JP2002001409A - Method and apparatus for setting up rolling speed in universal rolling of section having flange and web - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set up a rolling speed of a universal rolling mill with high accuracy, so as to prevent damage to equipment, and miss-rolling, and improve manufacturing efficiency. SOLUTION: When a universal rolling for a section having a flange and a web is performed, a necessary torque for rolling is estimated and the rolling speed in the universal rolling is determined or amended in compliance with the necessary torque through functions coming from parameters based on a cross sectional area and dimension of the flange, deformation resistance of the flange, thickness draft of the flange, and the difference of thickness drafts of the flange and web.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to universal rolling of a profile having a flange and a web, and more particularly to a method and an apparatus for setting a rolling speed for determining or correcting the rolling speed.

[0002]

2. Description of the Related Art As shown in FIG. 1 or FIG. 2, a rolling mill for a section steel having a flange and a web, such as an H-section steel, includes a breakdown rolling mill 10 and a coarse universal rolling mill (FIG.
a and 20b, FIG. 2 is one of 20), an edging rolling mill 30, and a finishing universal rolling mill 40, and is usually composed of a material such as a slab, a bloom or a beam blank. ) Are rolled in order to produce a shaped steel having a predetermined cross-sectional dimension.

[0003] Taking the method of rolling an H-section steel as an example, the breakdown rolling mill 10 arranged in the above-mentioned equipment is provided with upper and lower rolls provided with a plurality of open-type or closed-type dies along a roll cylinder. In this case, a rough rolling slab of H-section steel is rolled.

In a rough universal rolling mill 20 having a pair of upper and lower horizontal rolls and a pair of right and left vertical rolls, the rolling of the rough steel slab obtained by breakdown rolling is further advanced, as shown in FIG. In addition, the web of the rolling material 8 is pressed down in the thickness direction by the roll gap formed by the pair of upper and lower horizontal rolls 22 and formed by the left and right vertical rolls 24 and the side surfaces of the upper and lower horizontal rolls 22. The four flanges are pressed down in the thickness direction by the four roll gaps.

[0005] As shown in FIG. 4, the flange width is reduced to a predetermined size by an edger roll 32 of an edging mill 30 used in combination with the rough universal mill 20.

[0006] The above rough rolling is repeated a plurality of times until the material has a predetermined cross-sectional dimension. Then, as shown in FIG. 5, a finishing universal rolling mill 40 having upper and lower horizontal rolls 42 and vertical rolls 44 is used. In addition to reducing the thickness of the flange and web, the finished product is finished to the final product dimensions by finishing universal rolling that raises the angle of the flange.

In the past, the operator manually set the rolling speed for such universal rolling, but in recent years, automation has been promoted from the viewpoint of improving productivity and reducing the load on the operator. It has become.

When setting the rolling speed automatically, it is necessary to take care that the load acting on the drive system of the rolling mill, such as a motor for rotating the rolling roll (hereinafter referred to as a mill motor) and a spindle, does not become excessive. . If the load on the drive system (especially the load on the mill motor) is excessive, there is a risk that so-called "misroll" occurs, in which rolling is abandoned and the raw material does not become a product, or in the worst case, equipment damage.

Factors that affect the load on the drive system of a rolling mill include "rolling torque" that reduces the thickness of the material and plastically deforms it. The rolling speed and acceleration of the material also affect the load on the drive system. For this reason, when the rolling torque increases, it is necessary to set the rolling speed and the acceleration to a small value. Therefore, it is important to predict the rolling torque and set the rolling speed and acceleration.

[0010] As a formula for predicting the rolling torque of an H-section steel, there is a document pp. 137-140 (hereinafter referred to as Reference 1) in the Spring Meeting of the Japan Plastic Working Society in 1972. This represents the rolling torque G as in equation (1).

G = 2Ph · φ · Ldw + 2Pv · φ ′ · (Rh / Rv) · Ldf ‥‥ (1) Ph: Horizontal roll load Pv: Vertical roll load Ldw: Contact arc length between web and roll Ldf: Flange Contact arc length with roll Rh: Horizontal roll radius Rv: Vertical roll radius φ: Plate rolling torque arm coefficient φ ': Vertical roll torque arm coefficient

Conventionally, the actual rolling torque and the current value of the mill motor are investigated based on the above-mentioned method and past rolling results, and the rolling pass schedule and the rolling speed of each rolling pass are previously determined so that these values do not become excessive. It was common to set and roll.

