A repair process after shaft breakage

Abstract

The application belongs to the technical field of welding repair and relates to a repair process for shaft fracture, which comprises the following steps: S1, a conical platform structure and a center hole are processed at the fracture end of the broken shaft; S2, a mandrel, a first positioning sleeve and a second positioning sleeve are prepared; S3, the first positioning sleeve and the second positioning sleeve are respectively sleeved on the two broken shafts to be repaired, and the two ends of the mandrel are respectively inserted into the center holes of the two broken shafts; S4, a pin shaft is arranged in the pin hole of the positioning sleeve, the two broken shafts are pushed to move towards each other until the end faces of the two broken shafts contact with each other, and a rotating groove is formed between the two broken shafts; S5, a repair plate is prepared; S6, a plurality of repair plates are welded in the rotating groove in a circular array direction at intervals; S7, the space between the adjacent repair plates is filled with welding; S8, the positioning sleeve is removed; and S9, the outer side wall of the repaired part is polished. The repair process can guarantee the coaxiality and strength of the broken shaft and realize the sustainable utilization of the intermediate shaft of the rolling mill.

Description

Technical Field

[0001] This invention relates to a repair process for a broken shaft, belonging to the field of welding repair technology. Background Technology

[0002] The intermediate shaft of a rolling mill is a crucial component, connecting the main motor to the work rolls. It is a key part for transmitting rolling force and plays a vital role in the rolling process. Due to the significant rolling force, the intermediate shaft must withstand substantial bending and torsional stresses. After prolonged operation, the intermediate shaft is prone to cracking and even complete breakage.

[0003] Intermediate shafts in rolling mills have high requirements for strength and coaxiality. Due to their large size and heavy weight, existing repair methods are insufficient to guarantee the quality and strength of the repaired shaft. Therefore, once an intermediate shaft breaks, it is usually the only option to scrap it. However, the cost of an intermediate shaft is quite high, and this approach not only wastes resources but also places a huge cost burden on the company.

[0004] To address this problem, the present invention provides a repair process for shaft fracture. Summary of the Invention

[0005] The purpose of this invention is to provide a new technical solution to improve or solve the technical problems existing in the prior art as described above.

[0006] The technical solution provided by this invention is as follows: a repair process for a broken shaft, comprising the following steps:

[0007] S1. Clean the broken end of the broken shaft, process a truncated cone structure at the broken end of the broken shaft, and drill a center hole along its axial direction at the center of the broken shaft.

[0008] S2. Prepare a mandrel, a first positioning sleeve, and a second positioning sleeve. The outer diameter of the mandrel is adapted to the inner diameter of the central hole, and the inner diameter of the positioning sleeve is adapted to the outer diameter of the broken shaft. Multiple pin holes are evenly distributed on the positioning sleeve along the circumferential direction.

[0009] S3. The first positioning sleeve and the second positioning sleeve are respectively fitted onto the two broken shafts to be repaired, and the two ends of the mandrel are respectively inserted into the center holes of the two broken shafts to ensure the coaxiality of the two broken shafts.

[0010] S4. Insert a pin into the pin hole of the first positioning sleeve and the second positioning sleeve, and push the two broken shafts to move towards each other until the end faces of the two broken shafts contact each other, forming a rotating groove between the two broken shafts. The cross-section of the rotating groove is V-shaped.

[0011] S5. Prepare the repair board;

[0012] S6. Weld multiple repair plates at intervals in the rotating groove along a circular array direction;

[0013] S7. Fill the space between adjacent repair plates by welding.

[0014] S8. Remove the first positioning sleeve and the second positioning sleeve;

[0015] S9. Grind the outer wall of the repaired part to remove any welding marks or uneven parts.

[0016] Compared with the prior art, the technical solution provided by this invention has the following beneficial effects: the repair process after shaft fracture of this invention can ensure the coaxiality and strength of the broken shaft, thereby enabling the sustainable use of the intermediate shaft of the rolling mill, which not only avoids the waste of resources, but also saves costs for enterprises.

