Method for improving axial non-uniform stripping of oxidation film of hot continuous rolling high-speed steel roller

Abstract

The invention provides a method for improving axial non-uniform stripping of an oxidation film of a hot continuous rolling high-speed steel roller. The method comprises the following steps that 1, the width specification range of a rolled product is determined according to a rolling plan in a period; 2, the roller is partitioned in the axial direction of the roller according to the product width; 3, the cooling water amount of the corresponding area is calculated according to the roller subareas; and 4, roller ironing is conducted, normal production is conducted, and the roller is cooled on the basis of the cooling water amount, calculated in the step 3, of all the areas of the roller. The axial abnormal stripping condition of the roller surface of the roller can be obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to a method for improving the uneven axial peeling of an oxide film on a hot-rolled high-speed steel roller. Background Art

[0002] During the hot rolling process, since the temperature in the middle of the strip is high and the temperature at the edge is low, long-term contact with the roll will inevitably lead to high temperature in the middle of the roll and low temperature at the edge. When the temperature difference is too large, it will inevitably lead to uneven growth of the axial oxide film of the roll, resulting in abnormal peeling, affecting the service life of the roll and product quality.

[0003] To address this issue, a Chinese patent document with publication number CN105710131A discloses a method for axially distributing the outlet water volume of the cooling water for hot rolling mill rolls. Its main feature is that the outlet cooling water volume is increased to 70% to 90% of the total water volume, the inlet water volume is evenly distributed, the outlet water volume is distributed in a step-like manner, and the calculation rules are complex. A Chinese patent document with publication number CN203678851U discloses a cooling device for generating an oxide film on a roll. Its main feature is that it provides a cooling device with nozzles parabolically distributed along the axis of the roll. The nozzles are arranged in two rows, upper and lower, with an angle between the upper and lower nozzles of 15° to 35°, which can uniformly cool the roll surface. This method not only requires additional costs, but its installation and use are also easily restricted by on-site conditions (on-site installation space and pipeline layout, etc.). Summary of the Invention

[0004] In response to the aforementioned technical problems, a method is provided to improve the uneven axial peeling of the oxide film on hot-rolled high-speed steel rolls. The present invention primarily utilizes a method of using different cooling rates along the roll axis to improve the axial temperature uniformity of the roll, thereby improving the uneven axial peeling of the oxide film on the roll.

[0005] The technical means adopted in the present invention are as follows:

[0006] A method for improving the uneven axial peeling of the oxide film of a hot-rolled high-speed steel roll comprises the following steps:

[0007] Step 1: Confirm the width specification range of the rolled product according to the rolling plan within the cycle;

[0008] Step 2: partition the rollers along the roller axis according to the product width;

[0009] Step 3: Calculate the cooling water volume of the corresponding area according to the roller partition;

[0010] Step 4: hot the rolls, and then continue normal production. The rolls are cooled based on the cooling water volume in each area of ​​the rolls calculated in step 3.

[0011] Furthermore, in step 2, the center of the workpiece is made to coincide with the center of the roll, and the roll is divided into zones along the axial direction: the area occupied by the minimum rolled width is the constant contact area, the area occupied by the difference between the maximum rolled width and the minimum rolled width is the width-varying contact area, and there are two width-varying contact areas, which are symmetrically located on the left and right sides of the constant contact area; the area greater than the maximum rolled width is the non-contact area, and there are two non-contact areas, which are symmetrically located on the left and right sides of the width-varying contact area;

[0012] The zones on the roller are from left to right: non-contact zone, width-varying contact zone, constant contact zone, width-varying contact zone, and non-contact zone.

[0013] Furthermore, the amount of cooling water in the width-varying contact area is greater than the amount of cooling water in the constant contact area, and the amount of cooling water in the constant contact area is greater than the amount of cooling water in the non-contact area.

[0014] Furthermore, in step 3, different partitions of the roller body have different weight coefficients, wherein the weight coefficient of the constant contact area is 1.0, the weight coefficient of the width-varying contact area is 1.1, and the weight coefficient of the non-contact area is 0.5; the amount of water allocated to each partition is obtained based on the weight coefficients of the three partitions, the lengths of the three partitions, and the total water volume.

[0015] Furthermore, the total water volume in the length direction of the roller body is controlled at 750m 3 / h~850m 3 / h.

[0016] Furthermore, the total water volume in the length direction of the roller body is controlled at 800m 3 / h.

[0017] Furthermore, the axial temperature difference of the roller body is reduced to within 20°C.

