Method for calculating centrifugal casting speed of tin-based bearing alloy

Abstract

This invention relates to a method for calculating the centrifugal casting speed of tin-based bearing alloys, belonging to the technical field of determining process parameters for centrifugal casting of bearing alloys. The invention addresses the technical problem that existing speed calculation formulas for centrifugal casting of sliding bearing bushes cannot establish a quantitative relationship between the bonding force between the alloy layer and the steel backing of the bush and the speed, leading to low bonding quality between the alloy layer and the bush body. Therefore, this invention proposes a method for calculating the centrifugal casting speed of tin-based bearing alloys, used for centrifugally casting a tin-based Babbitt alloy layer on the inner surface of the bush body. The centrifugal casting speed is calculated using the following power function formula: n = 11058 × R ‑0.582 In the formula, n is the rotational speed during centrifugal casting, measured in revolutions per minute; R is the inner diameter of the bearing, measured in millimeters. Using the rotational speed calculated by the formula of this invention for centrifugal casting, the bonding force of the resulting bearing bush can be stably controlled within the high-performance range of 40–60 MPa.

Description

Technical Field

[0001] This invention relates to a method for calculating the centrifugal casting speed of tin-based bearing alloys, belonging to the technical field of methods for determining process parameters of centrifugal casting of bearing alloys. Background Technology

[0002] Tin-based Babbitt metal is widely used as a lining material for steel-backed bearing bushes due to its excellent anti-friction and compliance properties. In bearing bush manufacturing, centrifugal casting is the mainstream process for achieving metallurgical bonding between the alloy layer and the steel backing. Rotation speed, as a core process parameter in centrifugal casting, directly determines the magnitude of the centrifugal pressure exerted on the molten alloy during casting, thus affecting the density of the alloy layer, the bonding strength with the steel backing, and the final product's service life.

[0003] For a long time, the industry has primarily relied on empirical or semi-empirical formulas, such as the Konstantinov formula, the Bruzov calculation formula, and the Caiman formula, proposed by Soviet scholars, to determine the centrifugal casting speed. However, in the production of high-performance bearings,

[0004] The Konstantinov formula, based on fluid mechanics, aims to ensure that the molten alloy forms a uniform cylindrical shape during rotation, preventing dripping or falling; it only addresses the "forming" problem. However, this formula does not consider "metallurgical bonding strength" as a design objective. Therefore, the centrifugal pressure generated by its calculated rotational speed is far from sufficient to effectively compensate for shrinkage, expel interfacial gases, and promote interatomic diffusion during solidification, failing to meet the bonding strength requirements of high-performance bearings. The Bruzov formula introduces empirical correction coefficients, but these coefficients have a wide range. For a bearing with a given inner diameter, its calculation results in a large range of rotational speeds, failing to provide a definite optimal speed value. The Caiman formula, based on the simple empirical criterion that "centrifugal force is several times the gravity," has an oversimplified theoretical model, and the calculated rotational speed values ​​cannot meet the production requirements of high-performance tin-based bearing alloys.

[0005] In summary, when the sliding bearing bush is produced using centrifugal casting, the existing speed calculation formula cannot establish a quantitative relationship between the bonding force between the bearing bush alloy layer and the steel backing and the speed, resulting in a technical problem of low bonding quality between the bearing bush alloy layer and the bush body. Summary of the Invention

[0006] This invention addresses the technical problem of low bonding quality between the alloy layer and the bearing body when using centrifugal casting for sliding bearing bushes. Existing speed calculation formulas fail to establish a quantitative relationship between the bonding force between the alloy layer and the steel backing of the bush and the speed, leading to poor bonding quality. Therefore, this invention proposes a method for calculating the centrifugal casting speed of tin-based bearing alloys. This method is used for centrifugally casting tin-based Babbitt alloy layers onto the inner surface of the bearing bush. The centrifugal casting speed is calculated using the following power function formula:

[0007] n=11058×R -0.582

[0008] In the formula, n is the rotational speed during centrifugal casting, in revolutions per minute; R is the inner diameter of the bearing, in millimeters.