[0017] Based on the above technical solution, the present invention can be further improved as follows.

[0018] Furthermore, in step S5, the repair plate is an inverted trapezoidal plate, and the bottom of the repair plate maintains a certain distance from the bottom of the rotating groove so as not to contact it.

[0019] The beneficial effect of adopting the above-mentioned further solution is that, since the bottom size of the rotating groove is small, a gap is reserved between the bottom of the repair plate and the bottom of the rotating groove to ensure that the bottom of the repair plate is welded to the rotating groove in place, and to ensure that the repair plate is firmly connected to the bottom of the rotating groove during welding.

[0020] Furthermore, the two sides of the inverted trapezoidal plate are inclined surfaces, and the inclined surfaces form a welding bevel with the side wall of the rotating groove. The two sides of the inverted trapezoidal plate are welded to the side walls of the rotating groove through the welding bevel.

[0021] The beneficial effect of adopting the above-mentioned further solution is that it can increase the depth and width of the weld between the inverted trapezoidal plate and the rotating groove, thereby improving the strength and durability of the welded joint.

[0022] Furthermore, in step S5, the repair plate is a V-shaped plate, and the shape of the V-shaped plate is adapted to the shape of the cross-section of the rotating groove.

[0023] Furthermore, in step S4, at least one layer of underlay weld is first welded inside the rotating groove, and the underlay weld forms a flange above the rotating groove.

[0024] Furthermore, in steps S6 and / or S7, the weld is hammered each time welding is completed.

[0025] The beneficial effects of adopting the above-mentioned further solutions are that hammering can eliminate or change the stress generated during the welding process, improve the fatigue resistance of the weld, prevent the generation of cracks, and improve the reliability of the workpiece.

[0026] Furthermore, in step S1, after machining a frustum-shaped structure at the broken end of the broken shaft, a colorimetric flaw detection is performed. According to the flaw detection structure, if there are no cracks on the surface, the broken end is processed; if there are cracks on the surface, further planing is required.

[0027] The beneficial effect of adopting the above-mentioned further scheme is that, through dye penetrant testing, defects near the surface of the broken shaft, such as cracks, pores, and looseness, can be detected. This testing method can improve the repair quality of the broken shaft.

[0028] Furthermore, in step S5, the dimensions of the cross-section of the rotating groove are measured, and a repair plate is prepared based on the measured dimensions.

[0029] Furthermore, in step S1, an air gouging tool is used to clean the broken end of the broken shaft.

[0030] Furthermore, in step S2, the mandrel and the center hole are fitted with an interference fit or a transition fit. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the broken shaft structure of the present invention;

[0033] Figure 2 This is a schematic diagram of steps S3 and S4 of the present invention;

[0034] Figure 3 This is a schematic diagram of step S6 of the present invention;

[0035] Figure 4 For the present invention Figure 3 A partial sectional view;

[0036] Figure 5 This is a three-dimensional structural diagram of the inverted trapezoidal plate of the present invention;

[0037] Figure 6 For the present invention Figure 5 The main view;

[0038] Figure 7 For the present invention Figure 5 The left view;

[0039] Figure 8 For the present invention Figure 5 Top view;

[0040] Figure 9 For the present invention Figure 5 Bottom view;

[0041] In the diagram, 1. Broken shaft; 2. Frustum; 3. Center hole; 4. Mandrel; 5. First positioning sleeve; 6. Second positioning sleeve; 7. Pin; 8. Rotary groove; 9. Inverted trapezoidal plate; 901. Inclined surface; 10. V-shaped plate; 11. Gap. Detailed Implementation

[0042] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0043] Reference 1- Figure 4 As shown, a repair process for a broken shaft includes the following steps:

[0044] S1. Clean the broken end of the broken shaft 1, process a truncated cone 2 structure at the broken end of the broken shaft 1, and drill a central hole 3 along its axial direction at the center of the broken shaft 1.

