Rolled plate welding process for steel tower drum

Abstract

The invention discloses a rolled plate welding process for a steel tower drum, and relates to the technical field of wind power tower drum rolled plate welding processes, and the process comprises the steps of steel plate pretreatment, intelligent plate rolling, gradient groove processing, segmented temperature control welding, pulse stress relief treatment and the like. The surface of a steel plate is cleaned by adopting a laser cleaning technology, the quality of the steel plate is ensured by combining eddy current detection and the like, the radian deviation of the intelligent rolled plate is corrected in real time through a plate rolling machine with an automatic aligning function and three-dimensional scanning, a composite structure of a 45-degree main groove and a 15-degree auxiliary groove is formed through gradient groove processing, and the size of a truncated edge is adaptively adjusted; the sectional temperature control welding adopts double-wire gas metal arc welding, temperature, current and voltage are controlled in a preheating section, a penetration section and a slow cooling section, residual stress is quickly released through pulse current in pulse stress relief treatment, and the process effectively solves the problems of large welding deformation, low welding efficiency, long stress relief treatment time and the like in large-scale tower drum manufacturing. And the welding quality and the production efficiency are both improved.

Description

Technical Field

[0001] This invention relates to the field of wind turbine tower plate welding technology, specifically a steel tower plate welding process. Background Technology

[0002] While existing steel tower welding processes can meet basic production needs, they still have the following shortcomings in the manufacture of large-scale towers: uneven temperature distribution during welding leads to excessive deformation; traditional single-wire welding has limited efficiency and produces coarse weld metal grains; stress relief treatment is time-consuming, affecting production cycle time. To address these issues, this invention achieves a dual improvement in welding quality and production efficiency through multiple technological innovations. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a steel tower roll welding process to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the core of this invention lies in providing a steel tower roll welding process, the specific technical solution of which is as follows:

[0005] Laser cleaning pretreatment: Compared with traditional sandblasting, laser cleaning can achieve non-contact cleaning, avoid damage to the steel plate surface, and improve cleaning efficiency by more than 30%. Eddy current testing can detect surface cracks with a depth of more than 0.1mm. Combined with conventional mechanical property testing (tensile strength ≥500MPa, impact energy ≥40J), it ensures zero defects in raw material quality.

[0006] The laser cleaning technology uses a fiber laser cleaning device with a wavelength of 1064nm, a power of 500W, and a scanning speed of 2m / min. After cleaning, the surface roughness of the steel plate is Ra≤1.6μm. The eddy current detection technology uses a high-frequency eddy current detector with a frequency of 50kHz, which can identify surface defects such as cracks and inclusions with a depth ≥0.1mm. The mechanical properties of the steel plate must meet the requirements of tensile strength ≥500MPa, impact energy ≥40J at -20℃, and carbon content ≤0.2% and manganese content 1.2%-1.6% in the chemical composition.

[0007] Intelligent plate rolling system: The plate rolling machine is equipped with a six-axis linkage self-aligning mechanism. The industrial camera captures the edge position of the steel plate in real time and automatically compensates for deviation errors during the rolling process. The three-dimensional laser scanner collects 1,000 data points per second to form a real-time curvature curve. When the deviation from the theoretical value exceeds 0.5mm, the rolling pressure is automatically corrected to ensure that the rolling accuracy reaches ±1mm.

[0008] The plate rolling machine with automatic self-aligning function is a six-axis linkage plate rolling machine with an initial pressure of 15MPa and a sampling frequency of 1000 points / second for the three-dimensional laser scanner. When the curvature deviation exceeds 0.5mm, the plate rolling machine pressure is automatically adjusted within the range of ±1MPa.

[0009] Composite bevel design: A 45° main bevel ensures penetration depth, while a 15° secondary bevel guides weld metal flow and reduces incomplete fusion defects. The blunt edge size is dynamically adjusted according to the steel plate thickness, such as a 1.2mm blunt edge for a 20mm thick steel plate, combined with a 1.5-2.5mm assembly gap to create the optimal flow pattern of the molten pool.

