A post-rolling controlled cooling device and method for precision alloy hot-rolled strip

Abstract

The application discloses a post-rolling controlled cooling device and method for precision alloy hot-rolled strip blanks, and the device comprises a quenching water tank, a water conveying pipeline, a cooling box, a water pump and a temperature and flow rate adjusting unit; the water inlet of the water conveying pipeline is arranged at one end of the quenching water tank, and the water inlet side of the water conveying pipeline is sequentially provided with the cooling box and the temperature and flow rate adjusting unit; the water outlet of the water conveying pipeline is arranged at the other end of the quenching water tank, and the water outlet side of the water conveying pipeline is provided with the water pump; the cooling medium is arranged in the cooling box and is used for cooling the water inlet of the water conveying pipeline; the temperature and flow rate adjusting unit obtains the current water temperature and adjusts the flow rate in the water conveying pipeline according to the water temperature. The number of ice blocks used for cooling of the device is controllable, the temperature constancy of the ice-water mixture is fully utilized, the flow rate and flow speed of the circulating water are controlled, the water temperature is controlled in real time, the automatic adjustment of the water temperature is realized, the water temperature of different positions in the water tank is uniform and stable, and the quenching of the hot-rolled strip blanks is uniform and the hardening effect is better.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and in particular to a post-rolling controlled cooling device and method for precision alloy hot-rolled strip billets. Background Technology

[0002] Traditional precision alloys are generally based on Fe, with the addition of various alloying elements such as Ni, Co, Cr, Al, Si, Ti, and Al to impart various special physical properties, including magnetic, elastic, expansion, and resistance / thermal properties. Examples include FeNi, FeCo, and FeAl series magnetic alloys, FeNi series elastic and expansion alloys, and NiCr series resistance / thermal alloys. These alloys typically undergo an ordered transformation or precipitation of strengthening phases between 400 and 800°C. This transformation is very rapid and can cause the alloy to become embrittled or hardened, making further cold rolling difficult.

[0003] Hot rolling is a crucial intermediate process in precision alloy production. To suppress ordered transformation or precipitation of strengthening phases during the cooling process of the hot-rolled strip, avoid the phase transformation temperature range, soften the strip, and improve its workability, the hot-rolled strip must be cooled at a sufficiently fast rate. In production, to improve cooling speed and hardenability, an ice-water mixture is typically used as the refrigerant. This process requires breaking ice into small pieces and adding them to a water tank to form the ice-water mixture. However, the ice pieces vary in size and float on the surface. When the steel strip enters the water, the ice blocks provide support, hindering its entry and slowing down the process. As the number of quenched strips increases, despite the continuous addition of ice, the overall water temperature tends to rise, resulting in inconsistent and uncontrollable temperatures across different parts of the tank. These factors lead to uneven strip cooling, poor hardenability, inability to completely suppress the precipitation of strengthening phases or ordered transformation, significant performance differences between different parts of the strip, and a high risk of strip breakage during subsequent cold rolling. In addition, the method of crushing ice first and then adding it to the water tank is not only labor-intensive and time-consuming, but also makes the quantity of ice uncontrollable, which increases production costs. Summary of the Invention

[0004] Based on this, the present application provides a post-rolling controlled cooling device and method for precision alloy hot-rolled strip billets, which can effectively address the problems of uncontrollable water temperature, uneven quenching, poor effect, high cost, and low efficiency in the current process of continuously adding ice to water tanks to control the temperature during the cooling of precision alloy hot-rolled strip billets, and achieve rapid and uniform cooling of precision alloy hot-rolled strip billets after rolling.

[0005] In a first aspect, a post-rolling controlled cooling device for precision alloy hot-rolled strip is provided. This device comprises a quenching water tank, water supply pipes, a cooling box, a water pump, and a temperature and flow rate regulating unit, wherein:

[0006] The inlet of the water supply pipe is located at one end of the quenching water tank, and a cooling box and a temperature and flow rate regulating unit are sequentially arranged on the inlet side of the water supply pipe; the outlet of the water supply pipe is located at the other end of the quenching water tank, and a water pump is arranged on the outlet side of the water supply pipe.