[0045] S2. Prepare a mandrel 4, a first positioning sleeve 5, and a second positioning sleeve 6. The outer diameter of the mandrel 4 is adapted to the inner diameter of the center hole 3, and the inner diameter of the positioning sleeve is adapted to the outer diameter of the broken shaft 1. The positioning sleeve has multiple pin holes evenly distributed along the circumferential direction. The mandrel 4 and the center hole 3 can be an interference fit or a transition fit.

[0046] S3. The first positioning sleeve 5 and the second positioning sleeve 6 are respectively fitted onto the two broken shafts 1 to be repaired. The two ends of the mandrel 4 are respectively inserted into the center holes 3 of the two broken shafts 1 to ensure the coaxiality of the two broken shafts 1.

[0047] S4. Insert a pin 7 into the pin hole of the first positioning sleeve 5 and the second positioning sleeve 6. One end of the pin 7 is connected to the first positioning sleeve 5, and the other end is inserted into the pin hole of the second positioning sleeve 6. Push the two broken shafts 1 to move towards each other until the end faces of the two broken shafts 1 contact each other, and a 360° rotating groove 8 is formed between the two broken shafts 1. The cross-section of the rotating groove 8 is V-shaped.

[0048] S5. Prepare the repair board;

[0049] S6. Weld multiple repair plates at intervals in the rotating groove 8 around the axis of the broken shaft 1 in a circular array direction;

[0050] S7. Fill the space between adjacent repair plates by welding.

[0051] S8. Remove the first positioning sleeve 5 and the second positioning sleeve 6;

[0052] S9. Grind the outer wall of the repaired part to remove any welding marks or uneven parts.

[0053] In addition, in this embodiment,

[0054] like Figures 5-9 As shown, in step S5, the repair plate is an inverted trapezoidal plate 9, and the bottom of the repair plate maintains a certain distance from the bottom of the rotating groove 8, without contacting it. Because the bottom of the rotating groove 8 is relatively small, a gap 11 is reserved between the bottom of the repair plate and the bottom of the rotating groove 8 (e.g., ...). Figure 4 As shown in the diagram, this ensures that the bottom of the repair plate is welded to the rotating groove 8, guaranteeing a firm connection between the repair plate and the bottom of the rotating groove 8 during welding. The two sides of the inverted trapezoidal plate 9 are inclined surfaces 901, which form a welding bevel with the sidewall of the rotating groove 8. This welding bevel connects the two sides of the inverted trapezoidal plate 9 to the sidewalls of the rotating groove 8. This increases the depth and width of the weld between the inverted trapezoidal plate 9 and the rotating groove 8, improving the strength and durability of the weld joint.

[0055] Of course, the repair plate can also be a V-shaped plate 10 that matches the shape of the rotating groove 8, and a more advanced welding process can be used to ensure the welding effect. Therefore, the embodiments of the present invention do not limit the shape of the repair plate, as long as the repair plate can achieve the connection between the two broken shafts 1, it should be within the protection scope of the present invention.

[0056] In step S4, at least one layer of underlay weld is first welded inside the rotating groove 8, and the underlay weld forms a flange above the rotating groove 8.

[0057] In steps S6 and / or S7, the weld is hammered after each welding operation. Hammering can eliminate or alter the stress generated during welding, improve the fatigue resistance of the weld, prevent crack formation, and enhance the reliability of the workpiece.

[0058] In step S1, after machining the truncated cone 2 structure at the fracture end of the broken shaft 1, dye penetrant testing is performed. Based on the test results, if there are no cracks on the surface, the fracture end treatment is complete; if there are cracks on the surface, further planing is required. Dye penetrant testing can detect defects near the surface of the broken shaft 1, such as cracks, porosity, and looseness. This testing method can improve the repair quality of the broken shaft 1.

[0059] In step S5, the dimensions of the cross-section of the rotating groove 8 are measured, and a repair plate is prepared according to the measured dimensions.

[0060] In step S1, an air gouging tool is used to clean the broken end of the broken shaft 1.

