Quantitative evaluation method for oxidation film of hot continuous rolling high-speed steel roller

Abstract

The invention provides a quantitative evaluation method for an oxidation film of a hot continuous rolling high-speed steel roller, which comprises the following steps of: 1, maintaining the oxidation film state of the surface of the roller during working after rolling is stopped, and preventing subsequent oxidation of the roller; 2, reducing the influence of the measurement process; step 3, carrying out data acquisition; step 3.1, determining a data acquisition position on the surface of the roller; step 3.2, color data acquisition is carried out; step 3.3, carrying out roughness data acquisition; and step 4, evaluating the state of the oxidation film on the surface of the roller based on the color data and the roughness data acquired in the step 3. According to the evaluation method, the color parameters and the roughness are comprehensively quantified, the evaluation result is more scientific and higher in guidance, and the evaluation result is less affected by people and the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to a quantitative evaluation method for oxide films of hot-rolled high-speed steel rolls. Background Art

[0002] High-speed steel rolls are complex alloy steels containing carbide-forming elements such as tungsten, molybdenum, chromium, and vanadium, with the total alloying element content reaching approximately 10% to 25%. Compared to traditional high-chromium iron rolls, high-speed steel rolls offer higher hardness, better wear resistance, and enhanced hardenability. Furthermore, their use significantly extends roll life and improves product surface quality and shape. Consequently, many established hot rolling production lines have gradually adopted high-speed steel rolls.

[0003] Although high-speed steel work rolls have the characteristics of low wear and good wear resistance, the types and specifications of each rolling are different, and the rolling loads of each type and specification of strip on each stand are different, resulting in different roll surface conditions each time the work rolls are unloaded. However, when producing different strip products, there are obvious differences in the requirements for roll surface conditions due to differences in surface quality requirements and rolling stability. Generally, manufacturers will establish their own roll surface evaluation standards based on experience to facilitate the determination of the applicable rolling plan of the rolls and facilitate grinding arrangements. At present, most companies manually observe the roll surface according to the morphology of the roll surface and the peeling of the oxide film, and then refer to the standard roll surface grade standard to make the corresponding grade judgment, and record the roll surface grade of the corresponding roll number in the work roll management system. Tangshan Iron and Steel [A Brief Discussion on the Application Technology of High-Speed ​​Steel Rolls in Hot-Strip Production Lines [J]. China Metal Bulletin, 2022(15):113-116.] published a roll oxide film rating method based on manual observation. This method is based entirely on manual experience and judgment, and the evaluation accuracy is significantly affected by human factors. Chinese patent document CN104923576B discloses an automatic detection device for the surface of finishing work rolls in hot-strip production lines. This is an automatic rating device developed based on manual rating. This automatic work roll surface inspection device includes two work roll surface imaging systems and a work roll surface grading system. The work roll surface imaging systems are located on both sides of the roll-changing trolley track. Each work roll surface imaging system includes a detection mechanism and a imaging mechanism. The work roll surface grading system includes an image management system and a grading system. The image management system processes the roll surface images transmitted by the roll surface imaging systems, characterizes and digitizes the roll surface image features through an image management program, and transmits the roll surface information data to the grading system. The grading system is pre-set with roll surface standard maps and roll surface grades. The image processing system compares the off-roll roll surface images processed by the image processing system with the work roll surface standards for training and learning, automatically assigning the roll surface grade to be graded, and transmitting the determined grade information to the work roll management system for recording. This method requires a large number of sample statistics to achieve relatively accurate comparative grading. Furthermore, conventional camera-based images are significantly affected by lighting and environmental factors, resulting in low evaluation accuracy. Chinese patent publication number CN112122366A discloses an online inspection system for hot-roller surfaces. Its core is image recognition-based roll surface condition assessment, enabling timely and effective detection of deterioration trends in the oxide film on the roll surface. This online inspection method is significantly affected by environmental factors such as water vapor, light, and temperature. Furthermore, the diverse variations in roll surface color and defect shape make identification challenging. Chinese patent publication number CN118937572A discloses a method for dynamic analysis and evaluation of high-temperature oxide films on rolls. This method utilizes experimental analysis, conducting constant-temperature oxidation and thermal corrosion tests on the rolls. The oxidation index and thermal corrosion index are then used to dynamically analyze and evaluate the roll oxide film.This method is a destructive experiment with a long detection cycle and cannot be applied on site.

