Method for calculating interference of copper alloy casting roll sleeve assembly
By establishing a mathematical model to calculate the assembly interference of copper alloy casting roll sleeves, the problems of circumferential movement and cooling water leakage in copper alloy casting roll sleeves during casting and rolling production were solved, thereby improving the precision and efficiency of casting and rolling production, expanding the range of alloy varieties, and reducing energy consumption.
Patent Information
- Application Number
- CN202210929501.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-04
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2042-08-04
AI Technical Summary
In the existing technology, the calculation of the interference fit of copper alloy casting and rolling roll sleeves lacks a scientific basis, which makes it easy for circumferential relative movement, water flow or leakage to occur in the casting and rolling production, affecting production efficiency and the quality of casting and rolling products.
By establishing a mathematical model, the torsional shear stress, average tangential thermal stress, and assembly shear stress of the copper alloy cast and rolled roll sleeve are calculated. A reasonable assembly interference is determined to ensure that the copper roll sleeve and the steel roll core do not experience circumferential relative movement or cooling water leakage during the casting and rolling process. The torque is transmitted by using an interference fit.
It has improved the precision and efficiency of casting and rolling production, expanded the range of alloy varieties, reduced production energy consumption, and enhanced the economic benefits of casting and rolling products.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of casting roll assembly technology, specifically a method for calculating the interference fit of copper alloy casting roll assembly. Background Technology
[0002] Existing cobalt-beryllium bronze roller sleeves and rare-earth element copper roller sleeves are copper alloy roller sleeves specifically developed for continuous casting and rolling mills of aluminum strip. Compared with cast and rolled steel roller sleeves, copper roller sleeves have higher thermal conductivity, with a thermal conductivity 8-10 times that of steel roller sleeves. This advantage allows for a significant increase in casting and rolling speed, a denser microstructure in the cast and rolled strip, and an expansion of the range of alloy varieties that can be produced.
[0003] Existing copper alloy cast rolling mill sleeves mainly consist of a copper sleeve, a steel core, a water trough, and inlet and outlet water holes. The cooling water holes adopt a one-inlet, three-outlet structure. The inlet and outlet water holes are evenly and alternately arranged in the water trough to ensure that every part of the roll surface has the same cooling intensity. The cooling water temperature is 30-40℃, and the temperature difference between the inlet and outlet is 1-3℃. The sleeve and core only mate along the surface of the water trough, and the contact area accounts for only 2 / 5 of the entire inner roll surface. Therefore, the machining accuracy requirements for the core surface and the inner surface of the sleeve are very high to ensure the uniform distribution of interference fit stress.
[0004] The copper roll sleeve is based on the steel roll core and uses an interference fit. On the one hand, it seals the water tank to prevent cooling water leakage. On the other hand, it transmits the required torque when bearing rolling load. It ensures that when the rolling load reaches the maximum allowable value, the roll sleeve and the corresponding position of the roll core assembly will have a small circumferential displacement and will no longer move relative to each other.
[0005] The main objective of this invention is to study the interference fit when assembling two different materials, steel roller core and copper roller sleeve, and to propose a method for determining the interference fit of copper alloy cast rolling roll sleeve assembly, providing a scientific reference for the promotion and application of copper roller sleeve technology in my country. Summary of the Invention
[0006] To achieve the above technical effects, the method for calculating the interference fit of a copper alloy cast roll assembly according to the present invention does not include the following steps:
[0007] S1. It is assumed that the assembled copper roll sleeve and steel roll core will not undergo circumferential relative movement or roll expansion during the casting and rolling process, and the sum of the torsional shear stress and the average tangential thermal stress during the casting and rolling process is equal to the assembly shear stress.
[0008] S2. Under the conditions of step S1, the torsional shear stress generated by the rolling torque output on the copper roll sleeve casting roll. The calculation formula is:
[0009] ;
[0010] In the formula:
[0011] S3. Under the conditions of step S1, the average tangential thermal stress experienced by the copper roll sleeve during the casting and rolling process, under steady heat flow without an internal heat source, is the average tangential thermal stress. The calculation formula is:
[0012] ;
[0013] S4. Calculate the corresponding assembly shear stress based on steps S2 and S3. , The calculation formula is:
[0014] ;
[0015] S5. Calculate assembly stress , The calculation formula is:
[0016] ;
[0017] S6. Copper alloy roller set with interference fit The calculation formula is:
[0018] ;
[0019] In the formulas for steps S1-S6: T is the rolling torque; The inner diameter of the roller sleeve; The outer diameter of the roller sleeve; The Poisson's ratio of the roller sleeve material; The Poisson's ratio of the roller core material; The elastic modulus of the roller sleeve material; The elastic modulus of the roller core material; The temperature difference between the outside and inside of the copper roller sleeve in the casting and rolling zone; is the coefficient of thermal expansion.
