Method for designing thickness of water tank type continuous casting crystallizer

Abstract

The invention provides a method for designing the thickness of a water tank type continuous casting crystallizer, which relates to the technical field of continuous casting of billets and comprises the following steps of: 1, determining the hot surface temperature Thot of the crystallizer according to the material of the crystallizer; 2, preliminarily presetting the width wc, the depth dc and the distance pc of a crystallizer cooling water tank, and calculating the equivalent heat exchange coefficient hw of the crystallizer water tank; and 3, calculating the total thickness dmold of the crystallizer. The method for calculating the thickness of the crystallizer is reduced to three steps, and the defects that an existing method is complex in calculation and long in process are overcome. The method is simple and fast, time can be effectively saved, and production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steel billet continuous casting, and in particular to a design method for the thickness of a water tank type continuous casting crystallizer. Background Art

[0002] Billet continuous casting technology is one of the indispensable links in steel smelting. As the core equipment, the water tank crystallizer has a vital impact on the quality and production efficiency of the billet. The molten steel solidifies into a billet shell in the crystallizer, and then forms a qualified ingot. The crystallizer is in direct contact with the molten steel and cooling water. The design of the crystallizer is directly related to the cooling effect and surface quality of the ingot. Therefore, it is necessary to reasonably design the thickness of the crystallizer according to different smelting conditions.

[0003] Existing methods for calculating mold thickness include calculation formulas based on pressure bearing capacity, empirical formulas, and simulation analysis based on material mechanical properties. However, these methods have the disadvantages of complex calculations and lengthy processes, making it difficult to quickly and efficiently obtain accurate wall thickness calculation results. Summary of the invention

[0004] The problem solved by the invention is how to simply and quickly design the thickness of the crystallizer.

[0005] In order to solve the above problems, the present invention provides a method for designing the thickness of a water tank type continuous casting crystallizer.

[0006] The present invention provides a method for designing the thickness of a water tank type continuous casting crystallizer, comprising the following steps:

[0007] The first step is to determine the hot surface temperature T of the crystallizer according to the material of the crystallizer. hot ;

[0008] The second step is to preliminarily set the width w of the crystallizer cooling water tank c , depth d c and spacing p c , according to the width w of the cooling water tank c , depth d c and spacing p c , calculate the equivalent heat transfer coefficient h of the crystallizer water tank w ;

[0009] The third step is to calculate the overall thickness d of the crystallizer according to the following formula mold :

[0010]

[0011] In the above formula, k mold is the thermal conductivity of the crystallizer, T w0 is the temperature of cooling water; is the average heat flux density of the crystallizer.

[0012] Compared with the prior art, the design method of the thickness of the water tank type continuous casting crystallizer of the present invention has the following beneficial effects:

[0013] The present invention reduces the calculation method of the crystallizer thickness to three steps. The crystallizer of suitable material is selected according to the smelting requirements and conditions, and the width w of the crystallizer cooling water tank is preset. c , depth d c and spacing p c , the equivalent heat transfer coefficient h can be obtained in one step w , and then by the formula

[0014]

[0015] The thickness of the crystallizer is obtained. The calculation method is simple and fast, which can effectively save time and improve production efficiency.

[0016] Optionally, in the first step, the hot surface temperature T hot Below the recrystallization temperature of the mold material.

[0017] Through the above technical solution, the hot surface temperature T is set hot It must be lower than the recrystallization temperature of the crystallizer material to protect the molecular structure of the crystallizer surface from damage and extend the service life of the crystallizer.

[0018] Optionally, when the crystallizer is made of silver-copper alloy, the recrystallization temperature is 300°C, and the cold surface temperature of the crystallizer is T cold The maximum temperature is 100℃.

[0019] Through the above technical solution, the cost of silver-copper alloy is relatively high, so that the cold surface temperature T cold Keeping the temperature below 100°C can avoid the crystallizer from exploding and being damaged due to over-temperature, thus extending the service life of the equipment.

[0020] Optionally, in the second step, the cooling water tank on the cold surface of the crystallizer is a fin structure, and the equivalent heat transfer coefficient of the fin structure crystallizer water tank is h w , calculated using the following formula:

[0021]

[0022] In the above formula, h water is the heat transfer coefficient between the crystallizer and cooling water, calculated using the Nusselt number Nu:

[0023]

[0024] In the above formula, w c is the width of the cooling water tank;

[0025] dc is the depth of the cooling water tank;

[0026] p c is the spacing of cooling water tanks.

