Bearing bush repair welding method

Abstract

The invention relates to the field of bearing bushes, and discloses a bearing bush repair welding method which comprises the following steps: carrying out ultrasonic detection on a bearing bush to determine a flaking and falling position; the method comprises the following steps: removing flaked and fallen black metal until a tile body is formed, exposing metallic luster, enabling the intact part of the black metal and the tile body to form an obtuse included angle, carrying out tinning and black metal surfacing by using a self-made welding wire through argon tungsten-arc welding, and in the welding process, using a direct-current manual argon tungsten-arc welding machine with a high-frequency arc striking function and adopting a direct-current positive connection mode; the fault position is accurately positioned through ultrasonic detection, the optimized welding groove design and the self-made welding wire are combined, and the welding quality and efficiency of bearing bush repair are remarkably improved through the high efficiency and stability of argon tungsten-arc welding. And meanwhile, by strictly controlling welding parameters and adopting double detection means, welding defects and stress are effectively reduced, the repair cost is reduced, dependence on imported equipment and welding materials is avoided, and remarkable economic benefits and wide industrial application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the field of bearing bushes, and in particular to a method for welding and repairing bearing bushes. Background Art

[0002] A bearing bush is a key component in a sliding bearing that directly contacts the shaft, and its performance directly affects the operation stability and reliability of the equipment. A bearing bush is usually composed of a bush body and a lining alloy material. The bush body material is mainly carbon steel, and copper is also used in some cases; the lining alloy material is mainly Babbitt alloy (also known as white metal). Babbitt alloy is divided into tin-based and lead-based types. Among them, tin-based Babbitt alloy is widely used in power plant equipment due to its excellent comprehensive performance. Taking tin-based Babbitt alloy as an example, its typical composition is: Sn 83%, Sb 11%, Cu 6%, and the corresponding grade is ZChSnSb11-6. To ensure good bonding between the bush body and the Babbitt alloy, a tin layer is usually provided between them.

[0003] However, during actual use, due to improper casting processes, unstable working conditions (such as too high temperature, exceeding 100°C, or excessive vibration), etc., faults such as local melting, collapse, or separation of the bush body may occur in the bearing bush. For such faults, welding repair is an economical and practical maintenance method. The traditional bearing bush welding repair process includes two processes: tinning and Babbitt surfacing, and the oxyacetylene flame welding repair method was often used in the past. However, this method has obvious deficiencies: the heat affected zone is large, and the temperature is difficult to accurately control. When the temperature is insufficient, poor fusion is likely to occur, and when the temperature is too high, shelling is likely to occur, seriously affecting the welding repair quality.

[0004] In recent years, the tungsten inert gas arc welding repair process has gradually received attention. Through the inert gas protection of argon gas, the arc heat is concentrated, the heat affected zone is significantly reduced, and the temperature control is more accurate. It can effectively avoid many problems of traditional oxyacetylene flame welding repair, thereby obtaining high-quality deposited metal. It is a welding process with simple operation and stable quality. However, currently, more advanced and efficient argon arc welding repair technologies and special welding materials for bearing bushes are monopolized by foreign companies for a long time. It is necessary to purchase extremely expensive imported welding equipment, increasing the cost and difficulty of power plant equipment maintenance. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that more advanced and efficient argon arc welding repair technologies and special welding materials for bearing bushes are monopolized by foreign companies for a long time. It is necessary to purchase extremely expensive imported welding equipment, increasing the cost and difficulty of power plant equipment maintenance.

[0006] The above technical problem is solved by the following technical solution: The present invention provides a method for welding and repairing a bearing bush, which includes the following steps:

[0007] Perform ultrasonic testing on the bearing bush to determine the position of shelling and peeling. Conduct a comprehensive scan of the bearing bush through ultrasonic testing technology to accurately locate the position of shelling and peeling, providing an accurate reference for subsequent repair work;

[0008] Remove the white metal that has shelled and peeled off to the bearing shell, and expose the metallic luster, forming an obtuse angle between the intact part of the white metal and the bearing shell, ensuring the cleanliness and integrity of the welding surface, providing a good foundation for subsequent welding, and at the same time optimizing the angle of the welding groove, which helps to reduce the heat input during welding and reduce the thermal influence on the base material;

[0009] Use self-made welding wire to carry out tinning and white metal surfacing through tungsten inert gas welding. Using self-made welding wire for tinning and white metal surfacing, combined with the high efficiency and stability of tungsten inert gas welding, ensures the welding quality, eliminates the need to purchase welding wire, and reduces costs;

[0010] During the welding process, use a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function, and adopt the DC straight polarity connection method. Use a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function for welding, eliminating the need to purchase a special welding machine, and adopting the DC straight polarity connection method can effectively improve the welding efficiency and reduce welding defects.