[0020] Furthermore, in step S1 above, the assembled copper roll sleeve and steel roll core do not undergo circumferential relative movement during casting and rolling production, and there is no water leakage or cross-flow, nor is there a large interference fit during assembly.
[0021] Furthermore, in step S3 above, the average tangential thermal stress is calculated under steady heat flow conditions based on the tangential thermal stress at the center of the wall thickness during online production of the roller sleeve.
[0022] Furthermore, in step S4 above, the magnitude of the assembly shear stress of the roll sleeve is determined by the torsional shear stress and the average tangential thermal stress of the roll sleeve during casting and rolling production. Under the condition of ensuring that the roll does not shift, the assembly shear stress must not be less than the sum of the two.
[0023] Furthermore, in step S5 above, the assembly stress during the assembly process of the copper roller assembly is calculated by reverse derivation based on the relationship between assembly stress and assembly shear stress.
[0024] Furthermore, in S6 above, the inner and outer diameters of the roller sleeve are based on the final dimensions when the new roller is assembled, and are the average values of 5 points, with a taper and roundness of less than 0.05 mm.
[0025] The beneficial effects of this invention are as follows: This invention constructs a mathematical model and calculation method for the interference fit of copper alloy roll sleeves, including the following steps: S1. The sum of torsional shear stress and average tangential thermal stress during the casting and rolling process equals the assembly shear stress; S2. Calculate the torsional shear stress; S3. Calculate the average tangential thermal stress; S4. Calculate the assembly shear stress; S5. Assembly stress; S6. Copper alloy roll sleeve interference fit; including the construction of mathematical models for torsional shear stress, average tangential thermal stress, and assembly shear stress, exploring their influence on the interference fit of copper alloy casting and rolling roll sleeves. The method of this invention serves as the basis for determining the interference fit, which is scientific and reasonable, promotes the assembly accuracy of copper alloy roll sleeves, improves the efficiency of casting and rolling production, and applies the method of this invention to copper alloy roll sleeve materials with high thermal conductivity to increase the solidification rate of aluminum melt, thereby increasing the casting and rolling production speed and expanding the range of casting and rolling alloy products, reducing production energy consumption, and significantly improving the economic benefits of casting and rolling product production. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the structure of the copper alloy casting roll of the present invention.
[0027] In the diagram: 1. Water tank; 2. Copper roller sleeve; 3. Steel roller core; 4. Water outlet; 5. Water inlet. Detailed Implementation
[0028] The method for calculating the interference fit of a copper alloy cast roll assembly according to the present invention does not include the following steps:
[0029] S1. It is assumed that the assembled copper roll sleeve and steel roll core will not undergo circumferential relative movement or roll expansion during the casting and rolling process, and the sum of the torsional shear stress and the average tangential thermal stress during the casting and rolling process is equal to the assembly shear stress.
[0030] S2. Under the conditions of step S1, the torsional shear stress generated by the rolling torque output on the copper roll sleeve casting roll. The calculation formula is:
[0031] ;
[0032] In the formula:
[0033] S3. Under the conditions of step S1, the average tangential thermal stress experienced by the copper roll sleeve during the casting and rolling process, under steady heat flow without an internal heat source, is the average tangential thermal stress. The calculation formula is:
[0034] ;
[0035] S4. Calculate the corresponding assembly shear stress based on steps S2 and S3. , The calculation formula is:
[0036] ;
[0037] S5. Calculate assembly stress , The calculation formula is:
[0038] ;
[0039] S6. Copper alloy roller set with interference fit The calculation formula is:
[0040] ;
[0041] In the formulas for steps S1-S6: T is the rolling torque; The inner diameter of the roller sleeve; The outer diameter of the roller sleeve; The Poisson's ratio of the roller sleeve material; The Poisson's ratio of the roller core material; The elastic modulus of the roller sleeve material; The elastic modulus of the roller core material; The temperature difference between the outside and inside of the copper roller sleeve in the casting and rolling zone; is the coefficient of thermal expansion.
[0042] Furthermore, in step S1 above, the assembled copper roll sleeve and steel roll core do not undergo circumferential relative movement during casting and rolling production, and there is no water leakage or cross-flow, nor is there a large interference fit during assembly.
[0043] Furthermore, in step S3 above, the average tangential thermal stress is calculated under steady heat flow conditions based on the tangential thermal stress at the center of the wall thickness during online production of the roller sleeve.
