JPH09253717A - Method for rolling bar steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling method of bar steel by which the bar steel is rolled with high dimensional accuracy. SOLUTION: In the rolling method, is rolling load is measured at the time of rolling a rolled stock 1 with a universal mill 11 and the succeeding rolled stock 1 is rolled by correcting roll gaps based on the measured rolling load. In such a case, the inlet-side temp., inlet-side thickness and outlet-side thickness of the rolled stock and the rolling load of the vertical rolls 12, or the horizontal rolls 13 are taken as the variable factor of the rolling load, the sum of terms obtd. by that the variation amount of each variable factor is multiplied by respective influence coefficients is taken as a rolling load variation amount model equation, rolling load is estimated by determining the inlet-side temp. of the rolled stock 1 from the the measured inlet-side thickness, measured rolling load of the the rolled stock 1 and the rolling load variation amount model equation, and the roll gaps of the vertical rolls 12 and horizontal rolls 13 are corrected based on the estimated rolling load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling H-shaped steel, I-shaped steel, rails and other strip steels, and more particularly to a method for setting up a roll gap.

[0002]

2. Description of the Related Art Universal rolling is widely used for rolling H-shaped steel and other bar steel. In universal rolling,
By adjusting the roll gap between the horizontal roll and the vertical roll, various types of products can be manufactured. In order to improve the dimensional accuracy of the product, it is necessary to set the roll gap with high accuracy in accordance with changes in rolling conditions.

The rolling control method for rolled material disclosed in Japanese Examined Patent Publication No. 5-73483 obtains the actual value of the deformation resistance of the preceding rolled material from the results of the reduction amount and rolling load of each pass of the preceding rolled material. The rolling schedule is corrected according to the obtained deformation resistance. This technique attempts to reduce variations in product dimensions by setting roll gaps based on predicted rolling loads.

[0004]

[Patent Document 1] Japanese Patent Publication No. 5-734
The rolling control method for rolled material disclosed in Japanese Patent No. 83 determines the variation amount of the deformation resistance based only on the variation amount of the rolling load from the set value. This thickness control method has a simple calculation formula, but when the temperature or size of the rolled material varies between rolled materials, the error of the obtained deformation resistance is large. For this reason, there is a problem that the rolling load prediction error is large, and the roll gap setting accuracy, and consequently the product dimensional accuracy, is low.

The present invention is intended to provide a method for rolling a steel strip which is capable of rolling a steel strip with high dimensional accuracy.

[0006]

A method for rolling a strip of steel according to the present invention measures a rolling load when rolling a rolled material by a universal rolling mill, corrects a roll gap based on the measured rolling load, and performs subsequent rolling. In the rolling method of the strip steel for rolling the material, the inlet side temperature of the rolled material, the inlet side thickness, the outlet side thickness, and the rolling load of the vertical roll or the horizontal roll as the variation factors of the rolling load, the variation amount of each variation factor, respectively. Rolling load fluctuation amount model formula is the sum of the terms multiplied by the influence coefficient of the rolling material, and the measured inlet side thickness of the rolled material and the measured rolling load, and the rolling load inlet side temperature from the rolling load fluctuation amount model equation are used to determine the rolling load. And the roll gap of the vertical roll and the horizontal roll is corrected based on the estimated rolling load.

Further, in the method for rolling a strip of steel according to the present invention, the rolling load is measured when rolling the rolled material by the universal rolling mill, the roll gap is corrected based on the measured rolling load, and the succeeding rolled material is rolled. The method of rolling strip steel consists of the following steps. On the entry side of the universal rolling mill, measure the thickness of the web and flange of the rolled material respectively.Measure the horizontal roll rolling load and vertical roll rolling load for the thickness-measured portion. Determine the amount of variation in the inlet thickness with respect to the initial setting inlet thickness based on the side thickness and the amount of variation in the rolling load with respect to the initial setting rolling load based on the measured rolling load.Inlet temperature of the rolled material, inlet thickness, outlet thickness, And the rolling load of vertical roll or horizontal roll is used as the fluctuation factor of the rolling load, and the sum of the terms obtained by multiplying the fluctuation amount of each fluctuation factor by each influence coefficient is used as the rolling load fluctuation amount model formula. Entry-side thickness and rolling load, and rolling-load fluctuation amount Obtaining the horizontal roll rolling load and vertical roll rolling load from the rolled material inlet side thickness, the rolled material inlet side temperature obtained in the step, and the target outlet side thickness of the rolled material Horizontal roll rolling load obtained in the step and vertical Determine the roll gap of the horizontal roll and the vertical roll by the gauge meter method based on the roll rolling load. Correct the roll gap of the horizontal roll and the vertical roll to the roll gap obtained in the step.

The above steps and are carried out when rolling the first rolled material by the universal rolling mill in which the roll gap is already initialized. The initial roll gap is determined by the gauge meter formula based on the actual or theoretically determined rolling load and the target delivery side thickness. The second and subsequent rolled materials are rolled with the roll gap corrected in the procedure from step to.

The thickness measurement position along the longitudinal direction of the rolled material is set at a fixed position. The center position in the longitudinal direction shows an average thickness in the longitudinal direction, and is suitable as a thickness measurement position.