[0007] The cooling tank is equipped with a cooling medium to cool the water entering the water supply pipe.

[0008] The temperature and flow rate regulation unit is used to obtain the current inlet water temperature and adjust the flow rate in the water delivery pipeline according to the water temperature.

[0009] Optionally, the temperature and flow rate regulating unit is specifically used to determine the water flow rate in the water supply pipeline based on the specific heat capacity of the hot-rolled strip alloy, the weight of the hot-rolled strip, the weight of the water in the water tank, the temperature difference before and after the hot-rolled strip is immersed in the water, and the time interval between the quenching of the two hot-rolled strips.

[0010] The water velocity in the water supply pipeline is determined based on the water flow rate and the cross-sectional area of ​​the pipeline.

[0011] Optionally, the water flow rate in the water supply pipeline is determined according to a first formula, which specifically includes:

[0012]

[0013] Where G is the flow rate in the water pipeline, in meters (m³). 3 / s; Δt is the time interval between the quenching of two hot-rolled strips, in seconds; C p1 C represents the specific heat capacity of the alloy, expressed in J / kg·℃. p2 ρ is the specific heat capacity of water, in J / kg·℃; m1 is the weight of the hot-rolled strip, in kg; m2 is the weight of the water in the tank, in kg; T0 is the initial water temperature, in ℃; T1 is the temperature of the hot-rolled strip before immersion in water, in ℃; T2 is the water temperature of the hot-rolled strip after quenching, in ℃; ρ is the density of water, in kg / m³. 3 .

[0014] Optionally, the water flow velocity in the water pipeline is determined according to a second formula, which specifically includes:

[0015]

[0016] Where V is the flow velocity in the water pipeline, in m / s; and G is the flow rate in the water pipeline, in m³ / s. 3 / s; S is the cross-sectional area of ​​the water pipeline, in m². 2 .

[0017] Optionally, the temperature and flow rate regulating unit is also used to determine the height of the cooling medium in the cooling box based on the water flow rate in the water supply pipe, the time interval between the quenching of the two hot-rolled strips, and the cross-sectional area of ​​the cooling medium in the cooling box.

[0018] Optionally, the cooling medium inside the cooling box can be ice.

[0019] In a second aspect, a post-rolling controlled cooling method for precision alloy hot-rolled strip is provided, applied in the post-rolling controlled cooling device of the first aspect described above, the method comprising:

[0020] S1, Before quenching the hot-rolled strip, the initial water temperature is reduced to T0 using a post-rolling controlled cooling device, and T0 ≤ 10℃.

[0021] S2, hot-rolled strip with a thickness of 3.0 to 10.0 mm, a width of 100 to 400 mm, and a temperature of T1 is immersed in water at an angle of 45° to 90°, with a total immersion time of ≤30s. After quenching, the water temperature is raised to T2. During the time interval Δt before the next hot-rolled strip is quenched, the water temperature is adjusted to below T0 by turning on the water pump, using the temperature and flow rate adjustment unit and the cooling box.

[0022] S3. After each hot-rolled strip is quenched, the water temperature must be adjusted to below T0 according to the above steps to maintain the stability of the water temperature.

[0023] Optionally, S2 specifically includes determining the water flow rate in the water supply pipeline based on the specific heat capacity of the hot-rolled strip alloy, the weight of the hot-rolled strip, the weight of the water in the water tank, the temperature difference before and after the hot-rolled strip is immersed in the water, and the time interval between the quenching of the two hot-rolled strips; and determining the water velocity in the water supply pipeline based on the water flow rate in the water supply pipeline and the cross-sectional area of ​​the water supply pipeline.

