Cooling water control method for pre-oxidized high-speed steel rolls during rolling.

Abstract

This invention relates to a method for controlling the cooling water volume of pre-oxidized high-speed steel rolls during the rolling of hot rolls, belonging to the technical field of control methods applicable to metal rolling mills. The method first calculates the target rolling pressure range using the rolling pressure recorded under n rolling plans for normal, non-pre-oxidized high-speed steel rolls. Then, it calculates the required cooling water volume for the pre-oxidized high-speed steel rolls. During the rolling of hot rolls with the pre-oxidized high-speed steel rolls, the rolling pressure is recorded and it is determined whether it falls within the target rolling pressure range. This determines whether the calculated cooling water volume remains unchanged. If it does, a new cooling water volume is recalculated, and this process is repeated until a suitable cooling water volume is selected. This method simultaneously correlates the roll thermal crown with both rolling pressure and cooling water volume. It judges and controls the change in roll thermal crown by whether the rolling pressure of the pre-oxidized high-speed steel roll during the rolling of hot roll material falls within the target rolling pressure range.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of hot rolling preformed oxide film finishing high speed steel roll in the control method of roll thermal crown when rolling hot roll, especially to a kind of method for controlling the roll thermal crown of preformed oxide film finishing high speed steel roll in the stage of rolling hot roll by controlling cooling water amount, belong to the control method technical field suitable for metal rolling mill. BACKGROUND

[0002] Preform oxide film on the surface of high speed steel roll using laser technology, has obvious peeling advantage, can avoid the surface oxide film peeling of traditional high speed steel roll when producing high-strength thin plate.But because the heat conduction of oxide film has obvious gap compared with high speed steel material, its result is that the thermal expansion speed of preformed oxide film roll is smaller than normal high speed steel roll in the process of starting rolling, i.e.hot roll, compared with the hot roll of normal high speed steel roll, the thermal crown of preformed oxide film roll will be insufficient, and the hot roll effect is poor, thereby affecting the shape control when rolling.Therefore, for preformed oxide film roll, additional hot roll is needed, but it will affect enterprise benefit. SUMMARY

[0003] The technical problem to be solved by the present application is how to make the preformed oxide film roll reach the same roll thermal crown as normal high speed steel roll in the stage of rolling hot roll.

[0004] The technical solution proposed by the present application to solve the above technical problem is: a kind of cooling water amount control method of preformed oxide film high speed steel roll when rolling hot roll, executes the following steps:

[0005] 1) in the rolling of normal high speed steel roll without preformed oxide film, select 10-20 rolling plans, after completing the hot roll rolling of 5 strips in each rolling plan, run at normal calibration speed, adjust the roll gap to 1mm, and record the rolling pressure at this time, record 10-20 times of rolling pressure in total in 10-20 rolling plans, take the maximum value Fmax and minimum value Fmin of the 10-20 times of rolling pressure, and calculate the average value Fave of the 10-20 times of rolling pressure at the same time;

[0006] 2) calculate the rolling pressure target range when running at normal calibration speed and the roll gap is 1mm, the lower limit of rolling pressure target range F1=(Fave+Fmin) / 2, the upper limit of target F2=(Fmax+Fave) / 2, to characterize the range of roll thermal crown of preformed oxide film high speed steel roll in the stage of rolling hot roll by rolling pressure target range;

[0007] 3) calculate the roll cooling water amount A required by preformed oxide film high speed steel roll according to the following formula (1),

[0008] A=(a1+a2) / 2 (1),

[0009] a1 is the normal roll cooling water quantity of the high speed steel roll without pre-oxidation film during the rolling and heating-up stage, a2 is the minimum roll cooling water quantity of the high speed steel roll without pre-oxidation film during the rolling and heating-up stage, and a2 = 70% * a1 is generally taken;

[0010] 4) When the high speed steel roll with pre-oxidation film is used for rolling and heating-up, the roll cooling water quantity is configured according to A, and when the normal 5 pieces of strip are rolled and heated-up, the roll gap is adjusted to 1 mm, and the rolling pressure f0 at this time is recorded;

[0011] If f0 falls within the rolling pressure target range F1-F2, A is selected as the roll cooling water quantity of the high speed steel roll with pre-oxidation film during the rolling and heating-up stage, and the process directly proceeds to step 7;

[0012] If f0 does not fall within the rolling pressure target range F1-F2, the process proceeds to the next step;