[0044] Furthermore, in step S4 above, the magnitude of the assembly shear stress of the roll sleeve is determined by the torsional shear stress and the average tangential thermal stress of the roll sleeve during casting and rolling production. Under the condition of ensuring that the roll does not shift, the assembly shear stress must not be less than the sum of the two.
[0045] Furthermore, in step S5 above, the assembly stress during the assembly process of the copper roller assembly is calculated by reverse derivation based on the relationship between assembly stress and assembly shear stress.
[0046] Furthermore, in S6 above, the inner and outer diameters of the roller sleeve are based on the final dimensions during the assembly of the new roller, and are the average values of five equally spaced points, with a taper and roundness of less than 0.05 mm. Roller sleeve inner diameter The calculation formula is Roller sleeve outer diameter The calculation formula is: .
[0047] like Figure 1 As shown, the copper alloy cast rolling roll sleeve includes a copper roll sleeve 2 and a steel roll core 3. The steel roll core 3 is inserted into the copper roll sleeve 2. The steel roll core 3 is provided with a water groove 1, a water outlet 4, and a water inlet 5. The cooling water holes adopt a one-in-three-out structure. The water inlet and outlet holes are evenly and alternately arranged in the water groove to ensure that every part of the roll surface has the same cooling intensity. The cooling water temperature is 30-40℃, and the temperature difference between the inlet and outlet is 1-3℃. The roll sleeve and the roll core only fit along the surface of the water groove, and the contact part only occupies 2 / 5 of the entire inner roll surface. Therefore, the machining accuracy requirements for the surface of the roll core and the inner surface of the roll sleeve are very high to ensure the uniform distribution of interference fit stress. The copper roll sleeve uses the steel roll core as a reference and adopts interference fit. On the one hand, it seals the water groove to prevent cooling water leakage. On the other hand, it transmits the required torque when bearing the rolling load. It ensures that when the rolling load reaches the maximum allowable value, the corresponding positions of the roll sleeve and the roll core assembly will have a small circumferential displacement and will no longer move relative to each other.
[0048] Example 1:
[0049] Taking a Φ850×1700mm cast roll as an example, the roll sleeve material is cobalt bronze, the roll core material is 42CrMo, and the relevant parameters of the cast roll are shown in the table below.
[0050] Table 1. Roll materials and their mechanical properties:
[0051] .
[0052] In actual production, the temperature difference between the inside and outside of the casting and rolling mill roll sleeve can be controlled by adjusting the temperature of the front box and the cooling water. However, the control range is limited, resulting in little change in the average tangential thermal stress. Therefore, in most cases, the rolling torque is set to verify the effectiveness of the selected assembly interference. When using copper rolls, it is recommended that the rolling torque not exceed 75% of the rated torque.
[0053] The maximum rolling torque of the Φ850×1700mm casting and rolling mill is T=330kN.m, and the inner diameter of the copper roll sleeve is... outer diameter of copper roller sleeve Cooling water temperature 35℃, temperature difference between the outside and inside of the copper roll sleeve in the casting and rolling zone. Coefficient of thermal expansion of copper roller sleeve .
[0054] The torsional shear stress is calculated by the steps of this invention. Mean tangential thermal stress Assembly shear stress Assembly stress Assembly interference fit .
[0055] Example 2:
[0056] The roll material and its mechanical properties are the same as in Example 1. The maximum rolling torque of the Φ850×1700mm casting and rolling mill is T=330kN.m, and the inner diameter of the copper roll sleeve is... outer diameter of copper roller sleeve Cooling water temperature 25℃, temperature difference between the outside and inside of the copper roll sleeve in the casting and rolling zone. Coefficient of thermal expansion of copper roller sleeve .
[0057] The torsional shear stress is calculated by the steps of this invention. Mean tangential thermal stress Assembly shear stress Assembly stress Assembly interference fit .
[0058] Example 3:
[0059] The roll material and its mechanical properties are the same as in Example 1. The rolling torque of the Φ850×1700mm casting and rolling mill is T=330×75%=247.5kN.m, and the inner diameter of the copper roll sleeve is... outer diameter of copper roller sleeve Cooling water temperature 35℃, temperature difference between the outside and inside of the copper roll sleeve in the casting and rolling zone. Coefficient of thermal expansion of copper roller sleeve .
[0060] The torsional shear stress is calculated by the steps of this invention. Mean tangential thermal stress Assembly shear stress Assembly stress Assembly interference fit .
