Automatic welding method for steam turbine rotating ring

Abstract

Automatic welding method of steam turbine rotating ring. It solves the problems of manual operation, poor positioning accuracy, large welding stress and high welding defect rate in the existing steam turbine rotating ring welding process. Method: the rotating ring and the welding area are cleaned and detected; one half of the rotating ring is positioned by three points; the welding is performed, and then the temperature is uniformed; the other half of the rotating ring is fixed, welded and treated by uniform temperature; after the whole welding is completed, the tempering heat treatment and nondestructive testing are performed. The invention overcomes the problems of unstable quality and low efficiency of traditional manual welding; the automatic welding production cycle is shortened by more than 30%; the dependence on manual work is reduced; the demand for high-skilled welders is reduced, the labor intensity and risk are reduced; the quality is stable and reliable; the weld formation is consistent, the defects are significantly reduced, and the strict standards are met; it can be popularized and applied: experience is accumulated for welding of high-temperature alloy material parts, and it has the potential to be popularized to other key parts.

Description

Technical Field

[0001] This invention specifically relates to an automated welding method for turbine rotating rings. Background Technology

[0002] The rotating ring is a key component of a steam turbine, installed at both ends of the rotor. Its main functions are support, guidance, and sealing, and it withstands long-term high-temperature, high-pressure, and high-speed operating environments. It is often manufactured using high-temperature alloy materials, with hard alloy layers welded onto critical areas to improve wear resistance and corrosion resistance. The welding quality directly affects the operational safety and lifespan of the equipment. Currently, manual argon arc welding is commonly used for this process, but this method has the following significant shortcomings in practical applications:

[0003] 1. It needs to be carried out in a high-temperature environment of 300℃~350℃, which is labor-intensive and highly dependent on the welding skills;

[0004] 2. Due to human factors, welds are prone to quality defects such as cracks, insufficient penetration, and uneven formation, resulting in poor stability;

[0005] 3. Temperature control during welding is difficult to ensure interpass temperature and uniform heating, resulting in large residual stress in the weld and affecting the welding performance of the rotating ring.

[0006] 4. The overall welding efficiency is low and the product qualification rate is not high, which restricts mass production and standardization. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of excessive manual operation, poor positioning accuracy, high welding stress, and high welding defect rate in the existing steam turbine rotating ring welding process, and to provide an automated welding method for steam turbine rotating rings.

[0008] An automated welding method for turbine rotating rings is implemented through the following steps:

[0009] I. Pre-processing:

[0010] The rotating ring and welding area were cleaned, and then the welding area was inspected using PT penetrant testing to ensure that the welding conditions were up to standard.

[0011] II. Fixed:

[0012] The rotating ring has a two-half structure. During welding, one half of the rotating ring is taken first and fixed on the turntable with a pressure plate. Then, a positioning plate is used to perform three-point positioning on the inner circle of the half rotating ring.

[0013] III. Welding and Isostatic Treatment:

[0014] After the above three points are positioned, a single-layer, single-pass plasma spraying welding method is used for welding. After welding, the ring is sent to a heating furnace for homogenization treatment. Then, the other half of the rotating ring is fixed, welded, and homogenized in the same way, thus completing the overall welding of the rotating ring.

[0015] IV. Tempering heat treatment and testing:

[0016] After the overall welding of the aforementioned rotating ring is completed, the rotating ring is subjected to tempering heat treatment, and then the weld is subjected to non-destructive testing. Once the non-destructive testing is qualified, the automated welding of the turbine rotating ring is completed.

[0017] Furthermore, the standard for meeting the welding conditions described in step one is that the surface of the rotating ring base material is free of cracks and porosity defects.

[0018] Furthermore, the three-point positioning mentioned in step two involves using three positioning plates arranged along the inner circle of a half-rotation ring, with the three positioning plates located at 30°, 90°, and 150° of the inner circle, respectively.

[0019] Furthermore, the temperature equalization treatment described in step three involves maintaining the temperature at 300~350℃ for 4~5 hours.

[0020] Furthermore, the welding parameters described in step three are as follows:

[0021] The welding current is 180A, the welding speed is 70mm / min, the amount of welding powder is 23g / min, the oscillation speed is 1200mm / min, the dwell time at the left end is 0.4s, the dwell time at the right end is 0.4s, the oscillation amplitude is 17mm, the ion gas flow rate is 4L / min, the shielding gas flow rate is 25L / min, and the powder feeding gas flow rate is 3L / min.

[0022] Furthermore, in step three, both the arc initiation and arc termination during the welding process are carried out on the arc initiation and termination plates.

[0023] Furthermore, during the welding process described in step three, an infrared thermometer is used for real-time monitoring to control the interlayer temperature at 350°C. When the temperature is insufficient, flame heating is used to supplement the heating.

