A method for preventing black and gray defects in thick wheel steel plates and the steel plate

Abstract

This application provides a method and a steel plate for preventing black and gray defects on thick-gauge wheel steel plates. The method includes: controlling the temperature of the steel plate entering the finishing mill at an amount less than or equal to 970°C; controlling the amount of water sprayed by the cooling water spray device between the finishing mill stands to be greater than or equal to 10% of the maximum spray volume of the cooling water spray device; and employing small convexity control to ensure that the target convexity of the steel plate is less than or equal to 50 μm. This application solves the problem of black and gray defects on the surface of thick-gauge wheel steel plates, improving the quality of thick-gauge wheel steel plates and the market competitiveness of products made from them.

Description

Technical Field

[0001] This application relates to the field of steel rolling technology, and in particular to a method and a steel plate for preventing black and gray defects in thick wheel steel plates. Background Technology

[0002] The wheel is one of the most important components for vehicle safety. It bears the vehicle's vertical load, lateral force, driving and braking torque, and various stresses generated during driving. Because it is a rotating body, it requires high-precision dimensions, minimal imbalance, and correct rim shape (profile, size, and form) to support the tire. It also needs a certain degree of rigidity and elasticity, fatigue resistance, light weight, and good fuel economy. To increase wheel rigidity and improve safety margins, some wheel manufacturers are gradually increasing the strength and thickness of materials.

[0003] In the existing solution, after the thick-gauge wheel steel plates are produced, when they reach the customer for processing into wheels, it is found that a large amount of black ash appears on the surface of the steel plates. The black ash defects are present in the same width direction of the steel plates, especially at the edges of the steel plates, where the incidence of black ash defects is as high as 30%. This not only affects the quality of the finished wheels, but also pollutes the processing environment for wheel processing, seriously affecting the market acceptance of thick-gauge wheel steel products.

[0004] Therefore, how to solve the problem of black and gray defects on the surface of thick wheel steel plates and improve the quality of thick wheel steel plates is an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method, device, medium and equipment for preventing strip breakage in a leveling machine. This application solves the problem of black and gray defects on the surface of thick wheel steel plates, improves the quality of thick wheel steel plates and the market competitiveness of products made from thick wheel steel plates.

[0006] Specifically, this application adopts the following technical solution:

[0007] According to a first aspect of the present application, a method is provided to prevent the generation of black and gray defects in thick-gauge wheel steel plates. The method includes: controlling the temperature of the steel plate when it enters the inlet of the finishing mill to be less than or equal to 970°C; controlling the amount of water sprayed by the cooling water spray device between the stands of the finishing mill to be greater than or equal to 10% of the maximum value of the cooling water spray device; and using small convexity control to make the target convexity of the steel plate less than or equal to 50μm.

[0008] In some embodiments of this application, based on the aforementioned scheme, controlling the temperature of the steel plate entering the finishing mill entrance to be less than or equal to 970°C includes: cooling the steel plate by spraying cooling water during the roughing process and controlling the time when the steel plate arrives at the finishing mill entrance, so that the temperature of the steel plate entering the finishing mill entrance is controlled to be less than or equal to 970°C.

[0009] In some embodiments of this application, based on the foregoing scheme, the adoption of small crown control to make the target crown of the steel plate less than or equal to 50 μm includes: the steel plate adopts small crown control in the finishing rolling process, and the target crown of the steel plate is made less than or equal to 50 μm by adjusting the rolling force of the finishing rolling mill and the roll gap of the finishing rolling mill rolls.

[0010] In some embodiments of this application, based on the foregoing scheme, the thickness of the steel plate is greater than or equal to 13 mm.

[0011] In some embodiments of this application, based on the foregoing scheme, the number of finishing mill stands is 7.

[0012] In some embodiments of this application, based on the foregoing scheme, the number of cooling water spray devices between the finishing mill stands is 6.

[0013] In some embodiments of this application, based on the aforementioned scheme, the steel plate is used for the manufacture of heavy-duty truck wheels.

