A welding process and welding tool for welding a 30CrMo high-strength steel hollow shaft

Abstract

The application provides a welding process and a welding tool for 30CrMo high-strength steel hollow shaft welding, the welding process adopts inertia friction welding, and the process parameters of the inertia friction welding are determined through the following formula: welding upset force F = π (d1 2 -d2 2 ) / 4*P; moment of inertia I = m*r 2 ; total energy E = q*s; initial rotating speed n is calculated according to the total energy E and the following formula: E = I*n 2 / 183; the welding tool comprises a main shaft side fixing seat, a main shaft side transition sleeve and a tail seat transition sleeve; the main shaft side fixing seat is provided with a connecting section and a mounting disc in the axial direction; the main shaft side transition sleeve is sleeved outside the connecting section; the mounting disc is fixedly installed on the front end face of a rotating mechanism; the outer side edge of the front end face of the mounting disc is provided with three convex arc structures at equal intervals in the circumferential direction; and the shaft body is fixedly installed in the mounting hole of the fixing mechanism of the inertia friction welding equipment through two tail seat transition sleeves which are sleeved outside. The application can guarantee the welding quality and stability of the hollow shaft and reduce the repair rate of the hollow shaft welding.

Description

Technical Field

[0001] This invention relates to the field of locomotive hollow shaft welding technology, and more particularly to a welding process and welding tooling for welding 30CrMo high-strength steel hollow shafts. Background Technology

[0002] High-strength alloy steel 30CrMo hollow shaft structures are used in various locomotive models. Currently, hollow shafts are welded using CO2 gas shielded welding. The 30CrMo material used for locomotive bogie hollow shafts is a medium-carbon alloy steel with a carbon equivalent (Ceq) of 0.6–0.8, resulting in poor weldability. To avoid cold cracking during CO2 welding, the preheating temperature should be around 200℃. Interlayer cleaning is required during welding, and slow cooling for 12 hours is necessary after welding. Existing welding methods require highly skilled welders, and the complex welding process makes welding defects more likely. Repair work is also very difficult. Due to standard restrictions, parts that have been repaired twice must be scrapped, resulting in significant economic losses due to the high cost of manufacturing the component blanks. Summary of the Invention

[0003] In response to the aforementioned technical problems, such as the complexity of the existing high-strength alloy steel 30CrMo hollow shaft welding process leading to easy welding defects and the difficulty of repair work, a welding process and welding tooling for welding 30CrMo high-strength steel hollow shafts are provided.

[0004] The technical means employed in this invention are as follows:

[0005] A welding process for welding hollow shafts made of 30CrMo high-strength steel employs inertial friction welding. The process parameters for inertial friction welding are determined using the following formula:

[0006] (1) Welding upsetting force F=π(d1) 2 -d2 2 ) / 4*P, where P represents the pressure of 30CrMo high-strength steel, d1 represents the outer diameter of the hollow shaft body, and d2 represents the inner diameter of the hollow shaft core;

[0007] (2) Moment of inertia I = m * r 2 Where m and r represent the weight and radius of the flywheel in the inertial friction welding equipment used, respectively;

[0008] (3) The total energy input to the inertial friction welding equipment is E = q*s, where q represents the energy required per unit area when 30CrMo high-strength steel is subjected to inertial friction welding, and s represents the cross-sectional area of ​​the hollow shaft body.

[0009] (4) The initial rotational speed n is calculated based on the total energy E obtained in (3) and the following formula: E=I*n2 / 183.

[0010] Furthermore, the pressure P of 30CrMo high-strength steel is 120 MPa, the energy q required per unit area for inertial friction welding of 30CrMo high-strength steel is 150 J, and the inertial friction welding process parameters used are a welding upsetting force F of 260 t and a moment of inertia I of 2629 kg·m. 2 The total energy E is 3261675J, and the initial rotational speed is 480r / min.

