JPH0729133B2 - Roll grinding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a roll grinding method for imparting a predetermined profile to a roll worn by rolling. More specifically, the present invention is a distribution of the amount of wear of the roll worn by rolling in the cylinder length direction, in other words, the rolling profile without actually measuring the roll profile, and is calculated based on the length of the material to be rolled, etc.
The present invention relates to a roll grinding method in which grinding is performed on the basis of the calculated value to give a predetermined profile to the roll.

(Prior Art) The surface of a roll used for rolling wears as it is used,
Roll profile and surface roughness change. When rolling is performed with the roll profile thus changed, deterioration of the product shape (for example, nonuniform sheet thickness) occurs. Therefore, when the roll profile changes as described above, it is necessary to correct it to a predetermined roll profile by some means.

As one of such means, there has been conventionally known a method of grinding the roll surface into a predetermined profile by using a grinding tool such as a grindstone.

Conventionally, such roll grinding is generally performed by removing the roll from the rolling stand, but with this means, the work efficiency and the productivity are reduced due to the roll removal and the re-installation. I couldn't avoid it.

Therefore, recently, various means for grinding without removing the roll from the rolling stand, that is, an in-line grinding method have been studied and proposed.

The steps of such an in-line grinding method are generally
First, measure the profile of the worn roll, calculate the required grinding amount from the difference from the target value, and based on this calculated value, press a grinding tool such as a grindstone placed around the roll against the roll surface to measure the body length. To move and grind,
Alternatively, it consists of arranging a grindstone over the entire length of the roll in the cylinder length direction and pressing it against the roll surface for grinding. As such a proposal, for example, JP-A-58-16
715, 59-42271, and JP-A-63-267151 are known. Further, JP-A-63-84706 proposes a means for grinding the roll surface by projecting high-pressure water mixed with a polishing agent made of sand iron or the like instead of the grindstone onto the roll surface. There is.

By the way, the accuracy required for grinding the roll is about several μm to several tens of μm. For this purpose, the amount of wear of the roll is measured with high accuracy before grinding, and the grinding is performed accurately based on this measurement value. There is a need to. As a measuring machine that satisfies such requirements, a method of moving a highly sensitive measuring machine such as an operating transformer in the cylinder length direction of the roll for measurement is widely known.

However, the circumference of the mill stand on which this measuring machine is installed is in a bad environment such as high temperature, high humidity, large impact vibration, large amount of dust, etc., and it is easy to cause a decrease in accuracy of the measuring machine and the moving device of the measuring machine. . That is, it has been found that it is difficult to perform precise measurement due to the influence of disturbance factors such as vibration and heat, and there is a problem in the durability of the measuring instrument due to the influence of water vapor and heat.

Therefore, there is a problem that it is difficult to stably maintain a predetermined profile for a long period of time by actually measuring the roll profile.

Therefore, the applicant of the present invention has previously described, in Japanese Patent Laid-Open No. 61-88906, "In the method of grinding a roll worn by rolling into a predetermined profile, the distribution of roll wear amount in the cylinder length direction is set under rolling conditions and a material to be rolled. The roll profile is calculated based on the rolling history including the length and width, the required grinding amount corresponding to the difference between the profile and the predetermined profile is calculated, and the roll is ground based on the calculated value. Roll grinding method characterized by. " In short, this proposal uses the formula to calculate the amount of wear in the cylinder length direction of the roll, that is, the profile of the roll, taking into account the history of the rolled material, the number of rolls, and the amount of heat up due to heat conduction of the rolled material. This is a method of grinding the roll without measuring the profile of the worn roll by calculating the required grinding amount from the difference between the calculated roll profile and a predetermined roll profile.

According to this proposal, it is not necessary to use the high-precision roll profile measuring machine as described above, so that the roll profile can be reliably determined accurately over a long period of time.

(Problems to be Solved by the Invention) By the way, the shape of the roll profile obtained by the method proposed in JP-A-61-88906 is expressed by the following equation (1) calculated based on the idea.