[0011] In a preferred embodiment of the bearing bush welding repair method of the present invention: the intact part after white metal removal forms a 145° angle with the end face of the bearing shell. The design with an angle of 145° plays a key role in the welding process. By reducing the fusion ratio, it effectively reduces the melting amount of the base material, thereby reducing the influence of welding heat on the base material and avoiding welding defects (such as poor fusion, shelling, etc.) caused by excessive melting of the base material.

[0012] In a preferred embodiment of the bearing bush welding repair method of the present invention: the self-made welding wire is processed by melting block-shaped tin and tin-based Babbitt alloy materials, and the wire specification is a cross-section of 3 mm to 6 mm;

[0013] And the preparation process of the self-made welding wire includes: melting the Babbitt alloy in a container using an oxyacetylene flame, and taking it out after cooling to obtain a welding wire with a cross-section of 3 mm to 6 mm;

[0014] The Babbitt alloy can be melted in the module notch using an oxyacetylene flame and taken out after cooling;

[0015] It can also be melted in the groove of the angle steel using an oxyacetylene flame and taken out after cooling.

[0016] In a preferred embodiment of the bearing shell welding repair method of the present invention: both the tinning process and the white metal surfacing process adopt the methods of segmented, backstep, cross, single-pass welding, and non-swinging, and control the bead thickness and length to reduce heat input. By precisely controlling the heat distribution and input during the welding process, the welding stress and deformation are effectively reduced, and welding defects (such as cracks, lack of fusion, etc.) are reduced, thereby ensuring the quality and structural stability of the welded joint, while improving the welding efficiency and meeting the high-precision requirements of bearing shell repair.

[0017] In a preferred embodiment of the bearing shell welding repair method of the present invention: in the tinning process, the welding current is 30 - 35 A, the argon gas flow rate is 6 - 8 L / min, the interpass temperature is 60 - 70 °C, the bead thickness is not more than 2 mm, and the bead length is not more than 50 mm, which can effectively reduce the welding heat input, avoid overheating of the base metal and expansion of the heat-affected zone, thereby reducing the welding stress and deformation, and reducing welding defects (such as cracks, lack of fusion, etc.), ensuring the quality and structural stability of the welded joint, and meeting the high-precision requirements of bearing shell repair.

[0018] In a preferred embodiment of the bearing shell welding repair method of the present invention: in the white metal surfacing process, the welding current is 25 - 30 A, the argon gas flow rate is 6 - 8 L / min, the interpass temperature is 60 - 70 °C, the thickness of each bead is not more than 4 mm, and the bead length is less than 50 mm, which can effectively reduce the welding heat input, avoid overheating of the base metal and expansion of the heat-affected zone, reduce the welding stress and deformation, and reduce welding defects (such as cracks, lack of fusion, etc.), thereby ensuring the quality and structural stability of the welded joint and meeting the high-precision requirements of bearing shell repair; at the same time, since the white metal surfacing is carried out with these parameters and the interpass temperature is reasonably controlled, different types of butt welding can be adopted according to needs, without the traditional "zigzag" butt welding method.

[0019] In a preferred embodiment of the bearing shell welding repair method of the present invention: the welding power source adopts a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function. In the arc heat balance, the workpiece accounts for 70% and the tungsten electrode accounts for 30%, ensuring the stable combustion of the welding arc. Even in the case of a small current (<10 A), the arc can remain stable. The DC straight polarity connection method is adopted to make the workpiece obtain more heat, improve the welding efficiency, thereby effectively reducing the arc fluctuation during the welding process, improving the welding quality, while reducing the loss of the tungsten electrode and prolonging the service life of the tungsten electrode.