[0027] Through the above technical solution, the cooling water tank on the cold surface of the crystallizer is set as a fin structure, which can increase the convection heat transfer area, thereby improving the convection heat transfer coefficient between the water channel and water, thereby improving the cooling efficiency.

[0028] Optionally, in the third step, the temperature of the cooling water is T w0 is 25℃.

[0029] Through the above technical solution, room temperature cooling water has a high cost-effectiveness ratio and has the advantages of low cost, easy availability and availability compared to other cooling media.

[0030] Optionally, a fourth step is included, according to the thickness d of the crystallizer in the third step. mold And the second step presets the width w of the crystallizer cooling water tank c , depth d c and spacing p c , establish a three-dimensional model, and perform finite element analysis to obtain the temperature distribution data inside the crystallizer.

[0031] Through the above technical solution, according to the crystallizer thickness calculated by the first three steps and the crystallizer width w preset in the second step c , depth d c , spacing p c The establishment of a three-dimensional model can simulate the specific temperature distribution inside the crystallizer under the current thickness, width, depth and spacing in production, and judge whether the preset crystallizer size parameters in the second step are reasonable based on the uniformity of the temperature distribution.

[0032] Optionally, in the fourth step, when the temperature distribution inside the crystallizer is uniform, the crystallizer thickness d mold Meet the design requirements; otherwise repeat steps 2 to 4 until the analyzed mold thickness d mold Meet design requirements.

[0033] Through the above technical scheme, iterative back calculation is performed according to the temperature distribution obtained in the fourth step. In addition to calculating the thickness of the crystallizer, more accurate crystallizer width, depth and spacing parameters can be obtained according to the temperature distribution of the crystallizer, thereby achieving a more comprehensive and comprehensive optimization design of the crystallizer while meeting the requirements of efficient cooling, durability and cost-effectiveness.

[0034] Optionally, the crystallizer is made of copper alloy.

[0035] Through the above technical solution, the copper alloy can not only withstand the combined effects of high temperature, high pressure and mechanical stress, but also has good thermal conductivity, wear resistance and corrosion resistance.

[0036] Optionally, the crystallizer is made of chromium-zirconium-copper alloy.

[0037] Through the above technical solution, the chromium-zirconium-copper alloy not only has high strength and hardness, but also has excellent thermal conductivity and corrosion resistance, and is suitable for the continuous casting production of large square billets.

[0038] Optionally, the crystallizer is made of silver-copper alloy.

[0039] Through the above technical scheme, the silver-copper alloy has good thermal conductivity and thermal fatigue resistance, and is suitable for the continuous casting production of round billets. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a step diagram of the design method of the thickness of the water tank type continuous casting crystallizer according to an embodiment of the present application.

[0041] Figure 2 This is a temperature distribution diagram of the crystallizer water tank obtained by using the method of the embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0043] The Z axis in the drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z axis represents the top, and the reverse direction of the Z axis represents the bottom; the X axis in the drawings represents the horizontal direction, and is designated as the front and back position, and the positive direction of the X axis represents the front side, and the reverse direction of the X axis represents the back side; the Y axis in the drawings represents the left and right position, and the positive direction of the Y axis represents the left side, and the reverse direction of the Y axis represents the right side. It should also be noted that the aforementioned Z axis, Y axis, and X axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0044] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0045] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0046] In the related art, the traditional crystallizer thickness design method has the disadvantages of complex calculation and lengthy process, and it is difficult to quickly and efficiently obtain accurate wall thickness calculation results. It is difficult to simultaneously meet the requirements of efficient cooling, durability and cost-effectiveness.

[0047] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a method for designing the thickness of a water tank type continuous casting crystallizer.

[0048] like Figure 1 As shown, a method for designing the thickness of a water tank type continuous casting crystallizer provided in an embodiment of the present invention comprises the following steps:

[0049] The first step is to determine the hot surface temperature T of the crystallizer according to the material of the crystallizer. hot .