[0011] The present invention also provides a welding fixture for welding 30CrMo high-strength hollow shafts, the hollow shafts comprising a three-jaw disc and a shaft body; the welding fixture comprising a spindle-side fixed seat, a spindle-side transition sleeve, and a tailstock transition sleeve;

[0012] The spindle-side fixed seat is provided with a connecting section and a mounting plate along the axial direction; the spindle-side transition sleeve is sleeved on the connecting section; the connecting section with the spindle-side transition sleeve is installed in the mounting hole on the rotating mechanism of the inertial friction welding equipment; the mounting plate is fixedly installed on the front end face of the rotating mechanism, and the front end face of the spindle-side transition sleeve is in close contact with the bottom surface of the mounting plate;

[0013] The outer edge of the front face of the mounting plate has three raised arc-shaped structures at equal intervals along the circumference. The claw structure of the three-claw plate is engaged between two adjacent arc-shaped structures, thereby fixing the three-claw plate to the front end of the mounting plate.

[0014] The shaft body is fixedly installed in the mounting hole of the fixing mechanism of the inertial friction welding equipment by two tailstock transition sleeves sleeved on the outside. The tailstock fixing sleeve is used to support and fix the shaft body in the mounting hole of the fixing mechanism.

[0015] Furthermore, it also includes a pressure plate for fixing the claw structure, the two ends of which are mounted on the two arc-shaped structures for locking the claw structure.

[0016] Furthermore, the mounting plate is provided with bolt holes, and the mounting plate is fixedly installed on the front end of the rotating mechanism by installing bolts in the bolt holes.

[0017] Furthermore, the tailstock transition sleeve has a semi-annular structure.

[0018] Furthermore, the spindle-side fixing seat has a ring structure.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The welding process and welding fixtures provided by this invention can ensure the welding quality and stability of 30CrMo high-strength steel hollow shafts by inertial friction welding, and significantly reduce the rework rate of hollow shaft welding. The inertial friction welding process is energy-saving, material-saving, and environmentally friendly.

[0021] Based on the above reasons, this invention can be widely promoted in the field of locomotive hollow shaft welding. Attached Figure Description

[0022] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram showing the installation position of the welding fixture described in this invention on an inertial friction welding device.

[0024] Figure 2 This is a schematic diagram of the spindle-side fixing seat structure described in this invention.

[0025] Figure 3 This is a schematic diagram of the tailstock transition sleeve structure described in this invention.

[0026] Figure 4 This is a schematic diagram of the three-jaw disk structure described in this invention.

[0027] In the figure: 1. Three-jaw chuck; 2. Shaft body; 3. Main spindle side fixed seat; 31. Mounting plate; 32. Arc-shaped structure; 4. Main spindle side transition sleeve; 5. Tailstock transition sleeve; 6. Rotating mechanism; 7. Moving mechanism. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0033] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0034] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0035] Example 1

[0036] This invention provides a welding process for welding hollow shafts made of 30CrMo high-strength steel, which employs inertial friction welding. The process parameters for inertial friction welding are determined using the following formula:

[0037] (1) Welding upsetting force F=π(d1) 2 -d2 2 ) / 4*P, where P represents the pressure of 30CrMo high-strength steel, d1 represents the outer diameter of the hollow shaft body, and d2 represents the inner diameter of the hollow shaft core;

[0038] (2) Moment of inertia I = m * r 2 Where m and r represent the weight and radius of the flywheel in the inertial friction welding equipment used, respectively;

[0039] (3) The total energy input to the inertial friction welding equipment is E = q*s, where q represents the energy required per unit area when 30CrMo high-strength steel is subjected to inertial friction welding, and s represents the cross-sectional area of ​​the hollow shaft body.

[0040] (4) The initial rotational speed n is calculated based on the total energy E obtained in (3) and the following formula: E=I*n 2 / 183.

[0041] Preferably, the pressure P of the 30CrMo high-strength steel is 120 MPa, the energy q required per unit area for inertial friction welding of the 30CrMo high-strength steel is 150 J, and the inertial friction welding process parameters used are a welding upsetting force F of 260 t and a moment of inertia I of 2629 kg·m. 2 The total energy E is 3261675J, and the initial rotational speed is 480r / min.

[0042] Furthermore, the specific process of inertial friction welding includes: hollow shaft pre-welding preparation, hollow shaft friction welding, heat aging treatment, overall rough machining, radiographic testing, quenching and tempering treatment, overall fine machining, and magnetic particle testing.