Another factor that affects the load on the drive system of a rolling mill is the unbalance of the rolling speed in a plurality of stands (the effect of the tension between stands), which is disclosed in Japanese Patent Application Laid-Open No. 3-146210. (JP-A-3-146
No. 209 gazette) discloses the following technology.

When rolling an H-section steel with a rough universal rolling mill (original stand, also simply described as an edger stand) and a finishing universal rolling mill arranged in tandem, the material bites into the rough universal rolling mill. The rolling torque is calculated on the basis of the load and rolling reaction force at the time of loading, and the deformation resistance ratio of the flange in finish universal rolling is calculated from the material dimensions and temperature.
Based on the two calculation results, a torque deviation at which the tension acting on the material between the stands becomes a predetermined value is calculated, and the rotation speed of the roll of the finishing universal rolling mill is corrected based on the calculation of the torque deviation.

[0015]

However, the technique disclosed in Japanese Unexamined Patent Publication No. 3-146210 is a method for controlling the tension in tandem rolling of an H-section steel. The actual rolling torque is calculated from the actual rolling load, and the rolling speed is corrected based on the actual rolling torque so that the inter-stand tension becomes a target value. That is, according to the technique disclosed in Japanese Patent Application Laid-Open No. 3-146210, it is not possible to predict the rolling torque before rolling and set the rolling speed and acceleration based on the predicted rolling torque.

On the other hand, Document 1 discloses a method of predicting a rolling torque by multiplying a product of a contact arc length between a material and a roll and a rolling load by a torque arm coefficient, and is often used in the case of sheet rolling. There is a way. However, particularly in the rolling of a section having a flange and a web, such as an H-section steel, the torque arm coefficient estimation error often increases due to the influence of the interaction between the flange and the web. or,
It is necessary to predict the rolling load in order to predict the rolling torque, but the prediction error of the rolling load directly leads to the prediction error of the rolling torque. That is, the error of the torque arm coefficient and the prediction error of the rolling load overlap, and the rolling torque cannot be accurately predicted over a wide range of rolling conditions.

In the method of examining the actual rolling torque and the like from the past rolling results and setting the rolling speed in advance, not only when the rolling pass schedule is changed, but also when the rolling operation conditions are changed minutely. Had a problem that they could not cope.

An object of the present invention is to solve these problems and to provide a method capable of accurately setting the reference position of each roll.

[0019]

SUMMARY OF THE INVENTION According to the present invention, in universal rolling a profile having a flange, the sectional area of the flange, the deformation resistance of the flange, the thickness reduction rate of the flange, the sectional area of the web, and the deformation of the web are provided. Predict the torque required for rolling from a function that uses the difference between the resistance, the thickness reduction of the web, and the thickness reduction of the flange and web as parameters, and determine or correct the rolling speed in universal rolling according to the required torque. Thus, the above-mentioned problem has been solved.

Further, when estimating the torque required for rolling,
The product of the cross-sectional area size of the flange and the deformation resistance of the flange, the product of the cross-sectional area size of the web and the deformation resistance of the web, and the difference between the thickness reduction rate of the flange and the web and the thickness reduction rate of the flange and the web are parameters. The torque required for rolling is predicted from the product of the above function and the following function.

The present invention is also an apparatus for setting a rolling speed of a universal rolling mill for rolling a profile having a flange and a web, comprising: a motor for rotating a horizontal roll of the universal rolling mill; And a table roller that conveys the profile to be rolled on each of the entrance and exit sides of the universal rolling mill, and the flange of the profile, deformation resistance of each web, cross-sectional area,
From the thickness reduction rate condition, a computing device that calculates the rolling torque, and a command device that sets or corrects the rotation speed of the motor and the transport speed of the table roller based on the calculation result of the computing device, This problem has been solved by determining or correcting the rolling speed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A method for predicting a rolling torque in universal rolling according to the present invention will be described using an H-section steel as an example.

First, according to the method described in Reference 1,
The rolling torque was predicted and its accuracy was investigated. The result is shown in FIG. In the method of Document 1, it is necessary to predict the rolling load, but the prediction of the rolling load also followed the method described in Document 1. For actual machines that roll H-beams of various and various dimensions under various and various conditions, the variation in the predicted rolling torque relative to the measured rolling torque is very large. It was also found that the prediction error of the rolling load was also superimposed.

In conclusion, it was judged that it was dangerous to predict the rolling torque and set the rolling speed by the method described in Document 1.

Therefore, the present inventors have studied a method of directly estimating the rolling torque from a wide variety of material dimensions and rolling conditions without estimating the rolling load.

