A method for preventing a rolling force of a rolling mill from exceeding a limit

Abstract

The application relates to a method for preventing rolling force of a rolling mill from exceeding a limit, belonging to the technical field of steel rolling, and comprising the following steps: detecting the rolling force N of a strip steel during rolling; normally rolling when the rolling force N of the strip steel is less than a first set value N1; closing a part of descaling water of a descaling unit when the rolling force N of the strip steel is greater than the first set value N1; closing another part of descaling water of the descaling unit when the rolling force N of the strip steel is greater than a second set value N2; at least once widening the roll gap of the rolling mill when the rolling force N of the strip steel is greater than a third set value N3; and quickly opening the roll gap of the rolling mill and stopping the rolling mill when the rolling force N of the strip steel is greater than a stop set value N 停 The above design is adopted to reduce the rolling force, so that the intermediate billet rolling force is controlled below the maximum rolling force, the tail rolling force overlarge-caused parking and steel pressing accidents are avoided, the problems of production efficiency caused by the failure of the billet are reduced, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steel rolling, in particular to a method for preventing rolling force of a rolling mill from exceeding a limit. BACKGROUND

[0002] When rolling high-strength steel, the tail of the intermediate billet is subjected to temperature drop for a long time on the delay roller bed. When the temperature of the intermediate billet is too low, the tail rolling force is likely to exceed the design value of the rolling mill, which further causes the fast opening of the roll gap of the rolling mill, the rolling mill stops and the steel is pressed, and the slab is pushed out and other stop rolling accidents occur. This directly affects the production efficiency and the cost indicators such as the yield. For a long time, how to reduce the tail rolling force exceeding the design value of the rolling mill to cause stop accidents has been a key and difficult point, which is directly related to the production efficiency, yield and cost indicators, and is the key to the stability of the finishing rolling and cost control. SUMMARY

[0003] The present application provides a method for preventing the rolling force of a rolling mill from exceeding a limit to avoid the problem of stop accidents caused by the rolling force exceeding the design value of the rolling mill.

[0004] In a first aspect, the present application provides a method for preventing the rolling force of a rolling mill from exceeding a limit.

[0005] Specifically, the rolling system comprises a flying shear unit, a descaling unit and a rolling unit, the rolling unit comprises a rolling mill, and the method comprises:

[0006] In the rolling process, the strip rolling force N is detected;

[0007] When the strip rolling force N is less than a first set value N1, normal rolling is performed;

[0008] When the strip rolling force N is greater than the first set value N1, a part of the descaling water of the descaling unit is closed;

[0009] When the strip rolling force N is greater than a second set value N2, another part of the descaling water of the descaling unit is closed;

[0010] When the strip rolling force N is greater than a third set value N3, the roll gap of the rolling mill is widened at least once;

[0011] When the strip rolling force N is greater than a stop set value N 停 , the roll gap of the rolling mill is controlled to be fast opened and the rolling mill is stopped;

[0012] The first set value N1, the second set value N2, the third set value N3 and the stop set value N 停 satisfy the relationship N1 < N2 < N3 < N 停 ;

[0013] The stop set value N 停and the design maximum rolling force N of the rolling mill 极 satisfies the relationship: N 停 <N 极 .

[0014] As an optional embodiment, the relationship between the first set value N1 and the design maximum rolling force N of the rolling mill 极 satisfies the relationship: N1=N 极 -N 升 , wherein the N 升 is the rising amplitude of the strip rolling force.

[0015] As an optional embodiment, the value of the rising amplitude N 升 of the strip rolling force is 6000-9000 KN.

[0016] As an optional embodiment, when the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened at least once, specifically comprising:

[0017] when the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened for the first time;

[0018] when the strip rolling force N is greater than the fourth set value N4, the roll gap of the rolling mill is widened for the second time;

[0019] wherein the relationship between the fourth set value N4 and the third set value N3, the shutdown set value N 停 satisfies the relationship: N3 停 .

[0020] As an optional embodiment, the first set value N1 is 40000-41000 KN.

[0021] As an optional embodiment, the second set value N2 is 43000-44000 KN.

[0022] As an optional embodiment, the third set value N3 is 45000-46000 KN.

[0023] As an optional embodiment, the fourth set value N4 is 47000-48000 KN.

[0024] As an optional embodiment, the first widening value of the roll gap is 0.5-1.5 mm; and / or

[0025] the second widening value of the roll gap is 0.5-1.5 mm.

[0026] As an optional implementation, the timing of detecting the strip rolling force N is when the strip is rolled to a tail section of the strip, the tail section of the strip being a section of the strip between the flying shear unit and the rolling unit.