[0024] Optionally, the water flow rate in the water supply pipeline is determined according to a first formula, which specifically includes:

[0025]

[0026] Where G is the flow rate in the water pipeline, in meters (m³). 3 / s; Δt is the time interval between the quenching of two hot-rolled strips, in seconds; C p1 C represents the specific heat capacity of the alloy, expressed in J / kg·℃. p2 ρ is the specific heat capacity of water, in J / kg·℃; m1 is the weight of the hot-rolled strip, in kg; m2 is the weight of the water in the tank, in kg; T0 is the initial water temperature, in ℃; T1 is the temperature of the hot-rolled strip before immersion in water, in ℃; T2 is the water temperature of the hot-rolled strip after quenching, in ℃; ρ is the density of water, in kg / m³. 3 ;

[0027] The water flow velocity in the water pipeline is determined according to the second formula, which specifically includes:

[0028]

[0029] Where V is the flow velocity in the water pipeline, in m / s; and G is the flow rate in the water pipeline, in m³ / s. 3 / s; S is the cross-sectional area of ​​the water pipeline, in m². 2 .

[0030] Optionally, the method further includes: determining the height of the cooling medium in the cooling box based on the water flow rate in the water supply pipeline, the time interval between the quenching of the two hot-rolled strips, and the cross-sectional area of ​​the cooling medium in the cooling box.

[0031] The technical solution of this invention can achieve the following beneficial technical effects:

[0032] (1) Compared with the traditional ice-water quenching method, it is easier to operate, improves production efficiency, and reduces production costs.

[0033] (2) The precipitated strengthening phase or ordered phase transformation of the hot-rolled strip quenched by the technical solution of the present invention is fully suppressed, the solid solution structure is uniform, the hot-rolled strip has good plasticity, and can be directly subjected to continuous cold rolling. Attached Figure Description

[0034] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0035] Figure 1 A schematic diagram of a post-rolling controlled cooling device for a precision alloy hot-rolled strip provided in this application embodiment;

[0036] Figure 2 A flowchart of a post-rolling controlled cooling method for a precision alloy hot-rolled strip provided in this application embodiment;

[0037] Figure label:

[0038] 1-Quenching water tank, 2-Water supply pipe, 3-Cooling box, 4-Water pump, 5-Temperature and flow rate regulating unit. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] In the description of this invention, the terms “comprising,” “having,” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may also include other steps or units that are not expressly listed but are inherent to these processes, methods, products, or apparatuses, or steps or units added based on further optimizations of the inventive concept.

[0041] like Figure 1 The diagram shows a control and cooling device for precision alloy hot-rolled strip of the present invention. The device consists of a quenching water tank 1, a water supply pipe 2, a cooling box 3, a water pump 4, and a temperature and flow rate regulating unit 5.

[0042] Cooling tank 3 is installed at the upper part of one end of quenching water tank 1. The refrigerant in quenching water tank 1 is water, and cooling medium, such as ice blocks of varying volume, weight, and size, is placed in cooling tank 3. An automatic conveying mechanism continuously replenishes the cooling medium. Starting water pump 4 circulates the water in quenching water tank 1. After quenching the hot-rolled strip, the water temperature in quenching water tank 1 continuously rises. Starting water pump 4 and water pipe 2 delivers the heated water to cooling tank 3 at a certain flow rate or speed for heat exchange and cooling, lowering the water temperature to 0°C (the temperature of the ice-water mixture). The cooled water then flows back into quenching water tank 1, achieving the purpose of regulating and lowering the water temperature. During the water circulation process, the water temperature is monitored in real time. If the water temperature rises, it is automatically fed back to temperature and flow rate regulation unit 5, increasing the water flow rate to lower the water temperature.

[0043] In this embodiment, the cooling tank has a rectangular or circular cross-sectional area. Water is filled in the water tank as refrigerant, and ice blocks of varying volume, weight, and size are placed in the cooling bed. An automatic conveying mechanism continuously replenishes the ice blocks. Starting the water pump circulates the water in the tank. After the hot-rolled strip is quenched, the water temperature in the tank continuously rises. A water pipeline transports the heated water to the cooling bed at a certain flow rate or speed for heat exchange and cooling, lowering the water temperature to 0°C (the temperature of the ice-water mixture). The cooled water then flows back into the tank, achieving the purpose of regulating and lowering the water temperature. By measuring the water temperature in real time and automatically adjusting the water flow rate, automatic temperature regulation can be achieved, ensuring that the water temperature in the tank meets the cooling requirements and is evenly distributed.

