 20kHz, which produces tiny displacements, promotes the mixing and solidification of the molten metal, eliminates pores, refines the grain structure, and improves the strength and toughness of the weld joint.

[0031] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0032] 1. In the present invention, the position of the weld is divided into multiple welding levels, each level is further divided into multiple welding positions, the height of each weld is 3-5 mm, and the width of each weld is kept within the design requirements; after each welding is completed, local heat treatment is performed to eliminate the stress generated by the welding and improve the microstructure. The local heat treatment can be performed by a heating blanket, induction heating or a small heat treatment furnace. The thermal cycle between layers can also effectively eliminate some residual stress and tissue defects, and improve the mechanical properties and crack resistance of the weld. This welding method not only improves the quality of welding, but also improves production efficiency and saves costs.

[0033] 2. In the present invention, positioning welding is used before welding to position the two steel pipe segments to avoid displacement in subsequent welding. At the same time, during the welding process, the welding robot welds the welds of the steel pipe segments to form an initial melting area to facilitate subsequent welding. In the process of establishing the initial melting area, the robot cooperates with the filler robot. For larger welds, the filler robot automatically fills the welding rod at the weld to ensure normal welding. In addition, during the subsequent formal welding, mechanical vibration is applied to the welding area through an ultrasonic vibration tool and transmitted to the welding area; the frequency of the ultrasonic wave is above 20kHz, which causes a small displacement during the welding process, promotes the mixing and solidification of the molten metal, helps to eliminate pores, refine the grain structure, and improve the strength and toughness of the welded joint, so that the welding meets the quality requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A step diagram of a method for welding the seams of curved tunnel steel segments. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0040] In the description of the embodiments of the present invention, it should be noted that the terms "upper", "inner", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] See also Figure 1 The present invention provides a technical solution: a method for welding the seam of a curved tunnel steel pipe segment, which specifically comprises the following steps:

[0043] S1: Preparation step, precisely align the arc-shaped tunnel steel pipe segments to be welded according to the design requirements, and clean the oil and impurities at the joints;

[0044] S2: Preheating step, uniformly preheating the joint to reduce stress and cracks generated during welding;

[0045] S3: Positioning welding step, performing positioning welding at the joint to fix the position of the arc-shaped tunnel steel pipe segment to prevent displacement during subsequent welding;

[0046] S4: Formal welding step, using a welding robot to perform formal welding on the joint. The formal welding adopts a multi-layer and multi-pass welding method. After each welding step or layer is completed, local heat treatment is performed to eliminate welding stress and improve the microstructure;

[0047] S5: Post-weld heat treatment step, after all welding layers are completed, the final overall heat treatment is carried out to further eliminate residual stress and improve the microstructure of the weld and heat-affected zone;

[0048] S6: Inspection and correction step: after welding, the joints are inspected and any defects found are corrected in time;

[0049] S7: Data upload record, upload all parameters in the welding record and detailed data of heat treatment to the system, including holding temperature, holding time, heating rate, and cooling rate, to facilitate subsequent quality control and traceability.

[0050] The preheating temperature in S2 is 50-200°C.

[0051] The tack welding in S2 and the formal welding in S3 use the same welding materials and welding process.

[0052] The inspection in S6 adopts ultrasonic inspection or X-ray inspection.

[0053] The height of each weld seam in S4 is 3-5 mm.

[0054] A filling robot is arranged on one side of the welding robot, and the filling robot is used to fill the places with large gaps at the joints to achieve uniform welding at the joints.

[0055] The welding robot in S4 uses a laser welding system to weld the joints of the steel pipe segments before formal welding, thereby creating an initial melting area at the joints to facilitate subsequent welding.

[0056] At the same time or after laser welding, an ultrasonic vibration tool is used to apply mechanical vibration to the welding area. The frequency of the ultrasonic wave is above 20kHz, which produces tiny displacements, promotes the mixing and solidification of the molten metal, eliminates pores, refines the grain structure, and improves the strength and toughness of the weld joint.

[0057] Working principle: The position of the weld is divided into multiple welding layers, and each layer is further divided into multiple welding positions. The height of each weld is 3-5mm, and the width of each weld is kept within the design requirements. After each weld is completed, local heat treatment is performed to eliminate the stress generated by the weld and improve the microstructure. Local heat treatment can be performed using a heating blanket, induction heating or a small heat treatment furnace. The interlayer thermal cycle can also effectively eliminate some residual stress and tissue defects, and improve the mechanical properties and crack resistance of the weld. This welding method not only improves the quality of welding, but also improves production efficiency and saves costs. In addition, positioning welding is used before welding to position the two steel pipe segments to avoid displacement in subsequent welding. At the same time, during the welding process, the welding robot welds the weld of the steel pipe segment to form an initial melting area, which is convenient for subsequent welding. In the process of establishing the initial melting area, it cooperates with the filler robot. For larger welds, the filler robot automatically fills the welding rod at the weld to ensure that it can be welded normally. In addition, during the subsequent formal welding, mechanical vibration is applied to the welding area through an ultrasonic vibration tool and transmitted to the welding area. The frequency of ultrasound is above 20kHz, which causes tiny displacements during the welding process, promotes the mixing and solidification of the molten metal, helps eliminate pores, refines the grain structure, and improves the strength and toughness of the welded joint, so that the welding meets quality requirements.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for welding the seams of steel pipe segments in curved tunnels. It is characterized in that The specific steps include: S1: Preparation step, precisely align the arc-shaped tunnel steel pipe segments to be welded according to the design requirements, and clean the oil and impurities at the joints; S2: Preheating step, uniformly preheating the joint to reduce stress and cracks generated during welding; S3: Positioning welding step, performing positioning welding at the joint to fix the position of the arc-shaped tunnel steel pipe segment to prevent displacement during subsequent welding; S4: Formal welding step, using a welding robot to perform formal welding on the joint. The formal welding adopts a multi-layer and multi-pass welding method. After each welding step or layer is completed, local heat treatment is performed to eliminate welding stress and improve the microstructure; S5: Post-weld heat treatment step, after all welding layers are completed, the final overall heat treatment is carried out to further eliminate residual stress and improve the microstructure of the weld and heat-affected zone; S6: Inspection and correction step. After welding is completed, the joints are inspected and any defects found are corrected in a timely manner. S7: Data upload record, upload all parameters in the welding record and detailed data of heat treatment to the system, including holding temperature, holding time, heating rate, and cooling rate, to facilitate subsequent quality control and traceability.

2. According to claim 1, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that The preheating temperature in S2 is 50-200°C.

3. According to claim 2, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that The positioning welding in S2 and the formal welding in S3 use the same welding materials and welding process.

4. According to claim 1, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that The inspection in S6 adopts ultrasonic inspection or X-ray inspection.

5. According to claim 1, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that The height of each weld seam in S4 is 3-5 mm.

6. According to claim 1, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that A filling robot is arranged on one side of the welding robot, and the filling robot is used to fill the places with large gaps at the joints to achieve uniform welding at the joints.

7. According to claim 1, a method for welding seams of steel pipe segments for arc tunnels, It is characterized in that The welding robot in S4 uses a laser welding system to weld the joints of the steel pipe segments before formal welding, thereby creating an initial melting area at the joints to facilitate subsequent welding.

8. A method for welding seams of steel pipe segments for arc-shaped tunnels according to claim 7, It is characterized in that At the same time or after laser welding, an ultrasonic vibration tool is used to apply mechanical vibration to the welding area, and the frequency of the ultrasonic wave is above 20kHz.

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