For this purpose, first, the effect of the dimensions and shape of the material on the rolling torque and the effect of the thickness reduction rate conditions on the rolling torque were examined by a model rolling experiment of an H-section steel.

As a result, it was first confirmed that when a material having the same size and shape was rolled under the same thickness reduction ratio, the rolling torque was approximately proportional to the deformation resistance K of the material. Here, as in the prior art, assuming that K depends on the function f determined by the material temperature T, the chemical component C, and Mn ‥‥, and the strain ε and the strain rate εd, as shown in Expression (2). did .

K = f (T, C, Mn, ‥‥) · ε ⁿ · εd ^m ‥‥ (2) where n and m are coefficients.

Next, when the deformation resistance of the material is the same and the thickness reduction rate of the flange and the thickness reduction rate of the web are almost the same, respectively, the rolling torque is calculated as shown in FIG. It was found that it was approximately proportional to the area dimension. Although the cross-sectional area dimensions used in FIG. 7 are dimensions before rolling, almost the same results can be obtained with dimensions after rolling.

Further, when rolling is performed under various thickness reduction conditions for the case where the deformation resistance of the material and the dimensions of the material are the same, the rolling torque increases when the difference between the thickness reduction ratio of the flange and the web is constant. , And that the rolling torque increases and decreases depending on the difference in the thickness reduction between the flange and the web (FIG. 9).

Here, the thickness reduction ratio r is defined as a log reduction ratio as shown in equation (3), where h0 is the thickness before rolling and h1 is the thickness after rolling. There is no big difference.

R = ln (h0 / h1) ‥‥ (3) (ln represents natural logarithm)

In addition to these results, various studies such as a theoretical analysis and a survey of actual rolling performance on an actual machine were further advanced, and as a result, a parameter P shown in equation (4) was devised.

P = Kw · Aw · rw + Kf · Af · rf + α · (Kw · Aw + Kf · Af) · | rf−rw−β | (4) where K is the deformation resistance, A is the cross-sectional area, and r is Rolling reduction, α,
β represents a coefficient, and subscripts w and f represent a web and a flange, respectively.

FIG. 10 shows the relationship between the parameter P and the rolling torque T. It is understood that the rolling torque can be accurately represented by the parameter P of the present invention.

From this result, the relationship between the parameter P and the rolling torque T can be expressed as, for example, Expression (5).

T = Rh · [a · P + b · [1-exp (−c · P)]]] (5) where Rh is a horizontal roll radius, and a, b, and c are coefficients.

FIG. 11 shows the relationship between the rolling torque predicted by using the equation (5) and the actual rolling torque. It can be seen that the rolling torque can be accurately predicted by this method.

Next, a method for setting the rolling speed and the acceleration from the predicted rolling torque will be described. Although the rate of change of the speed with time is acceleration, in the present application, the speed including the acceleration is referred to as the rolling speed.

As shown in FIG. 12, the rolling speed pattern usually includes a base speed range before biting, an acceleration range after biting, a steady speed range, and a deceleration range at the end of rolling. Before biting, the material is conveyed by a table roller, and the rotation speed of the table roller is set in accordance with the rotation speed of the rolling roll.

The upper limit of acceleration in the acceleration region and the upper limit of speed in the steady region are determined by the specifications of drive system equipment such as a mill motor. Therefore, several types of rolling speed patterns having different tops (speeds in the steady speed range) are prepared in advance within a range not exceeding the upper limit of the specifications of the drive system equipment. In this case, the acceleration / deceleration rate can be determined from the equipment specifications so that the acceleration / deceleration time is the shortest.

Next, the rolling torque is predicted by equation (5).

Then, a suitable speed pattern is selected based on the predicted rolling torque. Specifically, for example, when the predicted rolling torque shown above is large, a pattern with a small acceleration or steady rolling speed is selected, and when the predicted rolling torque is small, a pattern with a large acceleration or steady rolling speed is selected. I do.

Finally, the acceleration / deceleration rate and the top speed are determined based on the selected speed pattern.

In addition, since the load on the drive system such as a mill motor is determined by the rolling torque and the rolling speed / acceleration, the load on the drive system is determined as a function of the rolling torque and the speed / acceleration. The speed and acceleration can be determined so as not to exceed the equipment specifications.

When correcting the rolling speed, rolling is first performed based on the set speed pattern. At this time, it is monitored whether the current value flowing through the mill motor exceeds a predetermined ratio (for example, 90%) of the allowable value.

If it does not exceed, the next pass continues rolling as set. If it exceeds, the speed pattern of the next pass can be changed to a speed pattern with a smaller one-step load.