[0043] The welding process for welding 30CrMo high-strength steel hollow shafts provided by this invention adopts inertial friction welding. During the welding process, the metal does not melt but remains in a high-temperature plastic state, which is a solid-phase thermocompression welding. The joint has a forged structure, so the weld will not have crystallization defects such as porosity, segregation, inclusions, and cracks as in fusion welding. The strength of the welded joint is much greater than that of fusion welding and brazing, reaching or even exceeding the strength of the base material. At the same time, the welding process is automatically controlled by the machine, and the parameters are easy to monitor after being set. It has good repeatability and does not depend on the operator's technical level and work attitude. Furthermore, the welding process does not produce smoke or harmful gases, does not produce spatter, does not produce arc light or sparks, and does not produce radiation, making it green, clean, and environmentally friendly.

[0044] Inertial friction welding typically has relatively low requirements for workpiece preparation, and the welding equipment is highly automated, allowing for production on assembly lines. The welding time for each workpiece is measured in seconds, generally requiring only a few seconds to complete the welding of a single workpiece. In contrast, the current hollow shaft welding using MIG welding requires preheating to 200°C before welding, followed by multi-layer, multi-pass welding, which takes a total of 90 minutes. After welding, it also requires 12 hours of heat preservation and slow cooling. Inertial friction welding does not require welding rods, flux, brazing filler metal, shielding gas, filler metal, or electrodes. It consumes only 10 kWh of electricity per shaft, making its production cost far lower than that of fusion welding. In contrast, MIG welding of hollow shafts requires the following consumables: 3 kg of welding wire per shaft, 10 L of shielding gas per shaft, 10 L of oxygen per shaft, and 8 L of propane per shaft. The heat preservation and slow cooling after welding consumes 9 kWh of electricity per shaft.

[0045] like Figure 1-4 As shown, the present invention also provides a welding fixture for welding 30CrMo high-strength hollow shafts, wherein the hollow shaft includes a three-jaw disc 1 and a shaft body 2; the welding fixture includes a spindle-side fixed seat 3, a spindle-side transition sleeve 4 and a tailstock transition sleeve 5;

[0046] The spindle-side fixed seat 3 is provided with a connecting section and a mounting plate 31 along the axial direction; the spindle-side transition sleeve 4 is sleeved on the connecting section; the connecting section with the spindle-side transition sleeve 4 is installed in the mounting hole on the rotating mechanism 6 of the inertial friction welding equipment; the mounting plate is fixedly installed on the front end face of the rotating mechanism 6, and the front end face of the spindle-side transition sleeve 4 is in close contact with the bottom surface of the mounting plate;

[0047] The outer edge of the front end face of the mounting plate 31 is provided with three raised arc-shaped structures 32 at equal intervals along the circumference. The claw structure of the three-claw plate 1 is engaged between two adjacent arc-shaped structures 32, thereby fixing the three-claw plate 1 to the front end of the mounting plate 31.

[0048] The shaft body 2 is fixedly installed in the mounting hole of the fixing mechanism 7 of the inertial friction welding equipment by two tailstock transition sleeves 5 sleeved on the outside. The tailstock fixing sleeves 5 are used to support and fix the shaft body 2 in the mounting hole of the fixing mechanism 7.

[0049] When the inertial friction welding equipment is working, the rotating mechanism 6 drives the three-jaw disk 1 to rotate at high speed through the main shaft side fixed seat 3, gradually approaching the shaft body 2 on the fixed mechanism 7. Then, the three-jaw disk 1 and the shaft body 2 are welded into a hollow shaft through inertial friction welding. The welding fixture is used to ensure the coaxiality and positioning clamping of the three-jaw disk 1 and the rotating mechanism 6 during the inertial friction welding process, as well as the stability of the shaft body 2 within the fixed mechanism 7.

[0050] Furthermore, it also includes a pressure plate for fixing the claw structure. The two ends of the pressure plate are installed on the two arc-shaped structures 32 for locking the claw structure, so that the claw structure is pressed under the pressure plate, thereby further fixing the claw structure.