Here, ΔW (i): Roll wear amount at position i (at material rolling position) i: Distance from center of roll cylinder length direction ΔW: Unit [m] α: Wear constant (no unit) where wear constant The meaning of α is a constant for correcting the difference between the predicted wear amount and the actual wear amount when the amount of wear of the roll due to friction between the roll and the rolled material is expressed by the equation (1).

For example, when the actual wear amount is 1.1 times the predicted wear amount when α = 1.0 in equation (1), the next prediction is α
= 1.1.

The wear constant is a constant for correcting the difference between the predicted value and the actual value at a certain ratio, and the wear coefficient is different for each roll material and rolling material or for each combination of two roll materials. It is defined as a coefficient that expresses ease.

P (z): Load distribution in roll barrel direction P (z) unit: [N / m] z: Distance from center of roll cylinder length t ₀ : Lock-on timing t ₁ : Lock-off timing Lock-on, lock-off : Start point and end point of automatic plate thickness control (AGC), which is synonymous with plate biting and slipping out β (k): k of wear coefficient β (k) between roll material and material to be rolled : A symbol that identifies a combination of a certain roll material and a certain rolled material V (t): Roll rotation speed Roll rotation speed: Unit [rpm] n (j): Pass number of the jth rolled material No. D: Work roll Diameter N: number of rolling However, as a result of further studies by the present inventor, in this formula, the amount of wear caused by contact between the work roll and the backup roll, and the contact between the upper and lower work rolls No consideration of wear amount I noticed the door. Therefore, the wear amount (calculated value) of the roll obtained by the formula (1) is different from the actually measured value and cannot be said to be an accurate value. Therefore, the method proposed by JP-A-61-88906 is proposed. It was revealed by the present inventors' subsequent studies that the profile of the roll obtained after grinding the roll was not always accurate.

Here, the object of the present invention, the cylinder length direction distribution of the amount of wear of the roll abraded by rolling, in other words, the rolling conditions without measuring the roll profile, calculated based on the length of the material to be rolled, etc., It is an object of the present invention to provide a roll grinding method in which grinding is performed based on a calculated value and a predetermined profile is accurately given to the roll.

(Means for Solving the Problem) As a result of various studies to solve the above problems, the present inventor caused by friction between the roll and the material to be rolled expressed by the formula (1). In addition to the amount of wear, by adding the amount of wear caused by the friction between the roll and the backup roll and the amount of wear caused by the friction between the upper and lower work rolls, it is possible to solve the above problems. Based on the findings, the present invention was completed.

Here, the gist of the present invention is a roll grinding method in which a roll worn by rolling a steel material or a steel plate is ground while being incorporated into a rolling mill, and a predetermined profile is given to the roll, which is worn. Without measuring the profile of the roll, the amount of wear caused by contacting the roll with a backup roll, and the amount of wear caused by contact between the upper and lower rolls of the worn roll based on rolling conditions A roll grinding method characterized in that a profile is calculated, and a roll is ground based on a required grinding amount obtained from a difference between the calculated profile and the predetermined profile.

(Operation) Hereinafter, the present invention will be described in detail together with operation effects.

Briefly, the present invention is an improved invention of the invention proposed by JP-A-61-88906, and the invention proposed by JP-A-61-88906 considers the calculation of a worn roll profile. Calculation of the roll wear amount in addition to the roll wear amount under the condition not performed, that is, the wear amount caused by the roll to be ground coming into contact with the backup roll, and the wear amount caused by the contact between the upper and lower rolls. And the grinding of the roll is performed according to the amount of roll wear thus calculated.

Therefore, the profile of a worn roll can be
It can be calculated with higher accuracy than the invention proposed by Japanese Patent Laid-Open No. 88906.

First, a method for carrying out the present invention will be described in detail. An example of the configuration for carrying out the present invention is schematically shown in FIG. In the figure, reference numeral 1 is a grinding control device for controlling roll grinding on an in-line. The grinding method and device are not particularly limited. For example, the above-mentioned JP-A-58-1671
No. 5, etc., a method of grinding by pressing a whetstone onto the roll surface, or, as proposed by Japanese Patent Laid-Open No. 63-84706, (high-pressure water + polishing material) is applied to the roll surface. A method of spraying and grinding can be exemplified. That is, any method capable of grinding the roll surface may be used.

