Low-temperature welding process for steel frame steel structure

Abstract

The application discloses a kind of steel frame steel structure low-temperature welding process, it is related to the welding technical field under the low-temperature environment of metal structural member in building construction, comprising the following steps: welding preparation: welding material selection and the surface cleaning treatment of welding material place;Welding operation: in low-temperature environment, the welding area of welding material is set preheating temperature, and welding parameter is optimized;Slow cooling treatment after welding: after welding material is placed slow cooling environment, and slow cooling temperature and slow cooling duration are controlled;The application is optimized by welding material and process parameter, reduces the stress concentration caused by temperature difference in welding process, saves energy consumption under the premise of guaranteeing engineering quality, reduces production cost;Through multilevel slow cooling measures, effectively control the organizational transformation behavior in weld cooling process, promote the development of construction industry in cold region, enhance the safety and stability of building under extreme weather conditions.

Description

Technical Field

[0001] This invention relates to the field of welding technology for metal structural components in low-temperature environments during building construction, and specifically to a low-temperature welding process for steel frame structures. Background Technology

[0002] With the rapid development of the construction industry and the continuous advancement of infrastructure construction, steel frame and steel structure have been widely used in modern building engineering. Traditional welding technology can effectively ensure weld quality and meet engineering requirements in room temperature and warm environments. However, as construction projects gradually expand to high-altitude and cold regions, welding problems in low-temperature environments are becoming increasingly prominent, becoming a significant factor restricting project quality and safety. Low-temperature environments not only significantly affect the mechanical properties of welding materials but also easily lead to quality problems such as weld cracks and thermal stress concentration, thereby reducing the safety and service life of buildings.

[0003] Currently, to address the challenges of welding under low-temperature conditions, the industry primarily employs methods such as preheating, rapid cooling, and the use of special alloy materials. Preheating reduces the risk of cold cracking by increasing the workpiece temperature before welding, but this method is time-consuming and inefficient, making it unsuitable for large-scale construction. Rapid cooling attempts to avoid thermal stress concentration by rapidly reducing the temperature gradient around the weld, but this often leads to increased hardness and decreased toughness in the weld area, further impacting the overall performance of the welded structure. While using special alloy materials can improve the low-temperature resistance of the weld to some extent, their high cost limits their practical application. Furthermore, existing technologies lack sufficient control precision during preheating and cooling processes, easily introducing additional defects, and the range of selectable high-performance alloy materials is limited, making it difficult to fully meet diverse engineering needs.

[0004] In order to comprehensively consider key aspects such as the selection of welding materials, pre-weld preparation, precise control of the welding process, and post-weld treatment, so as to minimize the impact of low temperature environment on welding quality, while taking into account construction efficiency and cost control, there is an urgent need for an economical, efficient and reliable low temperature welding process.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a low-temperature welding process for steel frame structures. This invention addresses the problems in the background art by focusing on the selection of welding materials, pre-weld preparation, precise control of the welding process, and post-weld treatment during the low-temperature welding of steel frame structures.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a low-temperature welding process for steel frame structures, comprising the following steps:

[0008] S1. Pre-welding preparation: Selection of welding materials and surface cleaning of the welding material area;

[0009] S2. Welding operation: In a low-temperature environment, set the preheating temperature for the welding area of ​​the welding material and optimize the welding parameters;

[0010] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment and control the slow cooling temperature and duration; then cover the weld area with a double-layer composite insulation material. The weld cooling rate is dynamically adjusted according to the ambient temperature, and the cooling rate does not exceed 8℃ / min. The time to cool to ambient temperature is... The insulation material should not be removed until 72 hours after welding is completed;

[0011] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0012] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0013] Optionally, the welding material is selected as a high-nickel content stainless steel welding electrode.

[0014] Optionally, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area.

[0015] Optionally, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0016] Optionally, the weld inspection tool includes a weld appearance visual detector, an ultrasonic and X-ray scanner, to perform flaw detection on the weld after welding.

[0017] Optionally, the temperature of the low-temperature environment is -20℃ to -40℃.

[0018] Optionally, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0019] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0020] Optionally, the preheating temperature is in the range of 50℃-150℃.

[0021] Optionally, the welding parameters include welding speed and welding current intensity, and the welding speed... 40mm / min, welding current intensity in the range of 80A-160A.

[0022] Optionally, the slow cooling temperature is controlled within the range of 150℃-200℃, and the slow cooling duration is... .