Next, an apparatus suitable for carrying out the present invention will be described with reference to the drawings. In FIG. 13, 8
Is a roll to be rolled; 42 is a horizontal roll of a universal rolling mill (only a horizontal roll is driven in a universal rolling mill, and a vertical roll is usually not driven); 46 is a mill motor (M) for driving the horizontal roll 42; 43 is a transmission unit for transmitting the rotation of the mill motor 46 to the roll 42;
Reference numerals a and 41b denote table rollers for transporting the material on the entrance side and the exit side of the universal rolling mill, respectively. Reference numeral 48 denotes an arithmetic unit, which predicts a rolling torque according to the method of the present invention from the temperature of the material measured by the measuring device 50, the actual dimensions before rolling, the target dimensions in the pass, and the like. A suitable rolling speed pattern is selected from the rolling torque. Reference numeral 52 denotes a command device for giving a rotation speed command to the mill motor 46 and the table rollers 41a and 41b based on the speed pattern determined by the arithmetic device 48.
During rolling, the current value i of the mill motor 46 is monitored. If the current value exceeds, for example, 90% of the allowable value, the speed pattern of the next pass is lowered by one rank.

Instead of measuring the temperature and dimensions with the measuring device 50, a mathematical model for calculating the material temperature and material dimensions is introduced into the arithmetic unit 48, and the temperature of the material and the dimensions before rolling are calculated. Then, the rolling torque may be calculated using these temperatures and dimensions.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a mill having a mill arrangement shown in FIG.
The rolling speed setting device shown in 3 is incorporated in the coarse universal rolling mill, and the setting of the rolling speed in the coarse universal rolling is performed.
This was done automatically according to the invention. A mathematical model for calculating the material temperature and dimensions of each pass in the rough universal rolling was introduced into the arithmetic unit 48, and the rolling torque was predicted before the start of the rough universal rolling. Then, according to the predicted rolling torque, an appropriate speed pattern was selected from several types of rolling speed patterns prepared in advance (Compliance Example 1). For comparison, the rolling torque is predicted in the same manner as in the applicable example by the method shown in Document 1, and the rolling speed is set according to the predicted rolling torque (Comparative Example 1). Was set in advance, and the case where the rolling speed was set in accordance with this (Comparative Example 2) was also investigated.

In each case, 30 materials each having five types of product dimensions were prepared and rolled. FIG. 14 shows the rolling state at this time. In the case of the adaptation example 1, the rolling could be smoothly performed without the load on the drive system becoming excessive (without occurrence of misrolling) for all the product dimensions. On the other hand, in Comparative Example 1, the product size B
(Web height 400mm, flange width 400mm, web thickness 13mm, flange thickness 21mm, steel type SM490
In A), five misrolls occurred due to an excessive load on the drive system. In Comparative Example 2, three misrolls similarly occurred at the product size C. Also, when comparing the times required for rolling, it was found that Adaptation Example 1 was short (in Adaptation Example 1, the rolling speed was properly set), and that rolling could be performed efficiently.

For steel type B, in order to show the effect of the present invention in more detail, the ratio of the maximum load acting on the drive system for each pass to the upper limit of the equipment specification for each representative example of the adaptation example 1, the comparative examples 1 and 2 ( %) And the ratio (%) of the rolling speed in the steady region to the upper limit of the equipment specifications are shown in FIG.

FIG. 15 shows that, in accordance with the present invention, there was no problem that the load acting on the drive system became excessive, and the rolling was properly performed. The time required for rough universal rolling was 166 seconds. On the other hand, in Comparative Example 1, since the rolling torque in the fourth pass was predicted to be considerably smaller than the actual rolling speed, the rolling speed was set too high, and the load acting on the drive system became excessive (over 100%), and the rotation of the rolls was increased. Stopped, resulting in a misroll. In Comparative Example 2,
The load on the fourth pass is heavy, very dangerous, and 5
The setting of the speed of the pass, the 7th pass, etc. was too slow, and the time required for the rough universal rolling was 185 seconds, which was longer than that of the first example.

In this embodiment, the rolling of the H-section steel by the equipment row of FIG. 2 has been described. However, the case of using the equipment example of FIG. 1 and the case of manufacturing the I-section steel and the channel steel by universal rolling. It has been confirmed that the same effect can be obtained for In the present embodiment, the rolling speed is selected and determined from the speed pattern based on the prediction of the rolling torque.However, the same applies to the case where the preset rolling reference speed is corrected according to the predicted rolling torque. Needless to say, the effect of (1) is obtained.