Further, in FIG. 1, reference numeral 2 denotes a rolling data collecting device for collecting data on rolling conditions necessary for calculating a profile of a worn roll. The rolling speed and rolling material data (material, rolling oil It is a device that takes in data such as presence or absence and its type) and rolling load. In general,
A calculator controlling the measuring machine can be used instead.

Furthermore, 3 is the grinding result data from the grinding control device 1,
It is a computing device that receives rolling data from the rolling data collection device 2 and performs a computation to output a grinding command to the grinding control device 1. The arithmetic unit 3 calculates a roll profile as described later.

Next, the content of the calculation performed in the above-described calculation device 3 will be described. The grinding logic performed in this arithmetic unit 3 is shown in FIG. Hereinafter, description will be given with reference to FIG.

First, the current roll wear profile is predicted from the rolling data sent from the rolling data collection device 2. At this time, as described above, from the rolling conditions in which the wear amount due to the friction between the roll and the backup roll and the wear amount due to the friction between the rolls are taken into consideration, the predicted value of the current wear profile of the roll is It is calculated. Specifically, the following equation (2) may be used.

Roll wear amount ΔW (i) = ΔW ₁ (i) + ΔR (i) + ΔW ₀ (i) ……
(2) However, the amount of wear at ΔW (i): i (total) ΔW ₁ (i): The amount of wear caused by friction between the roll and the rolled material at position i ΔR (i): i Amount of wear caused by friction between rolls and backup rolls at position ΔW ₀ (i): Amount of wear caused by friction between upper and lower rolls at position i (upper and lower work rolls when rolling a thin plate) If there is no contact between the upper and lower work rolls, the value is 0.) and ΔW ₁ (i) is as described in (1) above. ) Equation.

Further, ΔR (i) is calculated by the following equation (3). That is, However, α ₁ : wear constant The expression (3) is obtained by applying the expression (1) to the roll wear at the non-rolling position of the material during roll kissing.

Definitions of other symbols are the same as in the case of the expression (1).

γ (k): wear coefficient due to material of work roll-backup roll P ₁ (z): load distribution in roll barrel direction during material rolling P ₂ (z): in roll barrel direction during non-rolling (idle) Load distribution t ₀ ′: lock-off timing t ₁ ′: lock-on timing. Further, ΔW ₀ (i) is calculated by the following equation (4). That is, However, ΔW ₀ (i): Amount of wear of roll at position i (non-rolling position) α ₂ : Wear constant δ (k): Wear coefficient due to material of upper and lower work rolls t ₀ ^* : Kiss roll on timing t ₁ ^* : Kiss roll-off timing ΔW ₀ (i) = 0: (rolling position) Other symbols such as P (z) and V (x) have the same definitions as in formula (1), and α ₂ is α, δ. Corresponds to β.

By combining the predicted value ΔW (i) of the roll wear profile thus obtained with the predicted value of the roll profile obtained by grinding, the predicted value of the roll profile is calculated every moment.

Here, the predicted value of the profile obtained from the grinding results refers to the grinding conditions (for example, when grinding is performed with high-pressure water containing polishing / cleaning material, the mixing amount of polishing / cleaning material, pressure and flow rate of high-pressure water). , The amount of grinding, etc.) and the amount of grinding independent of the amount of wear is predicted and obtained. The roll profile can be predicted for the first time by predicting the wear amount and the grinding amount and adding them.

Next, in FIG. 1, the difference between the predicted value of the roll profile thus obtained and the predetermined target profile is obtained by the arithmetic unit 3, and the grinding required for each part in the roll cylinder length direction is performed. Calculate and obtain the amount.

Then, the value of the required grinding amount may be output to the grinding control device 2 to give a desired grinding amount to the roll.

Thus, according to the present invention, the distribution of the roll wear amount in the cylinder length direction, in other words, the rolling profile without actually measuring the roll profile is calculated based on the length, etc. of the material to be rolled, and based on the calculated value. It is possible to provide a roll grinding method in which grinding is performed to accurately give a predetermined profile to the roll.