[0044] Specifically, before quenching the hot-rolled strip, the water pump is started to circulate the water in the controlled cooling device, which includes the post-rolling controlled cooling device to lower the initial water temperature to T0, ensuring that T0 ≤ 10℃. A hot-rolled strip with a thickness of 3.0–10.0 mm, a width of 100–400 mm, and a temperature of T1 is immersed in the water at an angle of 45°–90°, with a total immersion time ≤ 30 seconds. After quenching, the water temperature rises to T2. During the time interval Δt before quenching the next hot-rolled strip, the water pump is turned on, and the temperature and flow rate regulating unit and cooling tank are used to adjust the water temperature below T0.

[0045] The temperature and flow rate regulating unit is specifically used to determine the water flow rate in the water supply pipeline based on the specific heat capacity of the hot-rolled strip alloy, the weight of the hot-rolled strip, the weight of the water in the water tank, the temperature difference before and after the hot-rolled strip enters the water, and the time interval between the quenching of two hot-rolled strips; and to determine the water velocity in the water supply pipeline based on the water flow rate and the cross-sectional area of ​​the water supply pipeline. Specifically:

[0046] The water flow rate in the water pipeline is determined according to the first formula, which specifically includes:

[0047]

[0048] Where G is the flow rate in the water pipeline, in meters (m³). 3 / s; Δt is the time interval between the quenching of two hot-rolled strips, in seconds; C p1 C represents the specific heat capacity of the alloy, expressed in J / kg·℃. p2 ρ is the specific heat capacity of water, in J / kg·℃; m1 is the weight of the hot-rolled strip, in kg; m2 is the weight of the water in the tank, in kg; T0 is the initial water temperature, in ℃; T1 is the temperature of the hot-rolled strip before immersion in water, in ℃; T2 is the water temperature of the hot-rolled strip after quenching, in ℃; ρ is the density of water, in kg / m³. 3 .

[0049] Further evidence:

[0050]

[0051] Determining the water flow velocity in the water pipeline can be simplified to the second formula, which specifically includes:

[0052]

[0053] Where V is the flow velocity in the water pipeline, in m / s; and G is the flow rate in the water pipeline, in m³ / s. 3 / s; S is the cross-sectional area of ​​the water pipeline, in m². 2 .

[0054] To ensure that the water in the water pipeline has sufficient heat exchange area to drop to 0℃ after passing through the cooling bed, the ice layer height h in the cooling bed should be ≥ GΔt / A (where A is the cross-sectional area of ​​the cooling bed).

[0055] After each hot-rolled strip is quenched, the water temperature T2 is measured in real time. If it is higher than T0, the temperature control sensor will automatically feed back to the temperature flow regulation unit to increase the water flow and adjust the water temperature to below T0 in order to maintain the stability of the water temperature.

[0056] The following provides an optional embodiment of the present invention. The present invention combines the controlled cooling of hot-rolled strip billets of 1J22 soft magnetic alloy and 3J1 elastic alloy after rolling, and the comparative example of using conventional ice-water cooling to quench 1J22 and 3J1 hot-rolled strip billets, to illustrate a method for controlled cooling of precision alloy hot-rolled strip billets after rolling. A method for controlled cooling of precision alloy hot-rolled strip billets after rolling, as follows... Figure 2 The method includes the following steps:

[0057] S1, before the hot-rolled strip is quenched, the initial water temperature is reduced to T0 using a post-rolling controlled cooling device, and T0 ≤ 10℃.

[0058] S2, a hot-rolled strip with a thickness of 3.0-10.0 mm, a width of 100-400 mm, and a temperature of T1 is immersed in water at an angle of 45°-90°, with a total immersion time of ≤30s. After quenching, the water temperature rises to T2. During the time interval Δt before the next hot-rolled strip is quenched, the water temperature is adjusted to below T0 using a controlled cooling device. In this step, the flow rate G of the water requiring heat exchange and cooling in the water pipeline is calculated using equation (1), and the water velocity is calculated using equation (2).