[0013] 5) If f0 < F1, a1 = A, a2 is unchanged, and the new roll cooling water quantity A1 = (A + a2) / 2 of the high speed steel roll with pre-oxidation film during the rolling and heating-up stage is calculated according to formula (1);

[0014] If f0 > F2, a2 = A, a1 is unchanged, and the new roll cooling water quantity A2 = (a1 + A) / 2 of the high speed steel roll with pre-oxidation film during the rolling and heating-up stage is calculated according to formula (1);

[0015] 6) Step 4 is repeated, and the roll cooling water quantity is configured according to A1 or A2 when the high speed steel roll with pre-oxidation film is used for rolling and heating-up again, and when the normal 5 pieces of strip are rolled and heated-up, the roll gap is adjusted to 1 mm, and the rolling pressure f1 or f2 at this time is recorded. If f1 or f2 falls within the rolling pressure target range F1-F2, A1 or A2 is selected as the roll cooling water quantity of the high speed steel roll with pre-oxidation film during the rolling and heating-up stage,

[0016] If f1 or f2 does not fall within the rolling pressure target range F1-F2, step 5 is repeated;

[0017] The process is repeated until the roll cooling water quantity of the high speed steel roll with pre-oxidation film during the rolling and heating-up stage is selected;

[0018] 7) After the high speed steel roll with pre-oxidation film is rolled and heated-up, the roll cooling water quantity of the high speed steel roll with pre-oxidation film during the subsequent rolling is restored to a1 in step 3.

[0019] This invention first selects the maximum, minimum, and average rolling pressure values ​​under n rolling plans during the rolling of normal high-speed steel rolls without pre-oxidized coating (under specific conditions, i.e., after completing the hot roll rolling of 5 strips within one rolling plan, operating at the normal calibrated speed, and adjusting the roll gap to 1mm). The target range of rolling pressure (under these conditions) is calculated, and this target range is used to characterize the range of roll thermal crown during the hot roll rolling stage of the pre-oxidized coating high-speed steel roll. Then, the required roll cooling water volume for the pre-oxidized coating high-speed steel roll is calculated and used as the roll cooling water volume during the hot roll rolling process. When the pre-oxidized coating high-speed steel roll... After the steel roll completes the normal rolling of five strip steel hot rolls, the rolling pressure at that time is recorded under the same conditions. Based on whether the rolling pressure at that time is within the target range of rolling pressure, it is determined whether to use the previously calculated roll cooling water volume as the roll cooling water volume during the hot roll rolling of the pre-oxidized high-speed steel roll. If it changes, the roll cooling water volume is recalculated and a new roll cooling water volume is set. This process is repeated until the roll cooling water volume during the hot roll rolling of the pre-oxidized high-speed steel roll is selected. Finally, after the pre-oxidized high-speed steel roll is completed during the hot roll rolling, the roll cooling water volume during the subsequent rolling of the pre-oxidized high-speed steel roll is restored to the roll cooling water volume during normal rolling.

[0020] The beneficial effects of this invention are: Under specific conditions (i.e., after rolling 5 strips of hot rolls within a rolling plan, operating at the normal calibrated speed, and adjusting the roll gap to 1mm), the change in roll thermal crown is directly related to the rolling pressure. Therefore, the target range of rolling pressure under these conditions can be directly used to characterize the range of roll thermal crown. Furthermore, the change in roll thermal crown is also directly related to the amount of roll cooling water; that is, controlling the amount of roll cooling water can control the change in roll thermal crown. To ensure the pre-formed oxide film... The roll achieves the same thermal crown as a normal high-speed steel roll during the hot rolling stage. By adjusting the cooling water volume of the pre-oxidized high-speed steel roll during the hot rolling stage, and considering whether the rolling pressure of the pre-oxidized high-speed steel roll during the hot rolling stage falls within the target range of rolling pressure (i.e., the range of roll thermal crown), the range of roll thermal crown variation can be determined and controlled. This allows the roll thermal crown to be controlled to achieve the same thermal crown as a normal high-speed steel roll during the hot rolling stage, i.e., the same hot rolling effect. Detailed Implementation Example 1

[0021] This embodiment describes a method for controlling the cooling water volume of pre-oxidized high-speed steel rolls during the rolling process. Taking the finishing mill of a 1780 hot rolling production line as an example, the rated speed of the 1780 hot rolling finishing mill F1 is 200 m / min, and the normal roll cooling water volume is 1230 m³ / min. 3 / h. Perform the following steps:

[0022] 1) In the rolling of high-speed steel rolls without pre-formed oxide film, 10 rolling plans were selected. After the hot rolls of 5 strip steels were rolled in each rolling plan, the rolls were operated at the normal calibrated speed of 200m / min. The roll gap was adjusted to 1mm, and the rolling pressure was recorded. A total of 10 rolling pressures were recorded for the 10 rolling plans. The maximum value Fmax = 710 tons and the minimum value Fmin = 550 tons of these 10 rolling pressures were taken. At the same time, the average value Fave = 620 tons of these 10 rolling pressures was calculated.