Further, the present invention will be described in detail with reference to examples, but this is merely an example of the present invention, and the present invention is not limited thereto.

(Example 1) Thick plate rolling mill (maximum load: 8700 tons, roll body length: 4600 m)
An example applied to m) is shown using FIG. 3 and FIG.

FIG. 3 shows a roll ground by applying the roll grinding method according to the present invention, and FIG.
9 is an enlarged graph showing the predicted value and the actual value of the wear amount in the vicinity of the contact portion of each of the upper and lower rolls of the roll that has been ground by applying the method proposed in Japanese Patent Laid-Open No. 88906.

The measurement of the results shown in FIGS. 3 and 4 is the result after continuous rolling for 15 hours and 15 minutes, the number of rolled slabs was 325, and the total rolling tonnage was 3418 ton. It was In addition, the roll diameter and the amount of each roll are collectively shown in Table 1 for each of the upper roll and the lower roll.

Further, the roll grinding was performed by moving the roll stone in the longitudinal direction of the roll while pressing the grindstone against the roll surface.

In the embodiment shown in FIG. 3, the difference between the calculated roll wear amount and the actually measured value is 0.04 mm at the maximum, which is an extremely excellent value.

On the other hand, in the comparative example according to the method disclosed in Japanese Patent Laid-Open No. 61-88906 shown in FIG. 4, the difference is 0.1 mm at maximum, and according to the present invention, the roll wear is extremely highly accurate. It is clear that the quantity could be predicted.

(Example 2) An example in which the present invention is applied to a work roll used in a thick plate rolling mill as in Example 1 will be described.

For the same rolls used in Example 1,
Rolls were ground using the roll grinding method according to the present invention. For the grinding of the roll, as described in JP-A-63-84706, a polishing agent (sand iron) and high-pressure water (500 kg) were mixed at the position inside the nozzle after the high-pressure water was sprayed. High pressure water mixed with abrasives, 4.5 kg / from spray nozzle
Grinding was performed by spraying at four places on the upper and lower work rolls at a flow rate of minutes. However, the grinding time was 14 hours and 20 minutes. The number of rolled slabs is 895 and the total rolling tonnage is 9124.
It was a ton.

The roll diameter and the amount of crown are collectively shown in Table 2.

The results are shown in FIGS. 5 and 6.

FIG. 5 shows the result when roll grinding was performed by applying the method according to the present invention, and FIG. 6 shows roll grinding by applying the method proposed by Japanese Patent Laid-Open No. 63-84706. The result when it went is shown.

As is clear from FIGS. 5 and 6, the maximum error according to the present invention is 0.08 mm, while the maximum error according to the comparative example is 0.33 mm.

Therefore, roll grinding can be performed with high accuracy according to the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to accurately predict a roll profile and accurately give a predetermined profile even though it is a method of performing in-line grinding. . Therefore, it is possible to extend as much as possible the cycle in which it becomes necessary to finally perform the roll exchange. Further, the operating rate of the rolling mill can be improved.

Further, it is possible to stably manufacture a product which is a high-quality material to be rolled with a high amount of plate crown and a high degree of flatness.

The significance of the present invention having such effects is extremely remarkable.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view schematically showing an example of a configuration for carrying out the present invention; FIG. 2 is a schematic explanatory view showing a grinding logic performed in the arithmetic unit 3 in FIG. FIG. 4 and FIG. 4 are graphs showing the respective results of the present invention example and comparative example in Example 1; and FIGS. 5 and 6 are the present invention example and comparative example in Example 2. It is a graph which shows each result. 1: Grinding control device, 2: Rolling data collection device, 3: Computing device

Claims (1)

[Claims] 1. A roll grinding method, wherein a roll worn by rolling a steel material or a steel plate is ground while being installed in a rolling mill to give a predetermined profile to the roll.
Without measuring the profile of the worn roll,
The amount of wear caused by the roll contacting a backup roll, and the profile of the worn roll is calculated based on rolling conditions including the amount of wear caused by contact between the upper and lower rolls, and the calculated profile A roll grinding method characterized in that a roll is ground based on a required grinding amount obtained from a difference from the predetermined profile.