[0018] Furthermore, in step 4, a hot roller process is used to form a uniform and dense oxide film on the surface of the roller: a product with a room temperature yield strength lower than 240 MPa is used as the hot roller material, 2 to 3 pieces of rolled material are used in the initial stage of rolling, roller cooling water is disabled, and the rolling rhythm is 3 to 4 minutes per piece for hot roller.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention provides a method for improving the uneven axial spalling of oxide films on hot-rolled high-speed steel rollers. The rollers are divided axially into a constant contact zone, a variable-width contact zone, and a non-contact zone based on their different temperature and stress characteristics. In the non-contact zone, the water volume is reduced to concentrate cooling capacity toward the center. In the variable-width contact zone, where abnormal shear forces often occur due to deviations in edge shape, the present invention increases the water volume to reduce oxide film thickness, thereby improving bonding strength and reducing spalling probability. In the constant contact zone, a relatively strong cooling intensity is maintained, keeping the roller surface temperature constant, thereby reducing abnormal spalling caused by variations in oxide film growth rate.

[0021] 2. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roller provided by the present invention can significantly improve the abnormal axial peeling of the roller surface after implementation, and reduce the roller consumption from 0.12kg / t to 0.062kg / t.

[0022] Based on the above reasons, the present invention can be widely promoted in the field of improving abnormal peeling of roller oxide film. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1 Flowchart of the method of the present invention.

[0025] Figure 2 This is a diagram of the cooling water distribution in each zone of the roller body of the present invention.

[0026] Figure 3 Schematic diagram of the roller face comparison under typical working conditions, where (a) is before process improvement and (b) is after process improvement. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The technical problem addressed by the present invention is the uneven axial temperature distribution of the rolls during hot rolling, which leads to different growth rates of the oxide film at different locations on the roll body and causes abnormal flaking. The present invention utilizes a method of using different cooling rates in different zones along the roll axis to improve the axial temperature uniformity of the rolls, thereby improving the uneven flaking of the oxide film along the roll axis.

[0032] This invention addresses the problem of abnormal axial flaking of the roller oxide film, arguing that the primary cause is inadequate cooling intensity. The water volume should be appropriately increased in the central constant contact section. However, since the production process often utilizes roll bending and shifting, the contact center position is not constant, so excessive zoning of the central section should be avoided. In the variable-width contact area when rolling products of varying widths, where shear stress is high, a higher water volume should be used to reduce the thickness of the roller oxide film and increase bonding strength. In non-contact areas, the water volume should be reduced to conserve water.

[0033] The present invention provides a method for improving the uneven axial peeling of the oxide film of a hot-rolled high-speed steel roll, comprising the following steps:

[0034] The first step is to find the product width specification range according to the rolling plan within the cycle. The purpose of clarifying the product specification range is to confirm the maximum and minimum width of the rolling. Here, the width of the product refers to the width of the strip.

[0035] The second step is to partition the rolls along the roll axis according to the product width;

[0036] The third step is to calculate the cooling water volume of the corresponding area according to the roller partition;

[0037] The fourth step is to hot the rolls, resume normal production, and cool the rolls based on the cooling water volume in each area of ​​the rolls calculated in the third step.

[0038] The method of the present invention specifically comprises the following steps:

[0039] S1. Use a suitable hot roller process to form a uniform and dense oxide film on the surface of the roller. Specifically, use products with a room temperature yield strength lower than 240MPa (the product here refers to steel coils, specifically refers to the transition of steel coils with lower strength levels produced first) as hot roller materials. Use 2 to 3 pieces of rolled materials at the initial stage of rolling. Disable the use of roller cooling water. Hot rollers are performed at a rolling rhythm of 3 to 4 minutes per piece. First, a uniform and dense oxide film is formed on the surface of the roller by hot rollers. After the oxide film is formed, the rollers are used for normal production and rolling. During the rolling process, cooling water is used to cool each partition of the roller. It should be noted that the initially established oxide film must be dense, and the generation of abnormal oxide film must be controlled during the rolling process in order to improve uneven peeling.

[0040] S2. Align the center of the workpiece with the center of the roll, and divide the roll into axial sections. The area occupied by the minimum rolled width is the constant contact zone; the area defined by the difference between the maximum and minimum rolled widths is the variable width contact zone. There are two variable width contact zones, symmetrically located on the left and right sides of the constant contact zone. The area greater than the maximum rolled width is the non-contact zone, and there are two non-contact zones, symmetrically located on the left and right sides of the variable width contact zone. The sections on the roll, from left to right, are: non-contact zone, variable width contact zone, constant contact zone, variable width contact zone, and non-contact zone.