[0020] In a preferred embodiment of the bearing shell welding repair method of the present invention: in the babbit surfacing process, after each layer of weld bead is welded, the weld bead is gently tapped with a round-headed hammer. After each layer of each weld bead is cooled to below 60°C, the babbit surface is wiped with a white cotton cloth dipped in anhydrous ethanol. After each layer of weld bead is welded, the weld bead is gently tapped with a round-headed hammer to release the welding stress and reduce the internal stress generated during welding. After each layer of each weld bead is cooled to below 60°C, the babbit surface is wiped with a white cotton cloth dipped in anhydrous ethanol to remove the oxides and impurities generated during welding, thereby effectively reducing the welding stress, improving the performance and reliability of the welded joint, and ensuring the bonding quality of the subsequent welding layers at the same time.

[0021] In a preferred embodiment of the bearing shell welding repair method of the present invention: after welding is completed, ultrasonic and penetrant inspections are carried out on the weld bead. Ultrasonic testing (UT) is used to detect internal welding defects such as cracks and lack of fusion; penetrant testing (PT) is used to detect surface welding defects such as cracks and pores, thereby ensuring that the welding quality meets the standards, promptly discovering and repairing potential welding defects, and improving the reliability and safety of the bearing shell.

[0022] The beneficial effects of the present invention are as follows: By accurately positioning the fault location through ultrasonic testing, combined with the optimized welding groove design and self-made welding wire, and utilizing the high efficiency and stability of tungsten inert gas welding, the welding quality and efficiency of bearing shell repair are significantly improved. At the same time, by strictly controlling the welding parameters and adopting double inspection means, welding defects and stresses are effectively reduced, the repair cost is lowered, and the dependence on imported equipment and welding materials is avoided, with significant economic benefits and broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention and do not limit the present invention.

[0024] Figure 1 Shows a schematic diagram of the angle between the bearing shell and the babbit of the present invention.

[0025] Figure 2 Shows a schematic diagram of the module and the groove of the present invention.

[0026] Figure 3 Shows a schematic diagram of the angle steel of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with the specific embodiments and the drawings.

[0028] The terms used in the present invention are those general terms that are currently widely used in the art in consideration of the functions of the present invention. However, these terms may vary according to the intention of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present invention.

[0029] Referring to Figure 1 , this embodiment provides a method for welding and repairing a bearing shell, which includes the following steps:

[0030] Perform ultrasonic detection on the bearing shell to determine the position of shelling and peeling. Through ultrasonic detection technology, comprehensively scan the bearing shell to accurately locate the position of shelling and peeling, providing an accurate reference for subsequent repair work;

[0031] Remove the babbitt 2 that has shelled and peeled from the bearing shell body 1 and expose the metallic luster, forming an obtuse angle between the intact part of the babbitt 2 and the bearing shell body 1, ensuring the cleanliness and integrity of the welding surface, providing a good foundation for subsequent welding, and at the same time optimizing the angle of the welding groove, which helps to reduce the heat input during welding and reduce the thermal influence on the base material;

[0032] Use self-made welding wire to carry out tinning and babbitt surfacing by tungsten inert gas welding. Using self-made welding wire for tinning and babbitt surfacing, combined with the high efficiency and stability of tungsten inert gas welding, ensures the welding quality, eliminates the need to purchase welding wire, and reduces costs;

[0033] During the welding process, use a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function and adopt the DC straight polarity connection method. Using a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function for welding eliminates the need to purchase a special welding machine and adopts the DC straight polarity connection method, which can effectively improve the welding efficiency and reduce welding defects.

[0034] After welding is completed, perform ultrasonic and penetrant inspections on the weld bead. Use ultrasonic testing (UT) to detect internal welding defects such as cracks and lack of fusion; use penetrant testing (PT) to detect surface welding defects such as cracks and pores, thereby ensuring that the welding quality meets the standards, promptly discovering and repairing potential welding defects, and improving the reliability and safety of the bearing shell.