[0004] In summary, existing roll oxide film evaluation methods mostly rely on manual experience-based ratings. Due to individual differences in skill level, observation angle, on-site environment, and evaluation preferences, rating results are significantly influenced by subjective factors. Roller surface rating methods based on deep learning and image recognition, however, can only partially address the individual differences and subjective influences of manual ratings due to issues with the image capture environment and processing methods. Ultimately, they are still based entirely on empirical criteria and lack a quantitative basis. Summary of the Invention

[0005] To address the aforementioned technical issues, a method for quantitatively evaluating oxide films on hot-rolled high-speed steel rolls is provided. This method utilizes quantitative roller surface color parameters and roughness values ​​as quantitative evaluation criteria for oxide films, further enhancing the scientific nature of roll surface evaluation and the guiding significance of roll surface rating, based on the fact that roll surface oxide films exhibit different colors depending on their thickness and composition, and that roughness changes with the formation and flaking of the roll surface oxide film. This method further improves the scientific nature of roll surface evaluation and enhances the guiding significance of roll surface rating.

[0006] The technical means adopted in the present invention are as follows:

[0007] A quantitative evaluation method for oxide film of hot-rolled high-speed steel rolls comprises the following steps:

[0008] Step 1: After stopping rolling, the oxide film state of the roller surface is maintained in the working state to prevent the roller from subsequent oxidation;

[0009] Step 2: Reduce the impact of the measurement process;

[0010] Step 3: collect data;

[0011] Step 3.1, determining the data collection position on the roller surface;

[0012] Step 3.2, collect color data;

[0013] Step 3.3, collect roughness data;

[0014] Step 4: Based on the color data and roughness data collected in step 3, the state of the oxide film on the roller surface is evaluated.

[0015] Furthermore, in step 1, after stopping rolling, the roller surface is sprayed with water for cooling for more than 5 minutes to reduce the roller surface temperature to below the re-oxidation temperature.

[0016] Furthermore, the roller surface temperature is lowered to below 100°C after water cooling.

[0017] Furthermore, the cooling depth is above 50 mm to prevent the roller surface temperature from being too high due to the temperature transfer from the roller core.

[0018] Furthermore, in step 2, the roller surface temperature is controlled at 30-50° C. during measurement; and before measurement, a cleaning agent is used to clean the rust and oil stains at the measurement position.

[0019] Furthermore, in step 2, the roller surface temperature is controlled at 40° C. during measurement.

[0020] Furthermore, in step 3.1, determining the data collection position on the roller surface includes: taking the maximum rolling width in the roller body direction as the data collection area, removing 30 mm on both sides, and evenly distributing 5 measurement positions for data collection.

[0021] Furthermore, in step 3.2, the color data collection includes: using Lab color space as the measurement standard, collecting the L * 、a * 、b * Data and record, where L * The parameters are light and dark features, a * The parameters are red and green features, b * The parameters are yellow-blue features.

[0022] Furthermore, in step 3.3, the roughness data collection includes: using a roughness meter with a resolution higher than 0.01um to collect and record the roughness data of each measuring position on the roller surface, and using the surface roughness Ra parameter as a characterization to comprehensively characterize the growth and peeling characteristics of the oxide film on the roller surface.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention provides a quantitative evaluation method for the oxide film of hot-rolled high-speed steel rollers. The evaluation method of the present invention uses color parameters and roughness to comprehensively quantify the composition, thickness and wear of the most important factors in evaluating the status of the roller oxide film. The evaluation results are more scientific and more instructive, and are less affected by humans and the environment.

[0025] Based on the above reasons, the present invention can be widely promoted in fields such as roll surface evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 Flowchart of the method of the present invention. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0032] Example 1

[0033] The technical problem addressed by the present invention is that the state of the roller oxide film is a key factor affecting rolling process stability and product surface quality. Existing methods for evaluating the state of the roller oxide film are based on empirical judgment, which is significantly influenced by accumulated experience and environmental factors. This method cannot accurately determine the state of the roller oxide film, thereby exacerbating fluctuations in production process stability and product quality.