[0041] S3. Control the total water volume in the roller length direction to 750m 3 / h~850m 3 / h, preferably 800m 3 / h.

[0042] Furthermore, the amount of cooling water in the width-varying contact zone is greater than that in the constant contact zone, and the amount of cooling water in the constant contact zone is greater than that in the non-contact zone. Different weight coefficients are assigned to different zones of the roll body, where the weight coefficient of the constant contact zone is 1.0, the weight coefficient of the width-varying contact zone is 1.1, and the weight coefficient of the non-contact zone is 0.5. The corresponding amount of water allocated to each zone can be obtained based on the weight coefficients of the three zones, the lengths of the three zones, and the total water volume. The purpose is to concentrate the water volume in the middle and moderately increase the cooling intensity at the width edge of the strip to reduce the oxide film thickness in the width-varying contact zone. Among them, the water volume of each zone = zone length × (total water volume / (constant contact zone length × constant contact zone weight coefficient + width-varying contact zone length × width-varying contact zone weight coefficient + non-contact zone length × non-contact zone weight coefficient) × zone weight coefficient.

[0043] Furthermore, the axial temperature difference of the roller body (the difference between the maximum temperature and the minimum temperature of each zone of the roller body) is reduced to within 20°C.

[0044] Before implementation, the rolls are usually not zoned. The typical roll cooling water volume is 700m 3 / h and 1000m 3 / h.

[0045] Table 1 Comparison of typical processes

[0046]

[0047] Table 2 Comparison of roller consumption before and after implementation

[0048] name Roller consumption before implementation (kg / t) Roller consumption after implementation (kg / t) Finishing high speed steel work roll 0.12 0.062

[0049] The present invention can be extended and applied to other hot rolling production lines.

[0050] 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 method for improving the uneven axial peeling of the oxide film on a hot-rolled high-speed steel roll, characterized in that: The steps include: Step 1: Confirm the width specification range of the rolled product according to the rolling plan within the cycle; Step 2: partition the rollers along the roller axis according to the product width; Step 3: Calculate the cooling water volume of the corresponding area according to the roller partition; Step 4: hot the rolls, and then continue normal production. The rolls are cooled based on the cooling water volume in each area of ​​the rolls calculated in step 3.

2. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 1, characterized in that: In step 2, the center of the workpiece is made to coincide with the center of the roll, and the roll is divided into zones along the axial direction: the area occupied by the minimum rolled width is the constant contact zone, the area occupied by the difference between the maximum rolled width and the minimum rolled width is the width-varying contact zone, and there are two width-varying contact zones, which are symmetrically located on the left and right sides of the constant contact zone; the area greater than the maximum rolled width is the non-contact zone, and there are two non-contact zones, which are symmetrically located on the left and right sides of the width-varying contact zone; The zones on the roller are from left to right: non-contact zone, width-varying contact zone, constant contact zone, width-varying contact zone, and non-contact zone.

3. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 2, characterized in that: The amount of cooling water in the width-varying contact area is greater than the amount of cooling water in the constant contact area, and the amount of cooling water in the constant contact area is greater than the amount of cooling water in the non-contact area.

4. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 3, characterized in that: In step 3, different partitions of the roller body have different weight coefficients, wherein the weight coefficient of the constant contact area is 1.0, the weight coefficient of the width-varying contact area is 1.1, and the weight coefficient of the non-contact area is 0.5; the water volume allocated to each partition is obtained based on the weight coefficients of the three partitions, the lengths of the three partitions, and the total water volume.

5. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 1, characterized in that: The total water volume along the roller length is controlled at 750m 3 / h~850m 3 / h.

6. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 5, characterized in that: The total water volume along the roller length is controlled at 800m 3 / h.

7. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 1, characterized in that: The axial temperature difference of the roller body is reduced to within 20℃.

8. The method for improving the uneven axial peeling of the oxide film on the hot-rolled high-speed steel roll according to claim 2, characterized in that: In step 4, a hot roller process is used to form a uniform and dense oxide film on the surface of the roller: a product with a room temperature yield strength lower than 240 MPa is used as the hot roller material, 2 to 3 pieces of rolled material are used at the initial stage of rolling, cooling water for the roller is disabled, and the rolling rhythm is 3 to 4 minutes per piece for hot roller.

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