[0061] The repair process for shaft breakage of the present invention can ensure the coaxiality and strength of the broken shaft 1, thereby enabling the sustainable use of the intermediate shaft of the rolling mill, which not only avoids the waste of resources, but also saves costs for enterprises.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The present invention is not only applicable to the repair of large broken shafts 1, such as intermediate shafts of rolling mills, but also applicable to the repair of small broken shafts 1. 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.

Claims

1. A repair process for a broken shaft, characterized in that, The steps include the following: S1. Clean the broken end of the broken shaft (1), process a truncated cone (2) structure at the broken end of the broken shaft (1), and drill a center hole (3) along its axial direction at the center of the broken shaft (1). S2. Prepare a mandrel (4), a first positioning sleeve (5) and a second positioning sleeve (6). The outer diameter of the mandrel (4) is adapted to the inner diameter of the center hole (3). The inner diameters of the first positioning sleeve (5) and the second positioning sleeve (6) are adapted to the outer diameter of the broken shaft (1). Multiple pin holes are evenly distributed along the circumferential direction on the first positioning sleeve (5) and the second positioning sleeve (6). S3. The first positioning sleeve (5) and the second positioning sleeve (6) are respectively fitted onto the two broken shafts (1) to be repaired. The two ends of the mandrel (4) are respectively inserted into the center holes (3) of the two broken shafts (1) to ensure the coaxiality of the two broken shafts (1). S4. A pin (7) is inserted into the pin hole of the first positioning sleeve (5) and the second positioning sleeve (6) to push the two broken shafts (1) to move towards each other until the end faces of the two broken shafts (1) come into contact with each other, and a rotating groove (8) is formed between the two broken shafts (1). The cross-section of the rotating groove (8) is V-shaped. S5. Prepare the repair board; S6. Weld multiple repair plates at intervals along a circular array direction into the rotating groove (8); S7. Fill the space between adjacent repair plates by welding. S8. Remove the first positioning sleeve (5) and the second positioning sleeve (6); S9. Grind the outer wall of the repaired part to remove any welding marks or uneven parts; In step S5, the repair plate is an inverted trapezoidal plate (9), and the bottom of the repair plate is kept at a certain distance from the bottom of the rotating groove (8) and does not contact it; In step S6 and / or step S7, the weld is hammered each time welding is completed.

2. The repair process for shaft fracture according to claim 1, characterized in that, The two sides of the inverted trapezoidal plate (9) are inclined surfaces (901), and the inclined surfaces (901) form a welding bevel with the side wall of the rotating groove (8). The two sides of the inverted trapezoidal plate (9) are welded to the side wall of the rotating groove (8) through the welding bevel.

3. The repair process for shaft fracture according to claim 1, characterized in that, In step S5, the repair plate is a V-shaped plate (10), and the shape of the V-shaped plate (10) is adapted to the shape of the cross-section of the rotating groove (8).

4. The repair process for shaft fracture according to any one of claims 1 to 3, characterized in that, In step S4, at least one layer of underlay weld is first welded in the rotating groove (8), and the underlay weld forms a flange above the rotating groove (8).

5. The repair process for shaft fracture according to claim 1, characterized in that, In step S1, after machining a truncated cone (2) structure at the fracture end of the broken shaft (1), a colorimetric flaw detection is performed. According to the flaw detection structure, if there are no cracks on the surface, the fracture end is processed. If there are cracks on the surface, further planing is required.

6. The repair process for shaft fracture according to any one of claims 1, characterized in that, In step S5, the dimensions of the cross-section of the rotating groove (8) are measured, and a repair plate is prepared according to the measured dimensions.

7. The repair process for shaft fracture according to claim 1 or 6, characterized in that, In step S1, an air gouging tool is used to clean the broken end of the broken shaft (1).

8. The repair process for shaft fracture according to claim 1, characterized in that, In step S2, the mandrel (4) and the center hole (3) are fitted with an interference fit or a transition fit.

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