[0023] 2) Calculate the target range of rolling pressure when operating at the normal calibrated speed of 200m / min and with a roll gap of 1mm. The lower limit of the target range of rolling pressure is F1 = (Fave + Fmin) / 2 = 585 tons, and the upper limit is F2 = (Fmax + Fave) / 2 = 665 tons. The target range of rolling pressure is used to characterize the range of roll thermal crown of the pre-oxidized high-speed steel roll during the rolling hot roll stage.

[0024] 3) Calculate the required cooling water volume A for the pre-oxidized high-speed steel roll according to the following formula (1).

[0025] A = (a1 + a2) / 2 (1),

[0026] In formula (1), a1 is the normal cooling water volume of the high-speed steel roll without pre-coated oxide film during the rolling hot roll stage, i.e., a1 = 1230m. 3 / h, where a2 is the minimum roll cooling water volume for high-speed steel rolls without pre-oxidized film during the rolling and hot-rolling stage, generally taken as a2=70% * a1=861 m 3 If the value is / h, then A = (1230 + 861) / 2 = 1045.5 m 3 / h;

[0027] 4) When using pre-oxidized high-speed steel rolls for hot rolling, follow the formula A, i.e., 1045.5 m. 3 / h Configure the roll cooling water volume. After completing the normal rolling of 5 strip steel hot rolls, operate at the normal calibrated speed of 200m / min, adjust the roll gap to 1mm, and record the rolling pressure f0 at this time as 650 tons. Since 650 tons is within the range of 585-665 tons, select A (1045.5 m 3 / h) The cooling water volume remains unchanged during hot rolling of high-speed steel rolls with pre-oxidized film;

[0028] 5) After the pre-oxidized high-speed steel rolls are rolled on 5 strips of hot rolls, the cooling water volume of the rolls during subsequent rolling is restored to the initial a1 (1230m) in step 3). 3 / h. Example 2

[0029] This embodiment describes a method for controlling the cooling water volume of pre-oxidized high-speed steel rolls during the rolling process. Taking a 1780 hot rolling production line finishing mill as an example, the rated speed of the 1780 hot rolling finishing mill F4 is 200 m / min, and the normal roll cooling water volume is 1150 m³ / min. 3 / h. Perform the following steps:

[0030] 1) In the rolling of high-speed steel rolls without pre-formed oxide film, 15 rolling plans were selected. After the hot rolls of 5 strip steels were rolled in each rolling plan, the rolls were operated at the normal calibration speed of 200m / min. The roll gap was adjusted to 1mm, and the rolling pressure was recorded. A total of 15 rolling pressures were recorded for the 15 rolling plans. The maximum value Fmax = 700 tons and the minimum value Fmin = 540 tons of these 15 rolling pressures were taken. At the same time, the average value Fave = 610 tons of these 15 rolling pressures was calculated.

[0031] 2) Calculate the target range of rolling pressure when operating at the normal calibration speed of 200m / min and with a roll gap of 1mm. The lower limit of the target range of rolling pressure is F1=(Fave+Fmin) / 2=575, and the upper limit of the target range is F2=(Fmax+Fave) / 2=655. The target range of rolling pressure is used to characterize the range of roll thermal crown of the pre-oxidized high-speed steel roll during the rolling hot roll stage.

[0032] 3) Calculate the required cooling water volume A for the pre-oxidized high-speed steel roll according to the following formula (1).

[0033] A = (a1 + a2) / 2 (1),

[0034] In formula (1), a1 is the normal cooling water volume of the high-speed steel roll without pre-coated oxide film during the rolling hot roll stage, i.e., a1 = 1150 m³ / s. 3 / h, where a2 is the minimum roll cooling water volume for high-speed steel rolls without pre-oxidized film during the rolling and hot-rolling stage, generally taken as a2=70% * a1=805 m 3 If the value is / h, then A = (1150 + 805) / 2 = 977.5m 3 / h;

[0035] 4) When using pre-oxidized high-speed steel rolls for hot rolling, follow the procedure A, i.e., 977.5m. 3 / h Configure the cooling water volume of the rolls. After the normal rolling of 5 strip hot rolls is completed, run at the normal calibrated speed of 200m / min and adjust the roll gap to 1mm. Record the rolling pressure f0 at this time as 570 tons. Since 570 tons is not within the range of 575-655 tons, proceed to the next step.