[0051] Furthermore, the mounting plate 31 is provided with bolt holes, and the mounting plate 31 is fixedly installed on the front end of the rotating mechanism by installing bolts in the bolt holes.

[0052] Furthermore, the tailstock transition sleeve 5 has a semi-annular structure.

[0053] Furthermore, the spindle-side fixing seat 4 has a ring structure.

[0054] Furthermore, the present invention can employ the HW1-IFW-130 inertial friction welding equipment.

[0055] The welding process and welding fixtures provided by this invention can ensure the welding quality and stability of 30CrMo high-strength steel hollow shafts by inertial friction welding, and significantly reduce the rework rate of hollow shaft welding. The inertial friction welding process is energy-saving, material-saving, and environmentally friendly.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A welding process for welding hollow shafts made of 30CrMo high-strength steel, characterized in that, Inertial friction welding is used for welding, and the process parameters for inertial friction welding are determined by the following formula: (1) Welding upsetting force F = π (d1) 2 - d2 2 ) / 4 *P, where P represents the pressure of 30CrMo high-strength steel, d1 represents the outer diameter of the hollow shaft body, and d2 represents the inner diameter of the hollow shaft core; (2) Moment of inertia I = m * r 2 Where m and r represent the weight and radius of the flywheel in the inertial friction welding equipment used, respectively; (3) The total energy input of the inertial friction welding equipment is E=q*s, where q represents the energy required per unit area when 30CrMo high-strength steel is subjected to inertial friction welding, and s represents the cross-sectional area of ​​the hollow shaft body. (4) The initial rotational speed n is calculated based on the total energy E obtained in (3) and the following formula: E=I*n 2 / 183; The hollow shaft includes a three-jaw disc and a shaft body; the welding fixture used for inertial friction welding includes a spindle-side fixed seat, a spindle-side transition sleeve, and a tailstock transition sleeve; The spindle-side fixed seat is provided with a connecting section and a mounting plate along the axial direction; the spindle-side transition sleeve is sleeved on the connecting section; the connecting section with the spindle-side transition sleeve is installed in the mounting hole on the rotating mechanism of the inertial friction welding equipment; the mounting plate is fixedly installed on the front end face of the rotating mechanism, and the front end face of the spindle-side transition sleeve is in close contact with the bottom surface of the mounting plate; The outer edge of the front face of the mounting plate has three raised arc-shaped structures at equal intervals along the circumference. The claw structure of the three-claw plate is engaged between two adjacent arc-shaped structures, thereby fixing the three-claw plate to the front end of the mounting plate. The shaft body is fixedly installed in the mounting hole of the fixing mechanism of the inertial friction welding equipment by two tailstock transition sleeves sleeved on the outside. The tailstock fixing sleeve is used to support and fix the shaft body in the mounting hole of the fixing mechanism.

2. The welding process for welding 30CrMo high-strength steel hollow shafts according to claim 1, characterized in that, The pressure P of 30CrMo high-strength steel is 120 MPa. The energy q required per unit area for inertial friction welding of 30CrMo high-strength steel is 150 J. The inertial friction welding process parameters used are a welding upsetting force F of 260 t and a moment of inertia I of 2629 kg•m. 2 The total energy E is 3261675J, and the initial rotational speed is 480r / min.

3. The welding process for welding 30CrMo high-strength steel hollow shafts according to claim 1, characterized in that, It also includes a pressure plate for fixing the claw structure, the two ends of the pressure plate being mounted on the two arc-shaped structures for locking the claw structure.

4. The welding process for welding 30CrMo high-strength steel hollow shafts according to claim 1, characterized in that, The mounting plate is provided with bolt holes, and the mounting plate is fixedly installed on the front end of the rotating mechanism by installing bolts in the bolt holes.

5. The welding process for welding 30CrMo high-strength steel hollow shafts according to claim 1, characterized in that, The tailstock transition sleeve has a semi-circular structure.

6. The welding process for welding 30CrMo high-strength steel hollow shafts according to claim 1, characterized in that, The main shaft side mounting base has a ring structure.

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