[0034] The composition and thickness of the roller oxide film are two of the most important indicators determining the quality and stability of the roller surface. These two indicators cannot be measured on-site. However, research has found that changes in the composition and thickness of the roller oxide film can cause the roller surface to exhibit different colors. Furthermore, as the roller oxide film forms and peels off, the roller surface roughness also changes. This invention uses quantitative roller surface color parameters and roughness values ​​as quantitative evaluation criteria for roller oxide film, further improving the scientific nature of roller surface evaluation and enhancing the guiding significance of roller surface rating.

[0035] The present invention provides a quantitative evaluation method for the oxide film of a hot-rolled high-speed steel roll, which is a quantitative evaluation method for the oxide film state of the roll that can be applied on-site in production, and comprises the following steps:

[0036] The first step is to maintain the oxide film state on the roller surface during operation to prevent subsequent oxidation of the roller;

[0037] Specifically, the process includes: continuing to spray water on the roller surface for more than 5 minutes after stopping rolling (during the water spraying process, the roller rotates at a uniform speed and the circumferential surface needs to be cooled) to reduce the roller surface temperature to below the re-oxidation temperature (generally controlled below 100°C); the cooling depth is more than 50mm (the cooling depth here refers to the range of cooling achieved by the cooling water, specifically the cooling range on the radius, that is, the distance from the deepest point of cooling to the surface) to prevent the roller surface temperature from being too high due to the transfer of roller core temperature; this step uses water spray cooling and controls the cooling depth to prevent re-oxidation. If the cooling depth is not enough, the roller surface will return to red, causing the roller surface temperature to exceed 100°C;

[0038] Step 2: Reduce the impact of the measurement process;

[0039] Specifically, during measurement, the roll surface temperature is controlled between 30°C and 50°C, preferably 40°C, to ensure both instrument accuracy and minimize the time it takes for the rolls to cool down. Before measurement, use a cleaning agent to clean any loose rust and oil stains at the measurement location. In this step, the roll surface temperature is controlled between 30°C and 50°C through natural air cooling, primarily to meet measurement and time requirements. The required surface temperature is sufficient.

[0040] Step 3: Data collection;

[0041] Specifically, it includes: (1) Data collection positions on the roll surface: in the roll body direction, the maximum rolling width is used as the data collection area (the maximum rolling width is the maximum width of the rolled steel plate during the roll cycle, and the confirmed usage range), 30mm is removed on both sides (removing 30mm on both sides means subtracting 30mm on both sides from the maximum width. For example, if the maximum width is 1760mm, the measurement range is 1700mm), and 5 to 8 measurement positions are evenly distributed for data collection; the number of measurement positions can be more than 5, preferably 5. Based on the time taken for measurement, 5 measurement positions can obtain complete roll surface status information; for the 5 measurement positions, even distribution means that the measurement area determined above is evenly divided into 4 parts with the axial center of the roll as a reference, and 5 measurement positions are determined. The 5 measurement positions only need to consider the axial position, and do not need to consider the circumferential position (do not need to be on a straight line). Since the circumferential difference is very small, there is no oxidation in the radial direction, and it cannot be measured, it is not considered.

[0042] (2) Color data collection at the measurement position: Using Lab color space as the measurement standard, collect the L * 、a * 、b * Data and records;

[0043] (3) Roughness data collection at the measuring position: Use a roughness meter with a resolution higher than 0.01 μm to collect the roughness data at each measuring position on the roller surface, use the Ra parameter as a characterization, and record it;

[0044] In step 4, the data collected in step 3 are used to evaluate the status of the oxide film on the roll surface.

[0045] The present invention utilizes roller surface color variations based on the thickness and composition of the roller oxide film. Furthermore, the roughness of the roller surface changes with the formation and flaking of the oxide film. By using quantitative roller surface color parameters and roughness values ​​as quantitative evaluation criteria for roller oxide films, the method further enhances the scientific nature of roller surface evaluation and provides greater guidance for roller surface rating.

[0046] The research results of the present invention can be extended and applied to other hot rolling production lines.

[0047] Example 2

[0048] The present invention provides a quantitative evaluation method for the oxide film on a hot-rolled high-speed steel roll. The method is an off-line quantitative evaluation method for the oxide film on the roll. The main steps include: (1) preventing further oxidation of the roll and maintaining the oxide film state on the roll surface during operation; (2) reducing the influence of environmental and measurement conditions; (3) data acquisition; and (4) evaluation.