[0036] 5) Since 570 < 575, take a1 = A = 977.5m 3 / h, a2 remains unchanged, and the new roll cooling water volume A1 = (A + a2) / 2 = (977.5 + 805) / 2 = 891.25 m³ is recalculated according to formula (1) during the hot roll rolling of the pre-oxidized high-speed steel roll. 3 / h

[0037] 6) Repeat step 4), and when rolling with pre-oxidized high-speed steel rolls on hot rolls again, follow A1, i.e., 891.25 m. 3 Configure the roll cooling water volume by / h. After completing the normal rolling of 5 strip hot rolls, operate at the normal calibrated speed of 200m / min, adjust the roll gap to 1mm, and record the rolling pressure f1 at this time as 585 tons. Since 585 tons is within the range of 575-655 tons, select A1, which is 891.25 m. 3 / h is used as the pre-oxidized film high-speed steel roll cooling water volume during hot roll rolling;

[0038] 7) After the pre-oxidized high-speed steel rolls are rolled on hot rolls, the cooling water volume of the rolls during subsequent rolling processes is restored to the initial a1 (1150m) in step 3). 3 / h.

[0039] Obviously, if f1 in step 6) does not fall within the rolling pressure target range F1-F2, then repeat step 5).

[0040] This process is repeated until the required amount of cooling water for the pre-oxidized high-speed steel rolls during hot rolling is determined. Example 3

[0041] This embodiment describes a method for controlling the cooling water volume of pre-oxidized high-speed steel rolls during the rolling process. Taking a 1780 hot rolling production line finishing mill as an example, the rated speed of the 1780 hot rolling finishing mill F2 is 200 m / min, and the normal roll cooling water volume is 1320 m³ / min. 3 / h. Perform the following steps:

[0042] 1) In the rolling of high-speed steel rolls without pre-formed oxide film, 15 rolling plans were selected. After the hot rolls of 5 strip steels were rolled in each rolling plan, the rolls were operated at the normal calibration speed of 200m / min. The roll gap was adjusted to 1mm, and the rolling pressure was recorded. A total of 15 rolling pressures were recorded for the 15 rolling plans. The maximum value Fmax = 750 tons and the minimum value Fmin = 560 tons of these 15 rolling pressures were taken. At the same time, the average value Fave = 630 tons of these 15 rolling pressures was calculated.

[0043] 2) Calculate the target range of rolling pressure when operating at the normal calibrated speed of 200m / min and with a roll gap of 1mm. The lower limit of the target range of rolling pressure is F1 = (Fave + Fmin) / 2 = 595 tons, and the upper limit is F2 = (Fmax + Fave) / 2 = 690 tons. The target range of rolling pressure is used to characterize the range of roll thermal crown of the pre-oxidized high-speed steel roll during the rolling hot roll stage.

[0044] 3) Calculate the required cooling water volume A for the pre-oxidized high-speed steel roll according to the following formula (1).

[0045] A = (a1 + a2) / 2 (1),

[0046] In formula (1), a1 is the normal cooling water volume of the high-speed steel roll without pre-coated oxide film during the rolling hot roll stage, i.e., a1 = 1320 m³ / s. 3 / h, where a2 is the minimum roll cooling water volume for high-speed steel rolls without pre-oxidized film during the rolling and hot-rolling stage, generally taken as a2=70% * a1=924 m 3 / h, then A = (1320 + 924) / 2 = 1122 m 3 / h;

[0047] 4) When using pre-oxidized high-speed steel rolls for hot rolling, follow procedure A, i.e., 1122m. 3 / h Configure the cooling water volume of the rolls. After the normal rolling of 5 strip hot rolls is completed, run at the normal calibrated speed of 200m / min and adjust the roll gap to 1mm. Record the rolling pressure f0 at this time as 700 tons. Since 700 tons is not within the range of 595-690 tons, proceed to the next step.