[0050] In order to avoid the explosion caused by film boiling and nucleate boiling of cooling water in the water tank, the hot surface temperature T hot The cold surface temperature T must be lower than the recrystallization temperature of the mold material and determined according to the cooling water requirements. cold The threshold value of the cold surface temperature T cold The temperature is controlled below the boiling point of the cooling water to avoid explosion caused by film boiling and nucleate boiling of the cooling water in the water tank, and the production safety is improved by controlling the temperature.

[0051] The preferred material for the crystallizer is copper alloy, which can not only withstand the combined effects of high temperature, high pressure and mechanical stress, but also has good thermal conductivity, wear resistance and corrosion resistance, which can greatly improve the overall performance of the equipment.

[0052] In the continuous casting production of large square billets, the crystallizer is preferably made of chromium-zirconium-copper alloy. Chromium-zirconium-copper alloy not only has high strength and hardness, but also has excellent thermal conductivity and corrosion resistance.

[0053] In the continuous casting production of round billets, silver-copper alloy crystallizers are preferred. Silver-copper alloy has good thermal conductivity and thermal fatigue resistance. Due to the high cost of silver-copper alloy, the cold surface temperature T cold Not higher than 100°C, in addition to the safety effect, it can also avoid the crystallizer from exploding and being damaged due to over-temperature, thereby extending the service life of the equipment. cold Equal to the cooling water temperature.

[0054] The second step is to preliminarily set the width w of the crystallizer cooling water tank c , depth d c and spacing p c , calculate the equivalent heat transfer coefficient h of the crystallizer water tank w .

[0055] like Figure 2 As shown, it is worth noting that in this embodiment, the cooling water tank of the crystallizer is set as a fin structure, and multiple water tanks are arranged inside. The fin structure can realize that the airflow contacts the liquid multiple times and collides with the inside of the fin, and the airflow is exchanged with heat, thereby providing a more stable low-temperature gas supply at a lower cost. This W-shaped fin design not only increases the heat exchange area, but also enhances the heat exchange efficiency through the internal water tank design, making the cooling effect more efficient and stable.

[0056] The equivalent heat transfer coefficient h of the fin structure crystallizer water tank w , calculated using the following formula:

[0057]

[0058] In the above formula, k mold is the thermal conductivity of the crystallizer;

[0059] h water is the heat transfer coefficient between the crystallizer and cooling water, calculated using the Nusselt number Nu:

[0060]

[0062] In the above formula, w c is the width of the cooling water tank;

[0063] d c is the depth of the cooling water tank;

[0064] p c is the spacing of cooling water tanks.

[0065] The third step is to calculate the overall thickness d of the crystallizer according to the following formula mold :

[0066]

[0067] In the above formula, T w0 is the temperature of cooling water;

[0068] is the average heat flux density of the crystallizer, which is calculated by the water volume of the crystallizer, the temperature difference between the inlet and outlet, and the specific heat capacity of water. It is a conventional calculation formula for continuous casting and will not be repeated here.

[0069] Cooling water temperature T w0 The preferred temperature is 25° C. Cooling water at room temperature is cost-effective and has the advantages of low cost, easy availability, and availability compared to other cooling media.

[0070] The present invention reduces the calculation method of the crystallizer thickness to three steps. The crystallizer of suitable material is selected according to the smelting requirements and conditions, and the width w of the crystallizer cooling water tank is preset. c , depth d c and spacing p c , the equivalent heat transfer coefficient h can be obtained in one step w , and then by the formula

[0071]

[0072] The thickness of the crystallizer is calculated. The calculation method is simple and quick, which can effectively save time and improve production efficiency.

[0073] The following is a further explanation of this method based on specific experimental data:

[0074] Step 1: Select a crystallizer made of silver-copper alloy. T hot =300℃, cooling water uses 25℃ normal temperature water, T cold =25℃, the thermal physical parameters of water are commonly used values ​​and will not be repeated here.

[0075] Step 2: Assume the tank size is width w c =5mm, depth d c =16mm and spacing p c =17.7mm.

[0076] After calculations in the second and third steps, the total thickness of the mold d mold ≈35.1mm.

[0077] In addition, after completing the first to third steps above, the crystallizer thickness d is obtained. mold After that, the following steps can be continued to perform a more comprehensive and optimized design of the crystallizer.