[0010] The gradient beveling process uses a CNC plasma cutting machine with a cutting current of 300A. The main beveling depth is 15mm for 45° and the secondary beveling depth is 3mm for 15°. The beveling alignment error is ≤0.5mm.

[0011] Segmented temperature-controlled welding technology: Helium in the ternary shielding gas can increase the heat input of the arc and reduce spatter by more than 30%. Dual-wire welding increases the deposition efficiency by 50%. The main wire is responsible for penetrating the root, and the auxiliary wire fills the middle layer. The segmented temperature control is fed back in real time by an infrared thermometer. The preheating section reduces welding stress, the penetration section ensures penetration, and the slow cooling section refines the grains, so that the hardness fluctuation of the weld is controlled within ±15HB.

[0012] In dual-wire gas metal arc welding, both the main wire and the auxiliary wire are ER50-6 welding wire, the shielding gas flow rate is 25L / min, the temperature is monitored in real time by an infrared thermometer with a temperature measurement accuracy of ±5℃, the welding speed of the preheating section of the segmented temperature-controlled welding is 0.5m / min, the welding speed of the penetration section is 0.8m / min and the penetration depth is ≥ the thickness of the steel plate, and the welding speed of the slow cooling section is 0.6m / min.

[0013] Pulse stress relief innovation: Traditional heat treatment takes several hours, but this process uses high-frequency pulsed current to induce plastic deformation in the weld area, quickly releasing residual stress. After treatment, ultrasonic impact is used to further strengthen the weld surface, increasing fatigue strength by 20%-30% and shortening the overall production cycle by 25%.

[0014] Pulse stress relief treatment must be carried out within 30 minutes after welding, and the residual stress after treatment should be ≤150MPa. Subsequent non-destructive testing will be carried out using UT (ultrasonic testing) and MT (magnetic particle testing). Corrosion protection treatment is carried out by Sa2.5 grade sandblasting to remove rust, followed by spraying an epoxy primer with a dry film thickness of 80μm.

[0015] In summary, the present invention has the following main advantages: By combining laser cleaning and eddy current detection, the present invention achieves efficient cleaning and precise quality control of steel plate surfaces, ensuring defect-free raw materials and laying a solid foundation for subsequent welding. The intelligent plate rolling system, with its six-axis linkage and three-dimensional laser scanning for real-time correction, ensures plate rolling accuracy of ±1mm, solving the problem of large curvature deviation in traditional plate rolling. The composite bevel design, combined with segmented temperature-controlled welding technology, ensures penetration depth with a 45° main bevel and reduces incomplete fusion defects with a 15° secondary bevel. Dual-wire welding and ternary shielding gas improve deposition efficiency by more than 50%. Segmented temperature control refines grain size, resulting in small fluctuations in weld hardness and stable quality. Pulse stress relief treatment significantly shortens the time compared to traditional heat treatment, quickly releasing residual stress. Combined with non-destructive testing and anti-corrosion treatment, the invention significantly improves weld reliability and overall tower performance, while shortening the production cycle by 25%, balancing quality and efficiency. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the overall process of this invention.

[0017] Figure 2 This is a schematic diagram of the beveling structure of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] The embodiments of the present invention will now be described.

[0020] Example 1

[0021] like Figure 1-2 As shown, this embodiment takes the welding of a 20mm thick, 4m diameter wind turbine steel tower coil as an example to illustrate the process flow in detail:

[0022] Steel plate pretreatment

[0023] Laser cleaning: A fiber laser cleaning device with a wavelength of 1064nm is used to scan and clean the surface of the steel plate. The power is 500W and the scanning speed is 2m / min. The surface oil, oxide scale and impurities are removed. After cleaning, the surface roughness Ra≤1.6μm.

[0024] Quality Inspection:

[0025] Eddy current testing: A high-frequency eddy current tester with a frequency of 50kHz is used to perform a full scan of the steel plate surface to identify defects such as cracks and inclusions with a depth ≥0.1mm.