[0027] Compared with the prior art, the above technical solution provided by the embodiments of the present application has the following advantages:

[0028] The method provided by the embodiments of the present application detects the rolling force of the strip during rolling. When the rolling force exceeds a set value, the rolling force is reduced by reducing the descaling water and expanding the roll gap to reduce the rolling mill load, so that the intermediate blank rolling force is controlled below the maximum rolling force, the stop-rolling and steel pressing accident caused by excessive tail rolling force is avoided, the problems of pushing waste slabs caused by faults and affecting production efficiency are reduced, and the cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0031] Figure 1 The structural schematic diagram of the rolling system provided by the embodiments of the present application is shown in the figure;

[0032] Figure 2 The flowchart of the method provided by the embodiments of the present application is shown in the figure;

[0033] Reference signs:

[0034] Reference sign 1 represents a flying shear inlet roller, which is used to transport the intermediate blank to the flying shear position;

[0035] Reference sign 2 represents a crank-type flying shear, which is used to cut off the irregular shape of the head and tail of the intermediate blank;

[0036] Reference sign 3 represents a descaling header, including an inlet and outlet descaling header, which is used for high-pressure water to remove the oxide scale on the surface of the intermediate blank;

[0037] Reference sign 4 represents a descaling machine, which is a descaling system device;

[0038] Reference sign 5 represents an inlet descaling header;

[0039] Reference sign 6 represents an outlet descaling header;

[0040] Reference 7 represents: finishing mill, for rolling the intermediate blank to the finished thickness;

[0041] Reference 8 represents: rolling direction. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0043] Unless otherwise specifically indicated, all the various raw materials, reagents, instruments and equipment and the like used in the present application can be purchased from the market or can be prepared by the existing method.

[0044] The embodiments of the present application provide a method for preventing rolling force of a rolling mill from exceeding the limit, as shown in Figure 1 The rolling system comprises a flying shear unit, a descaling unit and a rolling unit, as shown in Figure 2 The rolling unit comprises a rolling mill, and the method comprises:

[0045] S1. detecting the strip rolling force N during rolling;

[0046] In the present embodiment, the rolling force detection is performed by a pressure head installed below the lower support roll of the rolling mill;

[0047] S2. when the strip rolling force N is less than a first set value N1, normally rolling;

[0048] S3. when the strip rolling force N is greater than the first set value N1, closing a part of the descaling water of the descaling unit;

[0049] S4. when the strip rolling force N is greater than a second set value N2, closing another part of the descaling water of the descaling unit;

[0050] S5. when the strip rolling force N is greater than a third set value N3, widening the roll gap of the rolling mill at least once;

[0051] In some embodiments, when the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened at least once, specifically comprising:

[0052] when the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened for the first time;

[0053] when the strip rolling force N is greater than a fourth set value N4, the roll gap of the rolling mill is widened for the second time;

[0054] wherein the fourth set value N4 and the third set value N3, the shutdown set value N 停 satisfy the relationship: N3 停 .

[0055] Further, the first expansion value of the roll gap is 0.5-1.5mm; and / or

[0056] the second expansion value of the roll gap is 0.5-1.5mm.

[0057] In the embodiment, the roll gap of the rolling mill is controlled by a hydraulic cylinder, and a magnetic scale is installed on the hydraulic cylinder to measure the roll gap of the rolling mill.

[0058] S6. When the strip rolling force N is greater than the shutdown set value N 停 , the roll gap of the rolling mill is quickly opened, and the rolling mill is stopped;

[0059] The first set value N1, the second set value N2, the third set value N3 and the shutdown set value N 停 satisfy the relationship: N1 停 .

[0060] The shutdown set value N 停 and the designed maximum rolling force N 极 of the rolling mill satisfy the relationship: N 停 极 .

[0061] In some embodiments, the first set value N1 and the designed maximum rolling force N 极 of the rolling mill satisfy the relationship: N1=N 极 -N 升 , wherein the N 升 is the rising amplitude of the strip rolling force.

[0062] Generally, the rising amplitude N 升 of the strip rolling force is 6000-9000KN.

[0063] Based on the current shutdown set value N 停 of the rolling mill, which is generally 50000KN, in the embodiment, the first set value N1 is 40000-41000KN; the second set value N2 is 43000-44000KN; the third set value N3 is 45000-46000KN; and the fourth set value N4 is 47000-48000KN.

[0064] ​Generally, the problem of excessive rolling force only occurs when the strip is rolled to the tail section, so in this application, the timing of detecting the strip rolling force N is when the strip is rolled to the tail section of the strip, which is the section between the flying shear unit and the rolling unit when the flying shear unit cuts the tail of the intermediate blank.

[0065] The above method can be written into a program module, and the program module can be added to the rolling system to realize the above steps.

[0066] The application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application. The experimental methods not specified in the following examples are generally determined according to the national standards. If there is no corresponding national standard, the general international standard, the conventional condition, or the condition suggested by the manufacturer is used.