[0024] Furthermore, the tempering heat treatment described in step four involves holding the temperature at 650°C for 4 hours.

[0025] Furthermore, the non-destructive testing described in step four involves PT penetrant testing at the arc initiation and termination points, and UT ultrasonic testing and MT magnetic particle testing at the remaining points.

[0026] Furthermore, the criteria for passing non-destructive testing in step four are: no defects inside or on the surface of the weld, and the weld quality meets the design and usage requirements.

[0027] Advantages of this invention:

[0028] 1. Overcoming technical bottlenecks: It overcomes the problems of unstable quality and low efficiency in traditional manual welding.

[0029] 2. Significantly improved efficiency: The automated welding production cycle is shortened by more than 30%.

[0030] 3. Reduce reliance on manual labor: Reduce the demand for highly skilled welders, thereby reducing labor intensity and risks.

[0031] 4. Stable and reliable quality: The weld formation is consistent, defects are significantly reduced, and it meets strict standards.

[0032] 5. Potential for wider application: It accumulates experience in welding high-temperature alloy components and has the potential to be extended to other key components.

[0033] This invention proposes an automated welding method for turbine rotating rings, which solves the problems of excessive manual operation, poor positioning accuracy, high welding stress, and high welding defect rate in traditional manual welding of rotating rings. This method can achieve efficient and stable surfacing welding of rotating rings, reduce reliance on manual labor, improve welding quality and production efficiency, and provide a standardized solution for the manufacturing of high-temperature alloy components.

[0034] This invention has the following innovations: First, it addresses the structural characteristics of the split rotating ring by employing three-point positioning on the inner circle combined with ordinary pressure plates for fixation, achieving simple clamping and high repeatability accuracy. Second, it proposes a process scheme combining segmented welding and post-weld isothermal treatment, whereby one half of the rotating ring is welded first and then isothermal treated in the furnace before welding the other half, fundamentally reducing residual welding stress. Third, it uniformly handles arc initiation and termination issues through arc initiation and termination plates during the welding process, avoiding shrinkage cavities and arc craters in the weld. Fourth, it achieves stable control of interpass temperature through automated equipment combined with flame-assisted heating.

[0035] This invention is applicable to the automated welding of turbine rotating rings. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the welding process using a single-layer, single-pass plasma spraying method after the three-point positioning is completed in the embodiment.

[0037] Figure 2 This is a schematic diagram of the weld seam of one half of the rotating ring after welding, as shown in the embodiment.

[0038] Figure 3 This is a schematic diagram showing the assembly of the two rotating ring halves after the overall welding is completed in the embodiment. Detailed Implementation

[0039] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0040] Specific Implementation Method 1: This implementation method for automated welding of turbine rotating rings is achieved through the following steps:

[0041] I. Pre-processing:

[0042] The rotating ring and welding area were cleaned, and then the welding area was inspected using PT penetrant testing to ensure that the welding conditions were up to standard.

[0043] II. Fixed:

[0044] The rotating ring has a two-half structure. During welding, one half of the rotating ring is taken first and fixed on the turntable with a pressure plate. Then, a positioning plate is used to perform three-point positioning on the inner circle of the half rotating ring.

[0045] III. Welding and Isostatic Treatment:

[0046] After the above three points are positioned, a single-layer, single-pass plasma spraying welding method is used for welding. After welding, the ring is sent to a heating furnace for homogenization treatment. Then, the other half of the rotating ring is fixed, welded, and homogenized in the same way, thus completing the overall welding of the rotating ring.

[0047] IV. Tempering heat treatment and testing:

[0048] After the overall welding of the aforementioned rotating ring is completed, the rotating ring is subjected to tempering heat treatment, and then the weld is subjected to non-destructive testing. Once the non-destructive testing is qualified, the automated welding of the turbine rotating ring is completed.

[0049] The purpose of cleaning in step one of this embodiment is to remove oil, scale and other impurities to ensure the quality of weld formation.

[0050] In step two of this embodiment, a positioning plate is used to perform three-point positioning on the inner circle of one half of the rotating ring. The purpose is to ensure that the rotating ring and the turntable are concentric. At the same time, since the inner diameters of the two halves of the rotating ring are the same, after the welding and isothermal treatment of one half of the rotating ring are completed, the welding of the other half of the rotating ring can reuse the same three-point positioning method, thereby improving process consistency and operational convenience, and improving clamping efficiency and welding accuracy.

[0051] In step three of this embodiment, a single-layer, single-pass plasma spraying method is used to avoid welding deformation and stress concentration. First, half of the rotating ring is welded and immediately placed in a heating furnace for homogenization. This ensures that the stress in the weld and the base material of the rotating ring is fully released and alleviated. After the first half of the rotating ring has been homogenized, the other half is fixed, welded, and homogenized. This sequence ensures the overall concentricity and consistency of the microstructure and properties of the rotating ring.