[0009] As another improvement of the present invention, centrifugal casting tests were conducted at different speeds for tiles with different inner diameters to obtain the speed data that enabled the bonding force between the tin-based Babbitt alloy layer and the tile to reach 40-60 MPa for each inner diameter; regression fitting was performed on the inner diameter-speed data to establish the power function formula.

[0010] As another improvement of the present invention, the bonding force between the tin-based Babbitt alloy layer and the tile body is determined by tensile testing, and the bonding surface between the tin-based Babbitt alloy layer and the tile body is detected by ultrasonic testing and penetrant testing.

[0011] As another improvement of the present invention, the power function formula is based on regression fitting of the following inner diameter-speed data:

[0012] Inner diameter 200mm, rotation speed 500-520 rpm;

[0013] Inner diameter 250mm, rotation speed 440~460 rpm;

[0014] Inner diameter 300mm, rotation speed 390~410 rpm;

[0015] Inner diameter 350mm, rotation speed 350-370 rpm;

[0016] Inner diameter 400mm, rotation speed 320-340 rpm;

[0017] Inner diameter 450mm, rotation speed 300-320 rpm;

[0018] Inner diameter 500mm, rotation speed 290~310 rpm;

[0019] Inner diameter 550mm, rotation speed 275~295 rpm;

[0020] Inner diameter 600mm, rotation speed 260-280 rpm.

[0021] As another improvement of the present invention, the inner diameter-rotation speed data are regression-fitted using Origin software to establish the power function formula.

[0022] As another improvement of the present invention, the tin-based Babbitt alloy layer is made of ZSnSb11Cu6.

[0023] As another improvement of the present invention, the material of the tile body is steel.

[0024] As another improvement of the present invention, the method for calculating the centrifugal casting speed of tin-based bearing alloys is applied to the centrifugal casting process of sliding bearing bushes.

[0025] As another improvement of the present invention, the bonding force between the tin-based Babbitt alloy layer of the bearing and the bearing body reaches 40-60 MPa.

[0026] As another improvement of the present invention, samples were taken at 0°, 90°, 180° and 270° along the circumferential direction of the bearing to test the bonding force between the tin-based Babbitt alloy layer and the bearing body.

[0027] The beneficial effects of this invention are:

[0028] 1. This invention takes achieving a bonding force of 40–60 MPa between the tin-based Babbitt alloy layer and the bearing body as a direct constraint target, and establishes a quantitative power function relationship between rotational speed and the inner diameter of the bearing bush. This changes the traditional technical paradigm that relies solely on fluid dynamics forming or empirical criteria. Centrifugal casting using the rotational speed calculated by the formula of this invention results in a bearing bush with a bonding force stably controlled within the high-performance range of 40–60 MPa, solving the long-standing problem in existing technologies where bonding force cannot be used as a process design target.

[0029] 2. For the same bearing inner diameter, traditional formulas, such as the Bruzov formula and the Caiman formula, only provide a wide range of rotational speeds but cannot determine the optimal value, posing a serious dilemma for technicians. The formula of this invention can calculate a unique and definite rotational speed value for any given bearing inner diameter, which can be directly used to guide production, fundamentally overcoming the lack of process guidance in existing technologies.

[0030] 3. The rotational speed determined by the formula of this invention can generate sufficient centrifugal pressure on the molten alloy during centrifugal casting, enabling it to achieve sufficient feeding, compaction, and diffusion between atoms during the solidification stage, thereby obtaining a dense, continuous, and defect-free bonding interface. The bearing bushes cast using the method of this invention passed both ultrasonic and penetrant testing, verifying the consistency and reliability of the bonding surface quality.

[0031] 4. This invention condenses the complex multi-factor process optimization problem into a simple power function formula. Process engineers only need to measure the inner diameter of the bearing bush to quickly and accurately obtain the optimal centrifugal speed, without relying on trial and error or consulting multiple contradictory formulas. Batch testing has verified that the bonding force index at different sampling positions (0°, 90°, 180°, and 270°) is stable and has excellent reproducibility, making it widely applicable to the industrial centrifugal casting production of sliding bearing bushes of various specifications. Attached Figure Description

[0032] Figure 1This is a schematic diagram of the inner diameter-speed data regression fitting of the calculation method of centrifugal casting speed of tin-based bearing alloy according to the present invention. Detailed Implementation

[0033] The technical solutions in 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. Based on the embodiments of the present invention, all embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Specific implementation method one: Combining Figure 1 This embodiment describes a method for calculating the centrifugal casting speed of a tin-based bearing alloy, used for centrifugally casting a tin-based Babbitt alloy layer onto the inner surface of a bearing bush. The centrifugal casting speed is calculated using the following power function formula:

[0035] n=11058×R -0.582

[0036] In the formula, n is the rotational speed during centrifugal casting, in revolutions per minute; R is the inner diameter of the bearing, in millimeters.