[0035] First, use ultrasonic testing technology to comprehensively scan the bearing bush, accurately locate the position of shelling and peeling, and provide an accurate reference for subsequent repair. Subsequently, remove the babbitt that has shelled and peeled off to the bearing shell, and expose the metallic luster. At the same time, optimize the welding groove angle to ensure that the welding surface is clean and complete, reduce the welding heat input, and reduce the heat influence on the base metal. During the welding process, use self-made welding wire combined with tungsten inert gas welding for tinning and babbitt surfacing. Utilize a DC manual tungsten inert gas arc welding machine with a high-frequency arc starting function and the DC straight polarity connection method, without the need to purchase special welding machines and welding wires, effectively reducing costs, while improving welding efficiency and reducing welding defects. After welding, conduct double inspections on the weld bead through ultrasonic testing (UT) and penetrant testing (PT) to promptly detect and repair internal and surface defects, ensure that the welding quality meets the standards, and significantly improve the reliability and safety of the bearing bush.

[0036] In one of the provided embodiments, as Figure 1 , the intact part after removing the babbitt 2 forms a 145° angle with the end face 11 of the bearing shell 1. The design with an angle of 145° plays a key role in the welding process. By reducing the fusion ratio, it effectively reduces the melting amount of the base metal, thereby reducing the influence of welding heat on the base metal and avoiding welding defects (such as poor fusion, shelling, etc.) caused by excessive melting of the base metal.

[0037] In one of the provided embodiments, as Figure 2 , Figure 3 , the self-made welding wire is processed by melting block-shaped tin and tin-based Babbitt alloy materials, and the wire specification is a cross-section of 3 mm to 6 mm;

[0038] And the preparation process of the self-made welding wire includes: melting the Babbitt alloy in a container using an oxyacetylene flame, and taking it out after cooling to obtain a welding wire with a cross-section of 3 mm to 6 mm;

[0039] The Babbitt alloy can be melted in the notch 4 of the module 3 using an oxyacetylene flame and taken out after cooling;

[0040] It can also be melted in the slot of the angle steel 5 using an oxyacetylene flame and taken out after cooling.

[0041] In one of the provided embodiments, as Figure 1 , both the tinning process and the babbitt surfacing process adopt the methods of segmented, backward welding, cross, single-pass welding, non-swinging, and control the thickness and length of the weld bead to reduce heat input. By precisely controlling the heat distribution and input amount during the welding process, effectively reduce welding stress and deformation, and reduce welding defects (such as cracks, lack of fusion, etc.), thereby ensuring the quality and structural stability of the welded joint, while improving welding efficiency and meeting the high-precision requirements of bearing bush repair.

[0042] In the tinning process, the welding current is 30 - 35 A, the argon gas flow rate is 6 - 8 L / min, the interlayer temperature is 60 - 70 °C, the weld bead thickness is not more than 2 mm, and the weld bead length is not more than 50 mm. This can effectively reduce the welding heat input, avoid overheating of the base metal and expansion of the heat-affected zone, thereby reducing welding stress and deformation, reducing welding defects (such as cracks, lack of fusion, etc.), ensuring the quality and structural stability of the welded joint, and meeting the high-precision requirements for bearing bush repair.

[0043] In the white metal surfacing process, the welding current is 25 - 30 A, the argon gas flow rate is 6 - 8 L / min, the interlayer temperature is 60 - 70 °C, the thickness of each weld bead is not more than 4 mm, and the weld bead length is less than 50 mm. This can effectively reduce the welding heat input, avoid overheating of the base metal and expansion of the heat-affected zone, reduce welding stress and deformation, reduce welding defects (such as cracks, lack of fusion, etc.), thereby ensuring the quality and structural stability of the welded joint and meeting the high-precision requirements for bearing bush repair; at the same time, when using these parameters for white metal surfacing and reasonably controlling the interlayer temperature, different types of butt welding can be adopted according to needs, without the traditional "zigzag" butt welding method.

[0044] In the white metal surfacing process, after each layer of weld bead is welded, gently tap the weld bead with a round-headed hammer. After each layer of weld bead is welded and cooled to below 60 °C, wipe the white metal surface with a white cotton cloth dipped in anhydrous ethanol. After each layer of weld bead is welded, gently tap the weld bead with a round-headed hammer to release the welding stress and reduce the internal stress generated during welding. After each layer of weld bead is welded and cooled to below 60 °C, wipe the white metal surface with a white cotton cloth dipped in anhydrous ethanol to remove the oxides and impurities generated during welding, thereby being able to effectively reduce the welding stress, improve the performance and reliability of the welded joint, and at the same time ensure the bonding quality of the subsequent welding layers.