[0055]

According to the present invention, the rolling speed of the universal rolling mill can be automatically set without fear of equipment breakage or misrolling. Further, since an optimum rolling speed can be set for each rolling pass, production efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a rolling equipment arrangement of a section steel having a flange and a web.

FIG. 2 is a schematic view showing another example.

FIG. 3 is a schematic diagram showing reduction of an H-section steel in rough universal rolling.

FIG. 4 is a schematic view showing reduction of an H-section steel in edging rolling.

FIG. 5 is a schematic view showing reduction of an H-section steel in finish universal rolling.

FIG. 6 is a diagram comparing a measured rolling torque with a predicted rolling torque according to a conventional torque prediction formula.

FIG. 7 is a diagram showing a relationship between a cross-sectional area of a rolling material and a rolling torque.

FIG. 8 is a diagram showing a relationship between an average thickness reduction rate of a flange web of a rolled material and a rolling torque.

FIG. 9 is a diagram showing the relationship between the difference in thickness reduction between the flange of the rolled material and the web and the rolling torque.

FIG. 10 is a diagram showing a relationship between a parameter P and a rolling torque of the present invention.

FIG. 11 is a diagram comparing a measured rolling torque with a rolling torque predicted according to the present invention.

FIG. 12 is a diagram showing an example of an acceleration / deceleration pattern of a rolling speed in universal rolling.

FIG. 13 is a schematic diagram showing a configuration of a rolling speed setting device suitable for use in carrying out the present invention.

FIG. 14 is a table showing a comparison between rolling conditions of an applicable example of the present invention and a comparative example.

FIG. 15 is a chart comparing and comparing the upper limit of the equipment specification of the maximum load and the ratio of the rolling speed in the steady region to the upper limit of the equipment specification of the representative material.

[Explanation of symbols]

 8 Rolling material 10 Breakdown rolling mill 20, 20a, 20b Rough universal rolling mill 22, 42 Horizontal roll 24, 44 Vertical roll 30 Edging rolling mill 32 Edger roll 40 Finishing universal rolling mill 41a 41b ... Table roller 43 ... Transmission unit 46 ... Mill motor 48 ... Computing device 50 ... Command device 52 ... Measuring device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyasu Shigemori 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. Chome (without address) F-term (reference) at Kawasaki Steel Corporation Mizushima Works 4E002 AC03 BA04 BB01 BB05 BC02 BC03 BC05 CB08 4E024 AA09 BB01 BB02 BB03 BB06 CC07 DD16 EE02 GG07

Claims (4)

[Claims] 1. In performing universal rolling of a profile having a flange and a web, a cross-sectional area dimension of the flange, a deformation resistance of the flange, a thickness reduction ratio of the flange, a cross-sectional area dimension of the web, a deformation resistance of the web, and a thickness of the web. From the function using the difference between the reduction ratio and the thickness reduction ratio of the flange and web as parameters, the torque required for rolling is predicted, and the rolling speed in universal rolling is determined or corrected according to the required torque. How to set the rolling speed to be performed. 2. The product of the cross-sectional area dimension of the flange and the deformation resistance of the flange, the product of the cross-sectional area dimension of the web and the deformation resistance of the web, the thickness reduction rate of the flange and the web, and the thickness reduction of the flange and the web. The rolling speed setting method according to claim 1, wherein a torque required for rolling is predicted from a product of a function having a difference between the rates as a parameter. 3. A device for setting a rolling speed of a universal rolling mill for rolling a profile having a flange and a web, comprising: a motor for rotating a horizontal roll of the universal rolling mill; A transmitting unit for transmitting, a table roller for transporting the profile to be rolled on the entrance side and the exit side of the universal rolling mill; and a deformation resistance, a cross-sectional area, and a thickness reduction ratio of the flange and the web of the profile, and the rolling. 3. The method according to claim 1, further comprising: a calculation device that calculates a torque; and a command device that sets or corrects a rotation speed of the motor and a conveyance speed of the table roller based on a calculation result of the calculation device. 4. A rolling speed setting device for a universal rolling mill, wherein the rolling speed is determined or corrected by the method. 4. The product of the cross-sectional area of the flange and the deformation resistance of the flange, the product of the cross-sectional area of the web and the deformation resistance of the web, the thickness reduction ratio of the flange and the web, and the thickness reduction of the flange and the web. A method for predicting a rolling torque, comprising predicting a torque required for rolling from a product of a function having a difference in rate as a parameter.