[0014] In some embodiments of this application, based on the aforementioned scheme, the steel plate production process sequentially involves heating in a heating furnace, rough rolling, finish rolling, and coiling.

[0015] In some embodiments of this application, based on the foregoing scheme, the amount of water sprayed by the cooling water spraying device is controlled by the nozzle opening of the cooling water spraying device.

[0016] According to a second aspect of the embodiments of this application, a thick-gauge wheel steel plate is provided, which is prepared by the method described above for preventing the generation of black and gray defects in the thick-gauge wheel steel plate.

[0017] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0018] The solution proposed in this application can solve the problem of black and gray defects on the surface of thick wheel steel plates, thereby improving the quality of thick wheel steel plates and thick wheel steel products. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating a method for preventing black and gray defects in thick wheel steel plates according to one embodiment of this application is shown. Detailed Implementation

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0022] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0023] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0025] The implementation details of the technical solutions in the embodiments of this application are described in detail below:

[0026] Reference Figure 1 , Figure 1 This is a flowchart illustrating a method for preventing black and gray defects in thick wheel steel plates according to one embodiment of this application.

[0027] According to a typical embodiment of this application, a method for preventing black and gray defects in thick-gauge wheel steel plates is provided, the method comprising the following steps S1 to S3:

[0028] Step S1: Control the temperature of the steel plate when it enters the finishing mill to be less than or equal to 970℃.

[0029] Step S2: Control the amount of water sprayed by the cooling water spray device between the stands of the finishing mill to be greater than or equal to 10% of the maximum amount of water sprayed by the cooling water spray device.

[0030] Step S3: Use small convexity control to make the target convexity of the steel plate less than or equal to 50μm.

[0031] In this application, to ensure the overall rigidity of heavy truck wheels, there is a trend towards gradually increasing thickness of the spoke steel. However, when the thick-gauge wheel steel plates reach the customer for processing, a large amount of black ash appears on the surface of the steel plates. Black ash defects exist in the same width direction of the steel plates, with the edges being more severely affected. The incidence of black ash defects is as high as 30%, which not only affects the quality of the finished wheel steel plates but also pollutes the processing environment during processing, causing inconvenience to processing workers. Energy dispersive spectroscopy (EDS) analysis of the black ash on the steel plates revealed that it is pure iron oxide. Based on Evans' theory on the cracking and peeling of metal oxide films, it can be known that for a specific steel grade, the influencing factors are the straightening process (which cannot be modified on-site), initial crack size, oxide film thickness, and the elastic modulus of the matrix and iron oxide scale. Among these, the controllable points are the size and structure of the iron oxide scale. The factors affecting the size of the iron oxide scale include: temperature affecting the growth rate; and time affecting the amount formed. Temperature affects the structure of the iron oxide scale during the growth and co-deposition process. Based on the above analysis, it was found that by controlling the temperature of the steel plate entering the finishing mill to be less than or equal to 970℃, controlling the amount of water sprayed by the cooling water spray device between the finishing mill stands to be greater than or equal to 10% of the maximum spray volume of the cooling water spray device, and using small crown control to make the target crown of the steel plate less than or equal to 50μm, the occurrence of black and gray defects in thick-gauge wheel steel plates can be reduced, thereby improving the quality of thick-gauge wheel steel plates and the market competitiveness of products made from thick-gauge wheel steel plates.

[0032] In one embodiment of this application, controlling the temperature of the steel plate entering the finishing mill at an inlet of less than or equal to 970°C includes:

[0033] By spraying cooling water to cool the steel plate during the roughing process and controlling the time when the steel plate reaches the entrance of the finishing mill, the temperature of the steel plate entering the finishing mill is controlled to be less than or equal to 970°C.