[0026] Mechanical property testing: Samples are taken for tensile testing to ensure tensile strength ≥ 500 MPa and impact testing at -20℃ with impact energy ≥ 40 J to ensure mechanical properties meet standards;

[0027] Chemical composition analysis: Spectrometer testing ensures that the carbon content of the steel plate is ≤0.2% and the manganese content is 1.2%-1.6%, meeting weldability requirements;

[0028] Intelligent roll plate

[0029] Equipment and parameter settings: Feed the pre-treated steel plate, which is 12m×2m in size, into the six-axis linkage plate rolling machine. Input the parameters of 4m tower diameter. The system will automatically generate the rolling path, with an initial pressure of 15MPa and a rolling speed of 1.0m / min.

[0030] Real-time correction: During the plate rolling process, a 3D laser scanner with a sampling frequency of 1000 points / second collects the arc data of the steel plate in real time and compares it with the theoretical arc (curvature radius 2m). When the deviation exceeds 0.5mm, the plate rolling machine automatically adjusts the pressure (fluctuation range ±1MPa) to correct the arc deviation, and finally controls the rolling accuracy within ±1mm.

[0031] Gradient beveling

[0032] Plasma cutting: A CNC plasma cutting machine (cutting current 300A) is used to bevel the interface of the rolled plate to form a composite structure.

[0033] Main bevel: 45°, depth 15mm;

[0034] Secondary bevel: 15°, depth 3mm;

[0035] Blunt edge: set at 6% of the steel plate thickness, i.e., 1.2mm;

[0036] Assembly gap: 2.0mm, ensuring bevel alignment error ≤0.5mm;

[0037] Segmented temperature-controlled welding

[0038] Welding equipment and materials: A dual-wire gas metal arc welding machine is used. The main wire is ER50-6 welding wire with a diameter of 1.2mm and the auxiliary wire is ER50-6 welding wire with a diameter of 1.0mm. The shielding gas is a mixture of argon (85%), carbon dioxide (12%) and helium (3%) (flow rate 25L / min).

[0039] Segmented welding control:

[0040] Preheating section: The bevel area is preheated to 100℃ by a medium frequency induction heating device, with a welding current of 230A, a voltage of 28V, and a welding speed of 0.5m / min to ensure uniform temperature before welding.

[0041] Penetration section: Temperature controlled at 220℃, main wire current 310A, auxiliary wire current 280A, voltage 32V, welding speed 0.8m / min, to ensure complete penetration of the root (penetration depth ≥20mm);

[0042] Slow cooling section: Temperature drops to 160℃, current 210A, voltage 26V, welding speed 0.6m / min, slow cooling refines weld grains;

[0043] Real-time monitoring: An infrared thermometer (accuracy ±5℃) monitors the temperature of the welding area throughout the process, ensuring that the temperature remains stable within the set range at each stage;

[0044] Pulse stress relief treatment

[0045] Pulse treatment: Within 30 minutes after welding, the weld area is treated with a pulse current device. The parameters are set as follows: pulse frequency 80Hz, peak current 900A, duration 12s. The residual stress is released through the thermal effect of the current (the residual stress after treatment is ≤150MPa).

[0046] Follow-up processing:

[0047] Non-destructive testing: Perform UT (ultrasonic testing) and MT (magnetic particle testing) on ​​the welds to ensure there are no defects such as internal cracks or lack of fusion;

[0048] Corrosion protection: After sandblasting to remove rust (Sa2.5 grade), apply epoxy primer (dry film thickness 80μm) to complete the protection after tower welding;

[0049] This embodiment is applicable to the rolling plate welding of large wind turbine steel towers. Through precise control of the entire process, it balances welding quality and production efficiency, meeting the high reliability requirements of wind power equipment.