[0059] S3. After each hot-rolled strip is quenched, the water temperature must be lowered to below T0 to maintain the stability of the water temperature.

[0060] The post-rolling cooling process parameters for the hot-rolled strip in the embodiments and comparative examples are shown in Table 1. Other physical parameters used in the calculations are: 1J22, 3J1, and the specific heat capacity of water are 459 J / kg·℃, 422 J / kg·℃, and 4200 J / kg·℃, respectively; the density of the cooling water is 103 kg / m³. 3 The weight is 12 tons, the quenching time interval between every two hot-rolled strips is 5 minutes, and the cross-sectional area of ​​the water pipeline is 0.7536 m². 2 (100mm in diameter).

[0061] Table 1. Post-rolling cooling process parameters for hot-rolled strip in the examples and comparative examples.

[0062]

[0063] The mechanical properties of the hot-rolled strips in the embodiments and comparative examples at different transverse locations are shown in Tables 2 and 3. Tensile specimens were taken from the middle section of the hot-rolled strips during the later stages of hot rolling and quenching. As can be seen from the data in the tables, the 1J22 and 3J1 hot-rolled strips quenched using the embodiments of the present invention exhibit uniform and stable mechanical properties, high elongation, and good plasticity. In contrast, the 1J22 and 3J1 hot-rolled strips in the comparative examples, due to incomplete suppression of phase transformation, exhibit poor uniformity in strength and plasticity. The 1J22 strip is brittle and difficult to continue cold working, while the 3J1 strip has high local strength and low plasticity, making subsequent cold rolling difficult.

[0064] Table 2 Mechanical properties of J22 hot-rolled strip (transverse direction) in Examples and Comparative Example 1

[0065]

[0066] Table 3 Mechanical properties of hot-rolled strip (transverse direction) of Example 3J1 and Comparative Example 3J1

[0067]

[0068] In summary, the advantages of this invention are that the amount of ice used for cooling is controllable, the temperature constantness of the ice-water mixture is fully utilized, and the water temperature is controlled in real time by controlling the flow rate and velocity of the circulating water, thereby achieving automatic water temperature regulation. This ensures that the water temperature in different parts of the water tank is uniform and stable, resulting in more uniform quenching and better quenching effect for the hot-rolled strip.

[0069] The post-rolling controlled cooling method for precision alloy hot-rolled strip provided in this application embodiment is implemented in the aforementioned post-rolling controlled cooling device for precision alloy hot-rolled strip. Specific limitations regarding the post-rolling controlled cooling method for precision alloy hot-rolled strip can be found in the above-described limitations regarding the post-rolling controlled cooling device for precision alloy hot-rolled strip, and will not be repeated here. Each component of the aforementioned post-rolling controlled cooling device for precision alloy hot-rolled strip can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in hardware form, or stored in the memory of the device in software form, so that the processor can call and execute the operations corresponding to each module.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A controlled cooling device for post-rolling of precision alloy hot-rolled strip, characterized in that, The device consists of a quenching water tank, water supply pipelines, a cooling box, a water pump, and a temperature and flow rate regulating unit, wherein: The inlet of the water supply pipe is located at one end of the quenching water tank, and a cooling box and a temperature and flow rate regulating unit are sequentially arranged on the inlet side of the water supply pipe; the outlet of the water supply pipe is located at the other end of the quenching water tank, and a water pump is arranged on the outlet side of the water supply pipe. The cooling tank is equipped with a cooling medium to cool the water entering the water supply pipe. The temperature and flow rate regulation unit is used to obtain the current inlet water temperature and adjust the flow rate in the water delivery pipeline according to the water temperature. The temperature and flow rate regulating unit is specifically used to determine the water flow rate in the water supply pipeline based on the specific heat capacity of the hot-rolled strip alloy, the weight of the hot-rolled strip, the weight of the water in the water tank, the temperature difference before and after the hot-rolled strip enters the water, and the time interval between the quenching of the two hot-rolled strips. The water velocity in the water supply pipeline is determined based on the water flow rate and the cross-sectional area of ​​the pipeline. The water flow rate in the water pipeline is determined according to a first formula, which specifically includes: ， Where G is the flow rate in the water pipeline, in meters (m³). 3 / s; Δt is the time interval between the quenching of two hot-rolled strips, in seconds; C p1 C represents the specific heat capacity of the alloy, expressed in J / kg·℃. p2 ρ is the specific heat capacity of water, in J / kg·℃; m1 is the weight of the hot-rolled strip, in kg; m2 is the weight of the water in the tank, in kg; T0 is the initial water temperature, in ℃; T1 is the temperature of the hot-rolled strip before it enters the water, in ℃; ρ is the density of water, in kg / m³. 3 ; The water flow velocity in the water pipeline is determined according to the second formula, which specifically includes: ， Where V is the flow velocity in the water pipeline, in m / s; and G is the flow rate in the water pipeline, in m³ / s. 3 / s; S is the cross-sectional area of ​​the water pipeline, in m². 2 .