[0023] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0024] This invention optimizes welding materials and process parameters to reduce stress concentration caused by temperature differences during welding, saving energy and reducing production costs while ensuring project quality. Through multi-stage slow cooling measures, it effectively regulates the microstructure transformation behavior during weld cooling, promoting the development of the construction industry in cold regions and enhancing the safety and stability of buildings under extreme weather conditions. Furthermore, by introducing composite insulation materials and a phased slow cooling strategy, it achieves effective control over the weld cooling rate, significantly improving welding quality, greatly increasing the success rate of steel frame and steel structure welding under low-temperature conditions, and effectively reducing problems such as cracks caused by excessively low temperatures. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0026] Figure 1 This is a flowchart of a low-temperature welding process for steel frame structures according to the present invention. Detailed Implementation

[0027] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0028] Example 1

[0029] This invention provides, for example Figure 1 The low-temperature welding process for steel frame structures shown includes the following steps:

[0030] S1. Pre-welding preparation: Selection of welding materials and surface cleaning of the welding material area;

[0031] S2. Welding operation: In a low-temperature environment, set the preheating temperature for the welding area of ​​the welding material and optimize the welding parameters;

[0032] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment and control the slow cooling temperature and duration; then cover the weld area with a double-layer composite insulation material. The weld cooling rate is dynamically adjusted according to the ambient temperature, and the cooling rate does not exceed 8℃ / min. The time to cool to ambient temperature is... The insulation material should not be removed until 72 hours after welding is completed;

[0033] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0034] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0035] Specifically, the welding material selected is high-nickel content stainless steel welding rod.

[0036] Specifically, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area to ensure that the contact surface of the materials to be welded is clean.

[0037] Specifically, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0038] Specifically, the weld inspection tool includes a weld appearance visual detector, an ultrasonic scanner, and a radiographic scanner, which are used to perform flaw detection on the weld after welding.

[0039] Specifically, the low-temperature environment is -20℃ to -40℃ and is used for steel structure welding construction under extreme low-temperature conditions.

[0040] Specifically, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0041] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0042] Specifically, the preheating temperature is in the range of 50℃-150℃.

[0043] Specifically, the welding parameters include welding speed and welding current intensity, and the welding speed... 40mm / min, welding current intensity in the range of 80A-160A.

[0044] Specifically, the slow cooling temperature is controlled within the range of 150℃-200℃, and the slow cooling duration is... .

[0045] Example 2

[0046] A low-temperature welding process for steel frame structures includes the following steps:

[0047] S1. Pre-welding preparation: Select high-nickel stainless steel welding rods as the welding material, and perform mechanical grinding and chemical cleaning on the surface of the welding material.

[0048] S2. Welding operation: In a low temperature environment of -20℃, set the preheating temperature for the welding area of ​​the welding material, and the preheating temperature range is 150℃. Optimize the welding parameters and limit the welding speed to 40mm / min and the welding current intensity to 160A.

[0049] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment, controlling the slow cooling temperature and duration. The slow cooling temperature should be controlled within the range of 150℃, and the slow cooling duration should be [not specified]. Subsequently, a double-layer composite insulation material consisting of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam was used to cover the weld area. The cooling rate of the weld was dynamically adjusted according to the ambient temperature, and the cooling rate did not exceed 8℃ / min. The time to cool to the ambient temperature was... The insulation material should not be removed until 72 hours after welding is completed;

[0050] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools such as visual detectors, ultrasonic and X-ray scanners to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0051] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0052] Specifically, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area to ensure that the contact surface of the materials to be welded is clean.

[0053] Specifically, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0054] Specifically, the weld inspection tool includes a weld appearance visual detector, an ultrasonic scanner, and a radiographic scanner, which are used to perform flaw detection on the weld after welding.

[0055] Specifically, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0056] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0057] Example 3

[0058] A low-temperature welding process for steel frame structures includes the following steps:

[0059] S1. Pre-welding preparation: Select high-nickel stainless steel welding rods as the welding material, and perform mechanical grinding and chemical cleaning on the surface of the welding material.

[0060] S2. Welding operation: In a low temperature environment of -40℃, set the preheating temperature for the welding area of ​​the welding material, and the preheating temperature range is 50℃. Optimize the welding parameters and limit the welding speed to 20mm / min and the welding current intensity to 80A.