[0061] Example 4:
[0062] The roll material and its mechanical properties are the same as in Example 1. The rolling torque of the Φ850×1700mm casting and rolling mill is T=330×75%=247.5kN.m, and the inner diameter of the copper roll sleeve is... outer diameter of copper roller sleeve Cooling water temperature 25℃, temperature difference between the outside and inside of the copper roll sleeve in the casting and rolling zone. Coefficient of thermal expansion of copper roller sleeve .
[0063] The torsional shear stress is calculated by the steps of this invention. Mean tangential thermal stress Assembly shear stress Assembly stress Assembly interference fit .
[0064] Calculations in Examples 1, 2, 3, and 4 show that the selection of the interference fit for the copper roll sleeve is significantly influenced by rolling torque, material elastic modulus, coefficient of thermal expansion, wall thickness, and temperature difference between the inside and outside of the roll sleeve. Calculations reveal that the assembly shear stress of the copper roll sleeve reaches more than 10 times the torsional shear stress. This is primarily because the copper roll sleeve undergoes continuous and periodic contact with the high-temperature molten aluminum alloy during production, generating substantial tangential thermal stress.
[0065] In summary, to prevent excessive rolling torque during production, which could affect the lifespan of the copper rolls, and to prevent circumferential movement after the roll sleeve and roll core are assembled, the ideal interference fit for a Φ850×1700mm copper roll sleeve cast roll is 1.29-1.46mm, meaning the hot-fit interference fit of the copper roll sleeve is controlled between 0.176% and 2.0%.
Claims
1. A method for calculating the interference fit of a copper alloy cast roll assembly, wherein the copper alloy cast roll includes a copper roll sleeve (2) and a steel roll core (3), the steel roll core (3) being inserted into the copper roll sleeve (2), and the steel roll core (3) being provided with a water groove (1), a water outlet (4) and a water inlet (5), characterized in that: The steps include the following: S1. It is assumed that the assembled copper roll sleeve and steel roll core will not undergo circumferential relative movement or roll expansion during the casting and rolling process, and the sum of the torsional shear stress and the average tangential thermal stress during the casting and rolling process is equal to the assembly shear stress. S2. Under the conditions of step S1, the torsional shear stress generated by the rolling torque output on the copper roll sleeve casting roll. The calculation formula is: ； S3. Under the conditions of step S1, the average tangential thermal stress experienced by the copper roll sleeve during the casting and rolling process, under steady heat flow without an internal heat source, is the average tangential thermal stress. The calculation formula is: ； S4. Calculate the corresponding assembly shear stress based on steps S2 and S3. , The calculation formula is: ； S5. Calculate assembly stress , The calculation formula is: ； S6. Copper alloy roller set with interference fit The calculation formula is: ； In the formulas for steps S1-S6: T is the rolling torque; The inner diameter of the roller sleeve; The outer diameter of the roller sleeve; The Poisson's ratio of the roller sleeve material; The Poisson's ratio of the roller core material; The elastic modulus of the roller sleeve material; The elastic modulus of the roller core material; The temperature difference between the outside and inside of the copper roller sleeve in the casting and rolling zone; is the coefficient of thermal expansion.
2. The method for calculating the interference fit of a copper alloy cast roll assembly according to claim 1, characterized in that: In step S1 above, the assembled copper roller sleeve and steel roller core do not move circumferentially relative to each other during casting and rolling production, and there is no water leakage or cross-flow, nor is there a large interference fit during assembly.
3. The method for calculating the interference fit of a copper alloy cast roll assembly according to claim 1, characterized in that: In step S3 above, the average tangential thermal stress is calculated under steady heat flow conditions based on the tangential thermal stress at the center of the wall thickness during online production of the roller sleeve.
4. The method for calculating the interference fit of a copper alloy cast roll assembly according to claim 1, characterized in that: In step S4 above, the magnitude of the assembly shear stress of the roll sleeve is determined by the torsional shear stress and the average tangential thermal stress of the roll sleeve during casting and rolling production. Under the premise of ensuring that the roll does not shift, the assembly shear stress must not be less than the sum of the two.
5. The method for calculating the interference fit of a copper alloy cast roll assembly according to claim 1, characterized in that: In step S5 above, the assembly stress during the assembly process of the copper roller assembly is calculated by reverse derivation based on the relationship between assembly stress and assembly shear stress.
6. The method for calculating the interference fit of a copper alloy cast roll assembly according to claim 1, characterized in that: In S6 above, the inner and outer diameters of the roller sleeve are based on the final dimensions when the new roller is assembled. They are the average values of 5 points, and their taper and roundness are both less than 0.05 mm.