[0037] The bearing bush, with an inner diameter of 320mm and made of 25# material, was centrifugally cast from ZSnSb11Cu6. The rotational speed, calculated using the formula of this invention, was 385 r / min. After casting, samples were taken at 0°, 90°, 180°, and 270° to check the bonding strength of the bearing alloy. The bonding strengths were 44.6MPa, 40.9MPa, 52.2MPa, and 53MPa, respectively. Ultrasonic and penetrant testing were performed on the bonding surfaces, and the results met the requirements.

[0038] Compared to existing formulas like the Bruzov formula and the Caiman formula, taking a 500mm inner diameter bearing bush cast with ZSnSb11Cu6 tin-based Babbitt alloy as an example: the Bruzov formula calculates speeds of 423–964 r / min, with the upper and lower limits differing by more than double, leaving process engineers bewildered; the Caiman formula calculates only 167–190 r / min. Experimental verification shows that bearing bush products cast within the speed ranges determined by these two formulas fail to meet the modern industrial requirement of 40–60 MPa for the bonding strength between the alloy layer and the steel backing. Defects such as peeling and porosity are present at the bonding surface, and ultrasonic and penetrant testing fail. Existing speed calculation formulas rely on molding or simple empirical criteria, failing to establish a quantitative relationship between speed and metallurgical bonding quality, thus becoming a bottleneck restricting the manufacturing quality of high-performance sliding bearing bushes.

[0039] This invention takes achieving a bonding force of 40–60 MPa between the tin-based Babbitt alloy layer and the bearing body as a direct constraint target, and establishes a quantitative power function relationship between rotational speed and the inner diameter of the bearing bush. This changes the traditional technical paradigm that relies solely on fluid dynamics forming or empirical criteria. Centrifugal casting using the rotational speed calculated by the formula of this invention results in a bearing bush with a bonding force stably controlled within the high-performance range of 40–60 MPa, solving the long-standing problem in existing technologies where bonding force cannot be used as a process design target.

[0040] For the same bearing inner diameter, traditional formulas, such as the Bruzov formula and the Caiman formula, only provide a wide range of rotational speeds but cannot determine the optimal value, posing a serious dilemma for technicians. The formula of this invention can calculate a unique and definite rotational speed value for any given bearing inner diameter, which can be directly used to guide production, fundamentally overcoming the lack of process guidance in existing technologies.

[0041] Specific Implementation Method Two: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that it involves centrifugal casting tests at different rotational speeds for tiles with different inner diameters to obtain rotational speed data that achieves a bonding force of 40–60 MPa between the tin-based Babbitt alloy layer and the tile body for each inner diameter. Regression fitting is then performed on the inner diameter-rotational speed data to establish the power function formula. Other components and connection methods are the same as in Specific Embodiment 1.

[0042] Specific implementation method three: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that the bonding force between the tin-based Babbitt alloy layer and the tile body is determined by a tensile test, and the bonding surface between the tin-based Babbitt alloy layer and the tile body is detected by ultrasonic testing and penetrant testing.

[0043] Specific implementation method four: Combination Figure 1 This embodiment differs from Specific Embodiment 1 in that the power function formula is based on regression fitting of the following inner diameter-speed data:

[0044] Inner diameter 200mm, rotation speed 500-520 rpm;

[0045] Inner diameter 250mm, rotation speed 440~460 rpm;

[0046] Inner diameter 300mm, rotation speed 390~410 rpm;

[0047] Inner diameter 350mm, rotation speed 350-370 rpm;

[0048] Inner diameter 400mm, rotation speed 320-340 rpm;

[0049] Inner diameter 450mm, rotation speed 300-320 rpm;

[0050] Inner diameter 500mm, rotation speed 290~310 rpm;

[0051] Inner diameter 550mm, rotation speed 275~295 rpm;

[0052] Inner diameter 600mm, rotation speed 260-280 rpm.