[0050] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A steel tower tube plate rolling and welding process, characterized in that, Includes the following steps: S1: Steel plate pretreatment: Laser cleaning technology is used to clean the surface of the steel plate to remove oil, rust and impurities. At the same time, eddy current testing technology is used to detect surface defects of the steel plate. Combined with mechanical property and chemical composition testing, the quality of the steel plate is ensured. S2: Intelligent plate rolling: The pre-treated steel plate is fed into a plate rolling machine with automatic self-aligning function. The rolling path is automatically generated according to the tower diameter parameters. During the rolling process, the curvature deviation is corrected in real time through three-dimensional scanning. The rolling speed adopts a dynamic adjustment mode of 0.8-1.2m / min. S3: Gradient beveling: Plasma cutting technology is used to bevele the interface of the rolled plate to form a composite structure of 45° main bevel + 15° secondary bevel. The blunt edge size is adaptively adjusted according to 5%-8% of the steel plate thickness, and the assembly gap is controlled at 1.5-2.5mm. S4: Segmented temperature-controlled welding: Dual-wire gas metal arc welding is adopted. The main wire and auxiliary wire are selected with diameters of 1.2mm and 1.0mm respectively. The shielding gas is a ternary gas mixture of argon (85%), carbon dioxide (12%) and helium (3%). The welding process is divided into three temperature ranges: preheating (80-120℃), penetration (200-250℃), and slow cooling (150-180℃). The corresponding currents are 220-250A, 300-320A, and 200-220A respectively. The voltage is dynamically matched with the current. S5: Pulse stress relief treatment: Immediately after welding, stress relief treatment is performed using pulsed current with a pulse frequency of 50-100Hz, a peak current of 800-1000A, and a duration of 10-15s. Then, routine non-destructive testing and anti-corrosion treatment are carried out.

2. The steel tower tube rolling and welding process according to claim 1, characterized in that: The laser cleaning technology uses a fiber laser cleaning device with a wavelength of 1064nm, a power of 500W, a scanning speed of 2m / min, and the surface roughness of the steel plate after cleaning is Ra≤1.6μm.

3. The steel tower tube rolling and welding process according to claim 1, characterized in that: The eddy current testing technology uses a high-frequency eddy current tester with a frequency of 50kHz, which can identify surface defects such as cracks and inclusions with a depth of ≥0.1mm. The mechanical properties of the steel plate must meet the requirements of tensile strength ≥500MPa, impact energy ≥40J at -20℃, and carbon content ≤0.2% and manganese content 1.2%-1.6% in the chemical composition.

4. The steel tower tube rolling and welding process according to claim 1, characterized in that: The plate rolling machine with automatic self-alignment function is a six-axis linkage plate rolling machine with an initial pressure of 15MPa and a sampling frequency of 1000 points / second for the three-dimensional laser scanner. When the curvature deviation exceeds 0.5mm, the pressure of the plate rolling machine is automatically adjusted within the range of ±1MPa.

5. The steel tower tube rolling and welding process according to claim 1, characterized in that: The gradient beveling process is performed using a CNC plasma cutting machine with a cutting current of 300A. The main beveling depth is 15mm at 45°, the secondary beveling depth is 3mm at 15°, and the beveling alignment error is ≤0.5mm.

6. The steel tower tube rolling and welding process according to claim 1, characterized in that: In the dual-wire gas metal arc welding, both the main wire and the auxiliary wire are ER50-6 welding wires, the shielding gas flow rate is 25L / min, and the temperature is monitored in real time by an infrared thermometer with a temperature measurement accuracy of ±5℃.

7. The steel tower tube rolling and welding process according to claim 1, characterized in that: The segmented temperature-controlled welding has a preheating section welding speed of 0.5 m / min, a penetration section welding speed of 0.8 m / min with a penetration depth ≥ steel plate thickness, and a slow cooling section welding speed of 0.6 m / min.

8. The steel tower tube rolling and welding process according to claim 1, characterized in that: The pulse stress relief treatment must be carried out within 30 minutes after welding, and the residual stress after treatment should be ≤150MPa. Subsequent non-destructive testing will be carried out using UT (ultrasonic testing) and MT (magnetic particle testing). The anti-corrosion treatment is to spray an epoxy primer with a dry film thickness of 80μm after rust removal by Sa2.5 grade sandblasting.

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