[0049] In the first step, since the oxidation temperature of high-speed steel rolls is generally above 200°C, the roll surface needs to be sprayed with water for at least 5 minutes after rolling to maintain the oxide film state consistent with that during operation. To prevent the core temperature from being transferred to the roll surface and causing the roll surface temperature to reach the oxidation temperature, the cooling depth needs to be at least 50mm.

[0050] Step 2: To minimize the impact of environmental and measurement conditions and reduce interference, the roller surface temperature is controlled between 30°C and 50°C, preferably 40°C. This ensures both instrument accuracy and minimizes the time it takes for the roller to cool down. (The instruments here refer to spectrophotometers and roughness meters. Excessively high temperatures can affect measurement accuracy, so the temperature must be within the operating range of the equipment.) Before measurement, use a cleaning agent to clean any loose rust and oil stains at the measurement location.

[0051] In the third step, in order to achieve a comprehensive evaluation of the roll surface condition, it is necessary to test different positions of the roll body. First, determine the data collection position on the roll surface. In the roll body direction, the maximum rolling width is used as the data collection area. 30mm is removed on both sides, and data is collected at 5 measurement positions evenly distributed. The Lab color space measurement standard is used at each measurement position to evaluate the surface feature changes of the roll oxide film due to different thickness and composition (L * Parameters: light and dark features, a * Parameters: red and green features, b * Parameter: yellow-blue characteristics). The surface roughness Ra at each measurement location is measured using a roughness meter. The surface roughness Ra is used to comprehensively characterize the growth and spalling characteristics of the oxide film on the roll surface.

[0052] Finally, the data collected in step 3 are used to evaluate the state of the oxide film on the roll surface.

[0053] Table 1 below shows the evaluation of the roll oxide film that cannot be manually evaluated in actual work.

[0054] Table 1 Evaluation of roller oxide film

[0055]

[0056]

[0057] Table 2 Roller surface rating

[0058]

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quantitative evaluation method for oxide film of hot rolling high-speed steel roll, characterized in that: The steps include: Step 1: After stopping rolling, the oxide film state of the roller surface is maintained in the working state to prevent the roller from subsequent oxidation; Step 2: Reduce the impact of the measurement process; Step 3: collect data; Step 3.1, determining the data collection position on the roller surface; Step 3.2, collect color data; Step 3.3, collect roughness data; Step 4: Based on the color data and roughness data collected in step 3, the state of the oxide film on the roller surface is evaluated.

2. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel roll according to claim 1, characterized in that: In the step 1, after stopping rolling, the roller surface is sprayed with water for cooling for more than 5 minutes to reduce the roller surface temperature to below the re-oxidation temperature.

3. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel roll according to claim 2, characterized in that: After water cooling, the roller surface temperature is reduced to below 100°C.

4. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel roll according to claim 2, characterized in that: The cooling depth is above 50mm to prevent the roller surface temperature from being too high due to the temperature transfer from the roller core.

5. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel roll according to claim 1, characterized in that: In step 2, the roller surface temperature is controlled at 30-50° C. during measurement; and before measurement, a cleaning agent is used to clean the rust and oil stains at the measurement position.

6. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel rolls according to claim 5, characterized in that: In step 2, the roller surface temperature is controlled at 40° C. during measurement.

7. The quantitative evaluation method for hot-rolled high-speed steel roll oxide film according to claim 1, characterized in that: In step 3.1, determining the data collection positions on the roller surface includes: taking the maximum rolling width as the data collection area in the roller body direction, removing 30 mm on both sides, and evenly distributing 5 to 8 measurement positions for data collection.

8. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel rolls according to claim 7, characterized in that: In step 3.2, color data collection includes: using Lab color space as the measurement standard, collecting the L * 、a * 、b * Data and record, where L * The parameters are light and dark features, a * The parameters are red and green features, b * The parameters are yellow-blue features.

9. The quantitative evaluation method for the oxide film of hot-rolled high-speed steel rolls according to claim 7, characterized in that: In step 3.3, roughness data collection includes: using a roughness meter with a resolution higher than 0.01 μm to collect and record the roughness data of each measuring position on the roller surface, and using the surface roughness Ra parameter as a characterization to comprehensively characterize the growth and peeling characteristics of the oxide film on the roller surface.

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