[0052] Throughout the entire welding process in step three of this embodiment, it is necessary to maintain a stable electric arc and ensure that the weld bead is uniform and full to prevent problems such as slag inclusion or lack of fusion.

[0053] The purpose of the tempering heat treatment in step four of this embodiment is to eliminate residual stress, refine the weld structure, improve the overall performance of the joint, and ensure long-term stable welding quality.

[0054] The purpose of non-destructive testing in step four of this implementation method is to ensure that surface and internal defects of the weld can be effectively detected and eliminated, and to ensure that the weld quality meets the design and usage requirements.

[0055] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the standard for qualified welding conditions in step one is that the surface of the base material of the rotating ring is free of cracks and porosity defects. Other steps and parameters are the same as in Specific Implementation Method One.

[0056] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the three-point positioning in step two involves using three positioning plates arranged along the inner circle of a half-rotation ring. The three positioning plates are located at 30°, 90°, and 150° of the inner circle, respectively. Other steps and parameters are the same as in Specific Implementation Method One.

[0057] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the temperature equalization treatment in step three involves maintaining the temperature at 300~350℃ for 4~5 hours. Other steps and parameters are the same as in Specific Implementation Method One.

[0058] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that the welding parameters described in step three are as follows:

[0059] The welding current is 180A, the welding speed is 70mm / min, the amount of welding powder sprayed is 23g / min, the oscillation speed is 1200mm / min, the dwell time at the left end is 0.4s, the dwell time at the right end is 0.4s, the oscillation amplitude is 17mm, the ionizing gas flow rate is 4L / min, the shielding gas flow rate is 25L / min, and the powder feeding gas flow rate is 3L / min. Other steps and parameters are the same as in Specific Implementation Method 1.

[0060] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that, during the welding process described in step three, both arc initiation and arc termination are performed on the arc initiation and termination plates. Other steps and parameters are the same as in Specific Implementation Method One.

[0061] The purpose of this implementation method is to ensure that there are no defects such as undercut or porosity in the main area of ​​the weld.

[0062] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that an infrared thermometer is used for real-time monitoring during the welding process described in step three, controlling the interpass temperature to 350℃. When the temperature is insufficient, flame heating is used for supplementary heating. Other steps and parameters are the same as in Specific Implementation Method One.

[0063] In this embodiment, the interlayer temperature is strictly controlled in order to avoid cracks or poor microstructure caused by excessive temperature difference.

[0064] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method One in that the tempering heat treatment described in step four involves holding at 650°C for 4 hours. Other steps and parameters are the same as in Specific Implementation Method One.

[0065] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One in that the non-destructive testing described in step four uses PT penetrant testing at the arc initiation and termination points, and UT ultrasonic testing and MT magnetic particle testing at the remaining points. Other steps and parameters are the same as in Specific Implementation Method One.

[0066] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method One in that the standard for passing the non-destructive testing in step four is: no defects inside or on the surface of the weld, and the weld quality meets the design and usage requirements. Other steps and parameters are the same as in Specific Implementation Method One.

[0067] The beneficial effects of the present invention are verified through the following embodiments:

[0068] The following description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0069] Example:

[0070] An automated welding method for turbine rotating rings is implemented through the following steps:

[0071] I. Pre-processing:

[0072] The rotating ring and welding area were cleaned, and then the welding area was inspected using PT penetrant testing to ensure that the welding conditions were up to standard.

[0073] II. Fixed:

[0074] The rotating ring has a two-half structure. During welding, one half of the rotating ring is taken first and fixed on the turntable with a pressure plate. Then, a positioning plate is used to perform three-point positioning on the inner circle of the half rotating ring.

[0075] III. Welding and Isostatic Treatment:

[0076] After the above three points are positioned, a single-layer, single-pass plasma spraying welding method is used for welding. After welding, the ring is sent to a heating furnace for homogenization treatment. Then, the other half of the rotating ring is fixed, welded, and homogenized in the same way, thus completing the overall welding of the rotating ring.

[0077] IV. Tempering heat treatment and testing:

[0078] After the overall welding of the aforementioned rotating ring is completed, the rotating ring is subjected to tempering heat treatment, and then the weld is subjected to non-destructive testing. Once the non-destructive testing is qualified, the automated welding of the turbine rotating ring is completed.

[0079] The standard for qualified welding conditions in step one of this embodiment is that the surface of the rotating ring base material is free of cracks and porosity defects.

[0080] The three-point positioning described in step two of this embodiment involves using three positioning plates arranged along the inner circle of a half-rotation ring. The three positioning plates are located at 30°, 90°, and 150° of the inner circle, respectively.