[0048] 5) Since 700 > 690, take a2 = A = 1122 m 3 / h, a1 remains unchanged, and the new roll cooling water volume A2 during hot rolling of the pre-oxidized high-speed steel roll is recalculated according to formula (1) A2=(a1+ A) / 2=(1320+1122) / 2=1221 m 3 / h;

[0049] 6) Repeat step 4), and when rolling with the pre-oxidized high-speed steel rolls on the hot rolls again, follow A2, i.e., 1221 m. 3 / h Configure the roll cooling water volume. After completing the normal rolling of 5 strip steel hot rolls, run at the normal calibrated speed, adjust the roll gap to 1mm, and record the rolling pressure f2 at this time as 630 tons. Since 630 tons is within the range of 595-690 tons, A2 is selected as the roll cooling water volume of 1221 m³ / h for pre-oxidized high-speed steel rolls during hot roll rolling. 3 / h remains unchanged;

[0050] 7) After the pre-oxidized high-speed steel rolls are rolled on hot rolls, the cooling water volume of the rolls during subsequent rolling processes is restored to the initial a1 (1320m) in step 3). 3 / h.

[0051] Obviously, if f2 in step 6) does not fall within the rolling pressure target range F1-F2, then repeat step 5).

[0052] This process is repeated until the required amount of cooling water for the pre-oxidized high-speed steel rolls during hot rolling is determined.

[0053] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the amount of cooling water used in the cooling of a pre-oxidized film high speed steel roll during the rolling of a hot strip, characterized by: The following steps are performed: 1) In the rolling of normal non-preformed oxide film high speed steel rolls, 10-20 rolling plans are selected, 5 blocks of strip are completed in each rolling plan, after the hot rolling rolling gap is adjusted to 1mm, and the rolling pressure at this time is recorded, 10-20 rolling pressures are recorded in total, the maximum value Fmax and the minimum value Fmin of the 10-20 rolling pressures are taken, and the average value Fave of the 10-20 rolling pressures is calculated; 2) The rolling pressure target range at normal calibration speed operation and a rolling gap of 1mm is calculated, the lower limit of the rolling pressure target range F1=(Fave+Fmin) / 2, and the upper limit of the target F2=(Fmax+Fave) / 2, the rolling pressure target range is used to represent the range of the rolling thermal crown of the preformed oxide film high speed steel roll in the hot rolling stage; 3) The required rolling cooling water amount A of the preformed oxide film high speed steel roll is calculated according to the following formula (1), A=(a1+a2) / 2 (1), In formula (1), a1 is the normal rolling cooling water amount of the non-preformed oxide film high speed steel roll in the hot rolling stage, and a2 is the minimum rolling cooling water amount of the non-preformed oxide film high speed steel roll in the hot rolling stage, a2=70%*a1 is taken; 4) The rolling cooling water amount A is configured when the preformed oxide film high speed steel roll is rolled, when 5 blocks of strip are completed in the hot rolling, the rolling gap is adjusted to 1mm, and the rolling pressure f0 at this time is recorded, If f0 falls within the rolling pressure target range F1-F2, A is selected as the rolling cooling water amount of the preformed oxide film high speed steel roll in the hot rolling, and directly goes to step 7); If f0 does not fall within the rolling pressure target range F1-F2, the next step is performed; 5) If f0F1, a1=A, a2 is unchanged, the new rolling cooling water amount A1 of the preformed oxide film high speed steel roll in the hot rolling is recalculated according to formula (1), A1=(A+a2) / 2; If f0>F2, a2=A, a1 is unchanged, the new rolling cooling water amount A2 of the preformed oxide film high speed steel roll in the hot rolling is recalculated according to formula (1), A2=(a1+A) / 2; 6) Step 4) is repeated, and the rolling cooling water amount A1 or A2 is configured when the preformed oxide film high speed steel roll is rolled again, when 5 blocks of strip are completed in the hot rolling, the rolling gap is adjusted to 1mm, and the rolling pressure f1 or f2 at this time is recorded, if f1 or f2 falls within the rolling pressure target range F1-F2, A1 or A2 is selected as the rolling cooling water amount of the preformed oxide film high speed steel roll in the hot rolling, If f1 or f2 does not fall within the rolling pressure target range F1-F2, step 5) is repeated; This is repeated until the rolling cooling water amount of the preformed oxide film high speed steel roll in the hot rolling is selected; 7) After the pre-oxidized film high speed steel roll is finished with the hot roll rolling, the roll cooling water amount of the pre-oxidized film high speed steel roll is restored to the initial a1 in the step 3) when the roll is subsequently rolled.