[0053] Specific Implementation Method Five: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that it uses Origin software to perform regression fitting on the inner diameter-rotation speed data to establish the power function formula.

[0054] Specific Implementation Method Six: Combination Figure 1 This embodiment differs from Specific Embodiment 1 in that the tin-based Babbitt alloy layer is made of ZSnSb11Cu6.

[0055] Specific implementation method seven: Combining Figure 1 This embodiment differs from specific embodiment one in that the material of the tile body is steel.

[0056] Specific implementation method eight: Combination Figure 1 This embodiment differs from Specific Embodiment 1 in that the method for calculating the centrifugal casting speed of a tin-based bearing alloy is applied to the centrifugal casting process of sliding bearing bushes.

[0057] Specific Implementation Method Nine: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that the bonding force between the tin-based Babbitt alloy layer of the bearing bush and the bearing body reaches 40-60 MPa.

[0058] Specific Implementation Method Ten: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that it involves sampling and testing the bonding force between the tin-based Babbitt alloy layer and the bearing body at 0°, 90°, 180°, and 270° along the circumferential direction of the bearing.

[0059] Starting from the final quality objective of "bonding force", this invention reveals through systematic experiments the objective law that the optimal centrifugal speed decreases with a specific power function as the inner diameter of the bearing bush. Based on this, a quantitative calculation formula that can be directly used for process design is established, thereby transforming a production problem that originally relied on trial and error and had contradictory formulas into a precise, unique and reproducible engineering solution.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the centrifugal casting speed of tin-based bearing alloys, used for centrifugally casting a tin-based Babbitt alloy layer on the inner surface of a bearing bush, characterized in that... The centrifugal casting speed is calculated using the following power function formula: n=11058×R -0.582 In the formula, n is the rotational speed during centrifugal casting, in revolutions per minute; R is the inner diameter of the bearing, in millimeters.

2. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 1, characterized in that, Centrifugal casting tests were conducted on tiles with different inner diameters at different rotational speeds to obtain rotational speed data that achieved a bonding force of 40–60 MPa between the tin-based Babbitt alloy layer and the tile body for each inner diameter. Regression fitting was performed on the inner diameter-rotational speed data to establish the power function formula.

3. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 2, characterized in that, The bonding force between the tin-based Babbitt alloy layer and the tile body was determined by tensile testing, and the bonding surface between the tin-based Babbitt alloy layer and the tile body was detected by ultrasonic testing and penetrant testing.

4. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 2, characterized in that, The power function formula is based on regression fitting of the following inner diameter-speed data: Inner diameter 200mm, rotation speed 500-520 rpm; Inner diameter 250mm, rotation speed 440~460 rpm; Inner diameter 300mm, rotation speed 390~410 rpm; Inner diameter 350mm, rotation speed 350-370 rpm; Inner diameter 400mm, rotation speed 320-340 rpm; Inner diameter 450mm, rotation speed 300-320 rpm; Inner diameter 500mm, rotation speed 290~310 rpm; Inner diameter 550mm, rotation speed 275~295 rpm; Inner diameter 600mm, rotation speed 260-280 rpm.

5. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 2, characterized in that, The power function formula was established by using Origin software to perform regression fitting on the inner diameter-rotation speed data.

6. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 1, characterized in that, The tin-based Babbitt alloy layer is made of ZSnSb11Cu6.

7. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 1, characterized in that, The tile body is made of steel.

8. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 1, characterized in that, The method for calculating the centrifugal casting speed of tin-based bearing alloys is applied to the centrifugal casting process of sliding bearing bushes.

9. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 8, characterized in that, The bonding strength between the tin-based Babbitt alloy layer of the bearing and the bearing body reaches 40-60 MPa.

10. The method for calculating the centrifugal casting speed of a tin-based bearing alloy according to claim 9, characterized in that, Samples were taken at 0°, 90°, 180° and 270° along the circumference of the bearing to test the bonding force between the tin-based Babbitt alloy layer and the bearing body.

Images