[0081] The temperature equalization treatment described in step three of this embodiment involves maintaining the temperature at 300℃ for 5 hours.

[0082] The welding parameters described in step three of this embodiment are as follows:

[0083] The welding current is 180A, the welding speed is 70mm / min, the amount of welding powder is 23g / min, the oscillation speed is 1200mm / min, the dwell time at the left end is 0.4s, the dwell time at the right end is 0.4s, the oscillation amplitude is 17mm, the ion gas flow rate is 4L / min, the shielding gas flow rate is 25L / min, and the powder feeding gas flow rate is 3L / min.

[0084] In step three of this embodiment, the arc initiation and termination processes are both performed on the arc initiation and termination plates.

[0085] In step three of this embodiment, an infrared thermometer is used for real-time monitoring during the welding process to control the interlayer temperature at 350°C. When the temperature is insufficient, flame heating is used to supplement the heating.

[0086] In step three of this embodiment, a single-layer, single-pass plasma spraying welding method is used, that is, an automated plasma spraying welding system is used, which includes a turntable, a welding torch, and a welding power source.

[0087] The tempering heat treatment described in step four of this embodiment involves holding the temperature at 650°C for 4 hours.

[0088] The non-destructive testing described in step four of this embodiment is as follows: the arc initiation and termination areas are tested using PT penetrant testing, while the remaining areas are tested using UT ultrasonic testing and MT magnetic particle testing.

[0089] The standard for passing non-destructive testing in step four of this embodiment is: no defects inside or on the surface of the weld, and the weld quality meets the design and usage requirements.

[0090] like Figure 1 As shown, two non-adjacent positioning plates can be seen. The three-point positioning installation of the positioning plates ensures that the rotating ring and the turntable are concentric.

[0091] like Figure 2 As shown, the weld formation of the half of the rotating ring after welding is consistent, and defects are significantly reduced.

[0092] like Figure 3 As shown, after the overall welding is completed, the two halves of the rotating ring are assembled to ensure the overall concentricity and consistency of the microstructure.

Claims

1. An automated welding method for turbine rotating rings, characterized in that, It is implemented in the following steps: I. Pre-processing: The rotating ring and welding area were cleaned, and then the welding area was inspected using PT penetrant testing to ensure that the welding conditions were up to standard. II. Fixed: The rotating ring has a two-half structure. During welding, one half of the rotating ring is taken first and fixed on the turntable with a pressure plate. Then, a positioning plate is used to perform three-point positioning on the inner circle of the half rotating ring. III. Welding and Isostatic Treatment: After the above three points are positioned, a single-layer, single-pass plasma spraying welding method is used for welding. After welding, the ring is sent to a heating furnace for homogenization treatment. Then, the other half of the rotating ring is fixed, welded, and homogenized in the same way, thus completing the overall welding of the rotating ring. IV. Tempering heat treatment and testing: After the overall welding of the aforementioned rotating ring is completed, the rotating ring is subjected to tempering heat treatment, and then the weld is subjected to non-destructive testing. Once the non-destructive testing is qualified, the automated welding of the turbine rotating ring is completed.

2. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The standard for qualified welding conditions described in step one is that the surface of the rotating ring base material is free of cracks and porosity defects.

3. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The three-point positioning mentioned in step two involves using three positioning plates arranged along the inner circle of a half-rotation ring. The three positioning plates are located at 30°, 90° and 150° of the inner circle, respectively.

4. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The temperature equalization treatment described in step three involves maintaining the temperature at 300~350℃ for 4~5 hours.

5. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The welding parameters described in step three are as follows: The welding current is 180A, the welding speed is 70mm / min, the amount of welding powder is 23g / min, the oscillation speed is 1200mm / min, the dwell time at the left end is 0.4s, the dwell time at the right end is 0.4s, the oscillation amplitude is 17mm, the ion gas flow rate is 4L / min, the shielding gas flow rate is 25L / min, and the powder feeding gas flow rate is 3L / min.

6. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, In step three, the arc initiation and termination processes are both carried out on the arc initiation and termination plates.

7. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, In step three, an infrared thermometer is used for real-time monitoring during the welding process to control the interpass temperature at 350°C. When the temperature is insufficient, flame heating is used to supplement the heating.

8. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The tempering heat treatment described in step four involves holding the temperature at 650°C for 4 hours.

9. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The non-destructive testing described in step four: PT penetrant testing is used at the arc initiation and termination points, while UT ultrasonic testing and MT magnetic particle testing are used at the remaining points.

10. The automated welding method for the turbine rotating ring according to claim 1, characterized in that, The standard for passing non-destructive testing in step four is: no defects inside or on the surface of the weld, and the weld quality meets the design and usage requirements.

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