[0078] like Figure 1 Specifically, the method further comprises a fourth step, which specifically comprises: calculating the mold thickness d according to the crystallizer thickness d calculated in the third step. mold The width w of the crystallizer cooling water tank preset in the second step c , depth d c , spacing p c , build a three-dimensional model to simulate the specific temperature distribution inside the crystallizer under the current thickness, width, depth and spacing in production; and perform finite element analysis to obtain the temperature distribution data inside the crystallizer. The uniformity of the temperature distribution is used to determine whether the preset crystallizer size parameters in the second step are reasonable.

[0079] For example, according to the total thickness d of the above-mentioned crystallizer mold ≈35.1mm, width w c =5mm, depth d c =16mm and spacing p c =17.7mm, and perform three-dimensional modeling. Figure 2 This is the temperature distribution diagram of the crystallizer water tank obtained by simulation.

[0080] like Figure 2 As shown, at this time, the temperature fluctuation at the same depth is small, and the overall temperature gradient is reasonably and evenly distributed, so it can meet the use requirements.

[0081] In this embodiment, the cold surface temperature is 25°C, which meets the condition of not higher than 100°C, and the temperature distribution inside the crystallizer is uniform, which shows that the preset crystallizer size parameters are reasonable. mold Meet design requirements.

[0082] Otherwise, repeat steps 2 to 4 until the mold thickness d mold Meet design requirements.

[0083] By iteratively back-calculating the temperature distribution obtained in the fourth step, in addition to calculating the thickness of the crystallizer, this method can also obtain more accurate and more satisfactory crystallizer width, depth and spacing parameters according to the temperature distribution of the crystallizer, thereby achieving a more comprehensive and comprehensive optimization design of the crystallizer while meeting the requirements of efficient cooling, durability and cost-effectiveness.

[0084] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for designing the thickness of a water tank continuous casting crystallizer, characterized in that: The following steps are involved: The first step is to determine the hot surface temperature T of the crystallizer according to the material of the crystallizer. hot ; The second step is to preliminarily set the width w of the crystallizer cooling water tank c , depth d c and spacing p c , according to the width w of the cooling water tank c , depth d c and spacing p c , calculate the equivalent heat transfer coefficient h of the crystallizer water tank w ; The third step is to calculate the overall thickness d of the crystallizer according to the following formula mold : thickness In the above formula, k mold is the thermal conductivity of the crystallizer; T w0 is the temperature of cooling water; is the average heat flux density of the crystallizer.

2. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 1, characterized in that: In the first step, the hot surface temperature T hot Below the recrystallization temperature of the mold material.

3. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 2, characterized in that: When the crystallizer is made of silver-copper alloy, the recrystallization temperature is 300°C. At this time, the cold surface temperature of the crystallizer is T cold The maximum temperature is 100℃.

4. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 1, characterized in that: In the second step, the cooling water tank on the cold surface of the crystallizer is a fin structure, and the equivalent heat transfer coefficient of the fin structure crystallizer water tank is h w , calculated using the following formula In the above formula, h water is the heat transfer coefficient between the crystallizer and cooling water, calculated using the Nusselt number Nu In the above formula, w c is the width of the cooling water tank; d c is the depth of the cooling water tank; p c is the spacing of cooling water tanks.

5. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 1, characterized in that: In the third step, the cooling water temperature T w0 is 25℃.

6. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 1, characterized in that: The fourth step is to: according to the thickness d of the crystallizer in the third step mold And the second step presets the width w of the crystallizer cooling water tank c , depth d c and spacing p c , establish a three-dimensional model, and perform finite element analysis to obtain the temperature distribution data inside the crystallizer.

7. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 6, characterized in that: In the fourth step, when the temperature distribution inside the crystallizer is uniform, the crystallizer thickness d mold Meet the design requirements; otherwise repeat steps 2 to 4 until the analyzed mold thickness d mild Meet design requirements.

8. The method for designing the thickness of a water tank continuous casting crystallizer according to any one of claims 1 to 7, characterized in that: The crystallizer is made of copper alloy.

9. The method for designing the thickness of a water tank continuous casting crystallizer according to claim 8, characterized in that: The crystallizer is made of chromium-zirconium-copper alloy.

10. The method for designing the thickness of a water tank continuous casting mold according to claim 8, characterized in that: The crystallizer is made of silver-copper alloy.

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