[0034] In this application, the temperature of the steel plate entering the finishing mill inlet is less than or equal to 970°C. To ensure that the temperature of the steel plate entering the finishing mill inlet is less than or equal to 970°C, it is necessary to cool the steel plate by spraying cooling water during the roughing rolling process. This is because the steel plate is continuously heated in the heating furnace, and its temperature is higher than 970°C when it exits the heating furnace. Spraying cooling water onto the steel plate during rolling in the roughing mill stand cools the strip, ensuring that the strip... The temperature of the steel plate upon reaching the entrance of the finishing mill is less than or equal to 970°C. The time it takes for the steel plate to reach the entrance of the finishing mill can also be controlled. If the temperature of the steel plate is still higher than 970°C before reaching the entrance, the time it takes for the steel plate to reach the entrance allows for heat dissipation, ensuring that the temperature of the steel plate upon entering the finishing mill is less than or equal to 970°C. This reduces the thickness of the iron oxide scale, improves its structure, and reduces the amount of iron oxide scale on the surface of the steel plate, preventing black ash defects.

[0035] In one embodiment of this application, the use of small convexity control, such that the target convexity of the steel plate is less than or equal to 50 μm, includes:

[0036] The steel plate is controlled with small crown in the finishing rolling process. By adjusting the rolling force of the finishing mill and the roll gap of the finishing mill rolls, the target crown of the steel plate is less than or equal to 50μm.

[0037] In this application, the small convexity control is adopted to ensure that the target convexity of the steel plate is less than or equal to 50 μm. To ensure that the target convexity of the steel plate is less than or equal to 50 μm, small convexity control needs to be adopted in the finishing rolling process. (To the naked eye, a steel plate appears as a rectangular block, but to be precise, the rolled steel plate is a block with a high center and low sides. During rolling, the steel plate needs to be rolled into a rectangular block as much as possible. This makes it less likely for air to enter from the edges when the steel plate is coiled, thus ensuring the quality of the steel plate and preventing large-area oxidation of the steel plate edges, which would lead to large-area black and gray defects.) The target convexity of the steel plate is less than or equal to 50 μm by adjusting the rolling force of the finishing mill and the roll gap size of the finishing mill rolls. This reduces the distance between the layers at the edges, reduces the amount of air entering the steel plate edges, improves the quality of the steel plate edges, and prevents large-area oxidation of the edges, which would lead to black and gray defects.

[0038] In one embodiment of this application, the thickness of the steel plate may be greater than or equal to 13 mm.

[0039] In this application, the thickness of the steel plate can be 13mm, 14mm or other specifications of wheel steel plate. After the customer processes the steel plate into finished wheel products, the finished product has the same thickness as the steel plate. When the customer processes the steel plate, the thickness of the steel plate is not changed, so as to ensure the rigidity of the finished product after the steel plate is processed.

[0040] In one embodiment of this application, the number of finishing mill stands can be 7.

[0041] In one embodiment of this application, the number of cooling water spray devices between the finishing mill stands can be 6 stands.

[0042] In this application, the number of finishing mill stands can be 7 or 8, etc., and the number of cooling water spray devices between the finishing mill stands can be 6 or 7, etc. This application does not impose any special restrictions on the number of cooling water spray devices between the finishing mill stands. In actual production, the number can be adjusted according to actual needs. This application does not impose any special restrictions.

[0043] In this application, the cooling water spray device is used to cool the steel plate during rolling. This reduces the surface temperature of the steel plate during rolling, thereby slowing down the growth rate of iron oxide scale and reducing the generation of black and gray defects on the surface of the steel plate. The cooling water spray device also reduces the surface temperature of the rolls, reducing the thermal impact of the strip on the roll surface and reducing the generation of cracks. This protects the safety of the rolling mill equipment and ensures the quality of the strip.

[0044] In one embodiment of this application, the steel plate can be used to manufacture heavy truck wheels.

[0045] In this application, the steel plates are mostly used for the manufacture of heavy-duty truck wheels, because heavy-duty trucks have higher requirements for the overall rigidity of the wheels, and thick wheel steel plates with a thickness of 13mm or more can meet the requirements of heavy-duty trucks for the high overall rigidity of the wheels.