[0045] The present invention optimizes the parameters and operation processes of the tinning and white metal surfacing processes, adopts welding methods such as segmented, backstep, cross, single-pass, and non-waving, and strictly controls the welding current, argon gas flow rate, interlayer temperature, weld bead thickness, and length, effectively reducing the welding heat input. This process principle reduces the generation of welding defects (such as cracks, lack of fusion, etc.) while reducing welding stress and deformation, ensuring the high quality and structural stability of the welded joint. In addition, through post-welding treatment measures such as gently tapping the weld bead to release stress and wiping the surface with anhydrous ethanol to remove impurities, the performance and reliability of the welded joint are further improved. In summary, the present invention not only effectively improves the welding quality and efficiency of bearing bush repair, but also significantly reduces the repair cost, having significant economic benefits and broad industrial application prospects.

[0046] In an example provided, as Figure 1, the welding power source uses a DC manual tungsten inert gas arc welding machine with high-frequency arc ignition function. In the arc heat balance, the workpiece accounts for 70% and the tungsten electrode accounts for 30%, ensuring the stable combustion of the welding arc. Even in the case of small current (<10A), the arc can be kept stable. The DC straight polarity connection method is adopted to make the workpiece obtain more heat, improve the welding efficiency, effectively reduce the arc fluctuation during welding, improve the welding quality, and at the same time reduce the loss of the tungsten electrode and extend the service life of the tungsten electrode.

[0047] Finally, it should be noted that the methods and devices described in detail above are only examples, and those skilled in the art can modify these examples in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A bearing welding method, characterized in that: The following steps are involved: Perform ultrasonic testing on the bearing shell to determine the location of peeling and shedding; Remove the peeled black gold (2) to the tile body (1) to expose the metallic luster, so that the intact part of the black gold (2) forms an obtuse angle with the tile body (1); Use homemade welding wire to perform tinning and black gold cladding by tungsten inert gas welding; During the welding process, a DC manual tungsten inert gas arc welding machine with high-frequency arc ignition function is used, and a DC positive connection method is adopted.

2. The bearing bushing welding repair method according to claim 1, characterized in that: The intact portion after the black gold (2) is removed forms an angle of 145° with the end surface (11) of the tile body (1).

3. The bearing bushing welding repair method according to claim 2, characterized in that: Homemade welding wire is made by melting block tin and tin-based babbitt alloy materials, and the welding wire specifications are 3 mm to 6 mm in cross section; The preparation process of the homemade welding wire includes: melting the babbitt alloy in a container by using an oxyacetylene flame, taking it out after cooling, and obtaining the welding wire with a cross-section of 3 mm to 6 mm.

4. The bearing bushing welding repair method according to claim 2 or 3, characterized in that: Both the tinning process and the black gold cladding process adopt the methods of segmentation, back-welding, cross-welding, single-pass welding, and non-swinging, and control the thickness and length of the weld to reduce heat input.

5. The bearing bushing welding repair method according to claim 4, characterized in that: In the tinning process, the welding current is 30-35A, the argon gas flow rate is 6-8L / min, the interlayer temperature is 60-70℃, the weld thickness is not more than 2mm, and the weld length is not more than 50mm.

6. The bearing bushing welding repair method according to claim 5, characterized in that: In the black gold cladding process, the welding current is 25-30A, the argon gas flow rate is 6-8L / min, the interlayer temperature is 60-70℃, the thickness of each weld is not more than 4mm, and the weld length is less than 50mm.

7. The bearing bushing welding repair method according to claim 5 or 6, characterized in that: The welding power source adopts a DC manual tungsten electrode argon arc welding machine with high-frequency arc starting function. The workpiece accounts for 70% and the tungsten electrode accounts for 30% in the arc heat balance.

8. The bearing bushing welding repair method according to claim 7, characterized in that: In the black gold cladding process, tap the weld lightly with a round hammer after each weld. When each weld is cooled to below 60°C, wipe the black gold surface with white cotton cloth dipped in anhydrous ethanol.

9. The bearing bushing welding repair method according to claim 8, characterized in that: After welding is completed, the weld is subjected to ultrasonic and dye testing.

Images