[0067] Example 1

[0068] A method for preventing the quick opening of the rolling force of a rolling mill, comprising the following steps:

[0069] First, the strip is rolled in the finishing rolling, and when the tail of the intermediate blank passes through the flying shear, the flying shear cuts the tail of the intermediate blank;

[0070] The crank-type flying shear is pre-tilted to 310° as the starting position; when the flying shear performs the tail cutting action, the linear speed of the flying shear during cutting is less than the running speed of the intermediate blank, and the cutting speed of the flying shear lags behind the running speed of the intermediate blank by a certain lag rate, and the lag rate ranges from 0% to 10%.

[0071] When the tail of the intermediate blank is cut, if the strip rolling force exceeds 41,000 KN, the inlet descaling of the finishing descaler is closed;

[0072] If the strip rolling force exceeds 41,000 KN, after the inlet descaling of the finishing descaler is closed, if the strip rolling force continues to rise and exceeds 44,000 KN, the outlet descaling of the finishing descaler is closed again;

[0073] When the inlet and outlet descalings of the finishing descaler are closed, if the strip rolling force continues to rise and exceeds 46,000 KN, the roll gap is lifted by 1 mm;

[0074] After the roll gap is lifted by 1 mm, if the strip rolling force continues to rise and exceeds 48,000 KN, the roll gap is lifted by 1 mm again;

[0075] If the strip rolling force exceeds 50,000 KN, the roll gap is quickly opened, and the rolling mill is stopped.

[0076] When the rolling force exceeds a given value, the rolling force is reduced by reducing the tail temperature drop, closing the fine descaling inlet and outlet headers, and opening the roll gap to reduce the rolling mill load, so that the intermediate slab rolling force is controlled below the maximum rolling force, the tail rolling force is prevented from being too large to cause a stop-rolling-steel accident, the production efficiency is improved by reducing the problems of pushing waste slabs caused by failures, and the cost is reduced.

[0077] Various embodiments of the present application can exist in a range of forms; it should be understood that the description in a range form is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the described range has disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single values within the described range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) within the indicated range.

[0078] In this application, the orientation words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings, unless otherwise stated. In addition, in the description of the specification of this application, the terms "include", "contain" and the like mean "include but are not limited to". In this document, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations have any such actual relationship or order. In this document, "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the cases of A alone, A and B together, and B alone. Where A and B can be singular or plural. In this document, "one or more" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0079] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A method for preventing excessive rolling force in a rolling mill, characterized in that, The rolling system includes: a flying shear unit, a descaling unit, and a rolling unit, wherein the rolling unit includes a rolling mill, and the method includes: During the rolling process, the rolling force N of the strip is measured; When the strip rolling force N is less than the first set value N1, normal rolling is performed; When the strip rolling force N is greater than the first set value N1, a portion of the descaling water in the descaling unit is shut off; When the strip rolling force N is greater than the second set value N2, the other part of the descaling water in the descaling unit is shut off; When the strip rolling force N is greater than the third set value N3, the roll gap of the mill shall be widened at least once. When the strip rolling force N is greater than the shutdown setting value N 停 At that time, the roll gap of the control mill is quickly opened, and the mill stops; The first setting value N1, the second setting value N2, the third setting value N3, and the shutdown setting value N 停 The order of magnitudes satisfies: N1 < N2 < N3 < N 停 ; The shutdown setting value N 停 and the maximum design rolling force N of the rolling mill 极 The size relationship satisfies: N 停 <N 极 ; The timing for detecting the strip rolling force N is when the strip is rolled to the tail section of the strip, which is the strip section between the flying shear unit and the rolling unit when the flying shear unit performs intermediate billet tail cutting; When the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened at least once, specifically including: When the strip rolling force N is greater than the third set value N3, the roll gap of the rolling mill is widened for the first time. When the strip rolling force N is greater than the fourth set value N4, the roll gap of the rolling mill is widened a second time. Fourth setting value N4, third setting value N3, and shutdown setting value N 停 The relation satisfies: N3 < N4 < N 停 ; The first setting value N1 is 40000-41000KN, the second setting value N2 is 43000-44000KN, the third setting value N3 is 45000-46000KN, and the fourth setting value N4 is 47000-48000KN; The roll gap of the rolling mill is controlled by a hydraulic cylinder, which is equipped with a magnetic scale for measuring the roll gap. The first set value N1 and the design maximum rolling force N of the rolling mill 极 The relation satisfies: N1 = N 极 -N 升 , wherein, the N 升 The increase in strip rolling force; The increase in strip rolling force N 升 The value is 6000-9000KN.

2. The method for preventing excessive rolling force in a rolling mill according to claim 1, characterized in that, The initial widening of the roll gap is 0.5-1.5 mm; and / or The second widening of the roll gap is 0.5-1.5 mm.

Images