[0061] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment, controlling the slow cooling temperature and duration. The slow cooling temperature should be controlled within the range of 200℃, and the slow cooling duration should be [not specified]. Subsequently, a double-layer composite insulation material consisting of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam was used to cover the weld area. The cooling rate of the weld was dynamically adjusted according to the ambient temperature, and the cooling rate did not exceed 8℃ / min. The time to cool to the ambient temperature was... The insulation material should not be removed until 72 hours after welding is completed;

[0062] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools such as visual detectors, ultrasonic and X-ray scanners to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0063] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0064] Specifically, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area to ensure that the contact surface of the materials to be welded is clean.

[0065] Specifically, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0066] Specifically, the weld inspection tool includes a weld appearance visual detector, an ultrasonic scanner, and a radiographic scanner, which are used to perform flaw detection on the weld after welding.

[0067] Specifically, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0068] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0069] Example 4

[0070] A low-temperature welding process for steel frame structures includes the following steps:

[0071] S1. Pre-welding preparation: Select high-nickel stainless steel welding rods as the welding material, and perform mechanical grinding and chemical cleaning on the surface of the welding material.

[0072] S2. Welding operation: In a low temperature environment of -40℃, set the preheating temperature for the welding area of ​​the welding material, and the preheating temperature range is 150℃. Optimize the welding parameters and limit the welding speed to 20mm / min and the welding current intensity to 80A.

[0073] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment, controlling the slow cooling temperature and duration. The slow cooling temperature should be controlled within the range of 150℃, and the slow cooling duration should be [not specified]. Subsequently, a double-layer composite insulation material consisting of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam was used to cover the weld area. The cooling rate of the weld was dynamically adjusted according to the ambient temperature, and the cooling rate did not exceed 8℃ / min. The time to cool to the ambient temperature was... The insulation material should not be removed until 72 hours after welding is completed;

[0074] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools such as visual detectors, ultrasonic and X-ray scanners to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0075] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0076] Specifically, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area to ensure that the contact surface of the materials to be welded is clean.

[0077] Specifically, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0078] Specifically, the weld inspection tool includes a weld appearance visual detector, an ultrasonic scanner, and a radiographic scanner, which are used to perform flaw detection on the weld after welding.

[0079] Specifically, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0080] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0081] Example 5

[0082] A low-temperature welding process for steel frame structures includes the following steps:

[0083] S1. Pre-welding preparation: Select high-nickel stainless steel welding rods as the welding material, and perform mechanical grinding and chemical cleaning on the surface of the welding material.

[0084] S2. Welding operation: In a low temperature environment of -30℃, set the preheating temperature for the welding area of ​​the welding material, and the preheating temperature range is 100℃. Optimize the welding parameters and limit the welding speed to 30mm / min and the welding current intensity to 120A.

[0085] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment, controlling the slow cooling temperature and duration. The slow cooling temperature should be controlled within the range of 180℃, and the slow cooling duration should be [not specified]. Subsequently, a double-layer composite insulation material consisting of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam was used to cover the weld area. The cooling rate of the weld was dynamically adjusted according to the ambient temperature, and the cooling rate did not exceed 8℃ / min. The time to cool to the ambient temperature was... The insulation material should not be removed until 72 hours after welding is completed;

[0086] S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools such as visual detectors, ultrasonic and X-ray scanners to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects.

[0087] S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

[0088] Specifically, the surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area to ensure that the contact surface of the materials to be welded is clean.

[0089] Specifically, the double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

[0090] Specifically, the weld inspection tool includes a weld appearance visual detector, an ultrasonic scanner, and a radiographic scanner, which are used to perform flaw detection on the weld after welding.

[0091] Specifically, the dynamic adjustment of the weld cooling rate satisfies the following conditions:

[0092] The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

[0093] Comparative Example

[0094] A low-temperature welding process for steel frame structures includes the following steps:

[0095] S1. Pre-welding preparation: Select low-hydrogen welding rods as the welding material and clean the surface of the welding material.

[0096] S2. Welding operation: In a low temperature environment of -15℃ to -35℃, set the preheating temperature for the welding area of ​​the welding material, and the preheating temperature range is 350℃-380℃, and the preheating time is 1.5h-2h.

[0097] S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling and heat preservation box, and control the slow cooling temperature in the range of 110℃-120℃; then cover the weld area with heat preservation cotton, and remove the heat preservation cotton on the second day after the welding is completed.