[0046] In one embodiment of this application, the steel plate is produced by sequentially heating in a heating furnace, rough rolling, finish rolling, and coiling.

[0047] In this application, the steel plate production process sequentially involves heating in a heating furnace, rough rolling, finish rolling, and coiling. After heating, finish rolling, and rough rolling, the steel plate is coiled into rolls and placed for sale to customers. In particular, during the coiling process, if the target convexity of the steel plate is not controlled to be less than or equal to 50μm during the finish rolling process, the distance between the layers at the edge of the coiled steel plate will be too large, making it easy for air to enter and resulting in a large number of black and gray defects on the edge of the steel plate. Therefore, controlling the target convexity of the steel plate to be less than or equal to 50μm during the finish rolling process can greatly improve the quality of the steel plate edge and ultimately improve the market competitiveness of the products made from the steel plate.

[0048] In one embodiment of this application, the amount of water sprayed by the cooling water spraying device is controlled by the nozzle opening of the cooling water spraying device.

[0049] In this application, the amount of water sprayed by the cooling water spraying device is controlled by the nozzle opening of the cooling water spraying device. When the amount of water to be sprayed increases, the nozzle opening of the cooling water spraying device is increased, and the amount of water sprayed increases. When the amount of water to be sprayed decreases, the nozzle opening of the cooling water spraying device is decreased, and the amount of water sprayed decreases. The nozzle opening of the cooling water spraying device can be adjusted according to actual production.

[0050] According to a typical embodiment of this application, this application also proposes a thick-gauge wheel steel plate, which is prepared by the method described above for preventing black and gray defects in thick-gauge wheel steel plates.

[0051] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0052] Firstly, the proposed solution can solve the problem of black and gray defects on the surface of thick wheel steel plates, thereby improving the quality of thick wheel steel plates.

[0053] Secondly, by adopting the solution proposed in this application, excessive air can be prevented from entering the edge after the steel plate is rolled and then coiled, which would lead to serious black and gray defects on the edge of the steel plate, thus greatly improving the quality of products made from thick-gauge wheel steel plates.

[0054] Third, adopting the solution proposed in this application can enhance the market competitiveness of thick-gauge wheel steel products, win customers' trust in thick-gauge wheel steel plate manufacturers, and greatly increase the company's revenue.

[0055] Although this application has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since this application can be embodied in many forms without departing from the spirit or substance of the application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A method for preventing black and gray defects in thick-gauge wheel steel plates, characterized in that, The steel plate has a thickness of 13 mm or more, and the method includes: Controlling the temperature of the steel plate entering the finishing mill entrance to be less than or equal to 970°C includes: cooling the steel plate by spraying cooling water during the roughing process and controlling the time when the steel plate arrives at the finishing mill entrance, so that the temperature of the steel plate entering the finishing mill entrance is controlled to be less than or equal to 970°C; wherein, the number of finishing mill stands is 7; The amount of water sprayed by the cooling water spraying device between the stands of the finishing mill is greater than or equal to 10% of the maximum amount of water sprayed by the cooling water spraying device; wherein, the number of cooling water spraying devices between the stands of the finishing mill is 6. The method of using small crown control to make the target crown of the steel plate less than or equal to 50 μm includes: the steel plate is subjected to small crown control in the finishing rolling process by adjusting the rolling force of the finishing mill and the roll gap of the finishing mill rolls to make the target crown of the steel plate less than or equal to 50 μm.

2. The method according to claim 1, characterized in that, The steel plate is used to manufacture heavy-duty truck wheels.

3. The method according to claim 1, characterized in that, The steel plate is produced by heating in a furnace, rough rolling, finish rolling, and coiling in sequence.

4. The method according to claim 1, characterized in that, The amount of water sprayed by the cooling water spraying device is controlled by the nozzle opening of the cooling water spraying device.

5. A thick-gauge wheel steel plate, characterized in that, The thick-gauge wheel steel plate is prepared by the method described in any one of claims 1-4 to prevent black and gray defects in the thick-gauge wheel steel plate.

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