2. The apparatus according to claim 1, characterized in that, The temperature and flow rate regulating unit is also used to determine the height of the cooling medium in the cooling box based on the water flow rate in the water supply pipeline, the time interval between the quenching of the two hot-rolled strips, and the cross-sectional area of ​​the cooling medium in the cooling box.

3. The apparatus according to claim 1, characterized in that, The cooling box contains ice as the cooling medium.

4. A method for controlled cooling after rolling of precision alloy hot-rolled strip, applied in the controlled cooling device as described in any one of claims 1-3, characterized in that, The method includes: S1, Before quenching the hot-rolled strip, the initial water temperature is reduced to T0 using a post-rolling controlled cooling device, and T0 ≤ 10℃. S2, hot-rolled strip with a thickness of 3.0~10.0mm, a width of 100~400mm, and a temperature of T1 is immersed in water at an immersion angle of 45°~90°, with a total immersion time of ≤30s. After quenching, the water temperature is raised to T2. During the time interval Δt before the next hot-rolled strip is quenched, the water temperature is adjusted to below T0 by turning on the water pump, using the temperature and flow rate adjustment unit and the cooling box. S3. After each hot-rolled strip is quenched, the water temperature must be adjusted to below T0 according to the above steps to maintain the stability of the water temperature. S2 specifically includes determining the water flow rate in the water supply pipeline based on the specific heat capacity of the hot-rolled strip alloy, the weight of the hot-rolled strip, the weight of the water in the water tank, the temperature difference before and after the hot-rolled strip is immersed in the water, and the time interval between the quenching of the two hot-rolled strips; and determining the water velocity in the water supply pipeline based on the water flow rate in the water supply pipeline and the cross-sectional area of ​​the water supply pipeline. The water flow rate in the water pipeline is determined according to a first formula, which specifically includes: ， Where G is the flow rate in the water pipeline, in meters (m³). 3 / s; Δt is the time interval between the quenching of two hot-rolled strips, in seconds; C p1 C represents the specific heat capacity of the alloy, expressed in J / kg·℃. p2 ρ is the specific heat capacity of water, in J / kg·℃; m1 is the weight of the hot-rolled strip, in kg; m2 is the weight of the water in the tank, in kg; T0 is the initial water temperature, in ℃; T1 is the temperature of the hot-rolled strip before it enters the water, in ℃; ρ is the density of water, in kg / m³. 3 ; The water flow velocity in the water pipeline is determined according to the second formula, which specifically includes: ， Where V is the flow velocity in the water pipeline, in m / s; and G is the flow rate in the water pipeline, in m³ / s. 3 / s; S is the cross-sectional area of ​​the water pipeline, in m². 2 .

5. The method according to claim 4, characterized in that, The method further includes: The height of the cooling medium in the cooling box is determined based on the water flow rate in the water pipeline, the time interval between the quenching of the two hot-rolled strips, and the cross-sectional area of ​​the cooling medium in the cooling box.

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