[0098] S4. Weld quality inspection and defect repair: When surface defects such as porosity, slag inclusion, weld beads, and excessive weld reinforcement exceed the standard, they should be removed by grinding with a grinding wheel or by welding repair. For defects such as insufficient weld size, local missing material, depression, low depression, undercut, incomplete arc crater filling, or poor transition of fillet weld, welding repair should be carried out, followed by grinding repair.

[0099] Table: A comparative analysis of the welding effect indicators of welding materials in Examples 2-5 and the comparative examples is as follows:

[0100] Case Example 2 Example 3 Example 4 Example 5 Comparative Example Crack resistance Low cold crack sensitivity index Low cold crack sensitivity index Low cold crack sensitivity index Low cold crack sensitivity index Low cold crack sensitivity index Cooling rate quick Faster quick quick Faster weld toughness ISO 148-1 Charpy impact test: high absorption capacity ISO 148-1 Charpy impact test: high absorption capacity ISO 148-1 Charpy impact test: high absorption capacity ISO 148-1 Charpy impact test: high absorption capacity ISO 148-1 Charpy impact test has a relatively high absorption capacity. Welding quality High austenite grain size High austenite grain size High austenite grain size High austenite grain size High austenite grain size

[0101] In summary, through comparative analysis of welding performance indicators such as crack resistance, cooling rate, weld toughness, and welding quality, the low-temperature welding process for this steel frame structure, by comprehensively considering key aspects such as the selection of welding materials, pre-weld preparation, precise control of the welding process, and post-weld treatment, minimizes the impact of the low-temperature environment on welding quality, effectively controls the weld cooling rate, and significantly improves welding quality.

[0102] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0103] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0104] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0106] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A low-temperature welding process for steel frame structures, characterized in that, Includes the following steps: S1. Pre-welding preparation: Selection of welding materials and surface cleaning of the welding material area; S2. Welding operation: In a low-temperature environment, set the preheating temperature for the welding area of ​​the welding material and optimize the welding parameters; S3. Post-weld slow cooling treatment: Place the welded material in a slow cooling environment and control the slow cooling temperature and duration; then cover the weld area with a double-layer composite insulation material. The weld cooling rate is dynamically adjusted according to the ambient temperature, and the cooling rate does not exceed 8℃ / min. The time to cool to ambient temperature is... The insulation material should not be removed until 72 hours after welding is completed; S4. Weld quality inspection and defect repair: Weld quality inspection is carried out using weld inspection tools to identify defects such as porosity, slag inclusions or cracks in the weld, and to repair the defects. S5. Welding tool maintenance: Welding tools should be maintained and serviced regularly every 100 hours according to the welding working time to extend their service life.

2. The low-temperature welding process for steel frame structures according to claim 1, characterized in that, The welding material selected is high-nickel stainless steel welding rod.

3. The low-temperature welding process for steel frame structures according to claim 2, characterized in that, The surface cleaning treatment of the welding material includes mechanical grinding and chemical cleaning to remove rust, oil and contaminants from the welding area.

4. The low-temperature welding process for steel frame structures according to claim 3, characterized in that, The double-layer composite insulation material consists of an inner layer of high-temperature resistant ceramic fiber and an outer layer of heat-insulating foam.

5. The low-temperature welding process for steel frame structures according to claim 4, characterized in that, The weld inspection tool includes a weld appearance visual detector, ultrasonic and X-ray scanners, which are used to perform flaw detection on the weld after welding.

6. The low-temperature welding process for steel frame structures according to claim 5, characterized in that, The temperature of the low-temperature environment is -20℃ to -40℃.

7. The low-temperature welding process for steel frame structures according to claim 6, characterized in that, The dynamic adjustment of the weld cooling rate must meet the following conditions: The cooling rate control method based on heat conduction and phase transformation kinetics dynamically adjusts the cooling rate of the weld. The calculation formula for this cooling rate control method is as follows: ,and In the formula, This is represented as the weld seam in time. The temperature at that time This refers to the temperature of a low-temperature environment. This represents the highest temperature of the weld. Represented as a natural exponential function, Expressed as the cooling rate constant, It is represented as a time variable.

8. The low-temperature welding process for steel frame structures according to claim 7, characterized in that, The preheating temperature is in the range of 50℃-150℃.

9. The low-temperature welding process for steel frame structures according to claim 8, characterized in that, The welding parameters include welding speed and welding current intensity, and the welding speed... 40mm / min, welding current intensity in the range of 80A-160A.

10. The low-temperature welding process for steel frame structures according to claim 9, characterized in that, The slow cooling temperature is controlled within the range of 150℃-200℃, and the slow cooling duration is... .

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