The rolling load variation model equation used in the above step is obtained from the rolling load model equation. In the rolling load model formula, the deformation resistance, the entrance side thickness, the exit side thickness, and the rolling load of the horizontal roll for the vertical roll and the vertical roll for the horizontal roll are used as variables. The influence coefficient of each variation factor is a partial differential coefficient of the variation factor of the rolling load model formula. Further, since the deformation resistance is obtained by an empirical formula in which the temperature is a variable, the rolling load fluctuation amount model formula includes the temperature of the rolled material as a variable, not the deformation resistance. The rolling load of the vertical roll is influenced by the rolling load of the horizontal roll, and the rolling load of the horizontal roll is influenced by the rolling load of the vertical roll. In general, since the rolling load of the horizontal roll has a small effect on the rolling load of the vertical roll, even if this is ignored, the estimation error of the rolling load of the vertical roll is small. The present invention can also be applied to reverse rolling.

In the present invention, the rolling load fluctuation amount is determined in consideration of the fluctuations of the inlet side temperature of the rolled material, the fluctuations of the inlet side thickness, the fluctuations of the outlet side thickness, and the fluctuations of the rolling load of the vertical or horizontal rolls. Therefore, the rolling load can be predicted with high accuracy, and the accuracy of setting the roll gap can be improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described by taking as an example the case where the bar steel is an H-shaped steel. FIG. 1 is a configuration diagram of a universal rolling mill embodying the present invention.

Before the rolling of the H-section steel 1 is started, the roll gaps S _F and S _W between the vertical rolls 12 and the horizontal rolls 13 are initialized by a gauge meter type. The gauge meter formula is as follows.

[Equation 1] Here, h is the target thickness on the delivery side of the rolling mill, P is the rolling load,
K is the mill stiffness. Further, the subscript F indicates the flange 2 of the H-shaped steel 1, and the subscript W indicates the web 4. The rolling loads P _F and P _W are actual or theoretically the mill rigidity K is a function of the rolling load P, and is obtained in advance by experiments. The flange 2 is pressed down by the vertical roll 12, and the web 4 is pressed down by the horizontal roll 13.
_An explanation will be given assuming that _F = P _V and P _W = P _H.

In the universal rolling mill 11 in which the roll gaps S _F and S _W are preset as described above, the first
Roll the book. At this time, the thickness-measuring devices (X-ray thickness gauges) 15 and 16 arranged on the entrance side of the universal rolling mill 11 measure the thicknesses of the flange 2 and the web 4 on the rolling mill entrance side, respectively. Further, the rolling load is measured by the load cells 18 and 19 for the portion where the entrance side thickness is measured. The measurement results of the entrance side thickness and the rolling load are output to the arithmetic unit 21. The calculation device 21 performs the following calculation based on these measurement results.

From the inlet thickness H _FA , H _{WA The} inlet thickness variation Δ
H _F and ΔH _W are calculated by the following equations.

[Equation 2]

From the measured rolling loads P _VA and P _HA , the rolling load fluctuation amounts ΔP _V and ΔP _H are calculated by the equation (3).

(Equation 3)

Further, the outgoing side thicknesses h _FE and h _WE are obtained from the measured rolling loads P _VA and P _HA and the gauge meter formula.

(Equation 4)

Therefore, the outgoing side thickness variation amount Δh _F , Δh
_W is

(Equation 5) Becomes

Next, the inlet side thickness variation amount Δ obtained from the measured inlet side thicknesses H _FA and H _WA and the measured rolling loads P _VA and P _HA.
The temperatures T _FE and T _WE of the rolled material are obtained from H _F , ΔH _W and the rolling load fluctuation amounts ΔP _V and ΔP _H. Rolling load P _V, P _H
Is represented by the following rolling load model formula.

(Equation 6) The following equations (6. 1) and (6. 2) show specific examples of rolling load model equations.

(Equation 7)

(Equation 8) It should be noted that the deformation resistance k in the equations (6.1) and (6.2)
(T _F ), k (T _W ) is Misaka's formula (“Plasticity and processing” vol.
9 (1968), 127), where T represents temperature and C represents carbon content. Further, the rolling load fluctuation amount is as follows from the equation (6).

[Equation 9]

Further, according to the above equation (7), the rolling load fluctuation amounts ΔP _V and ΔP _H are

(Equation 10) It is expressed as Equation (8) is

[Equation 11] Or,

(Equation 12) Is rewritten as From equation (10), the temperature variation Δ
T _F and ΔT _W are obtained from the following equation (11).

(Equation 13)

Using the above results, the roll gap is corrected and the second and subsequent rolled materials are rolled as follows. From the inlet side thickness variations ΔH _F and ΔH _W , the inlet side thicknesses H _FE and H
_WE is as follows.

[Equation 14] Moreover, the temperatures T _FE and T _WE of the rolled material are

(Equation 15) Becomes The deformation resistance can be obtained from the temperature of the rolled material. To obtain the deformation resistance, Misaka's equation in the above equations (6. 1) and (6. 2) is used.

The obtained deformation resistance k, the entrance side thickness H _FE ,
The vertical roll rolling load P _VE and the horizontal roll rolling load P _HE are obtained from the following formulas from H _WE , rolling loads P _VA and P _HA , and target delivery side thicknesses h _F and h _W.

(Equation 16)

By the rolling loads P _VE and P _HE , the roll gap setting amounts S _VE and S _HE are as follows.

[Equation 17] Alternatively, the roll gap correction amounts ΔS _V and ΔS _{H with} respect to the initial set values S _V and S _H are as follows.

(Equation 18)

The roll gap correction amount obtained as described above is output from the arithmetic unit 21 to the rolling-down control units 23 and 24. The reduction control devices 23 and 24 are the reduction devices 26 and 2, respectively.
The operation signal is output to 7.

In the above description, the influence of the horizontal roll rolling load on the fluctuation amount of the vertical roll rolling load is not taken into consideration. When considering the effect of horizontal roll rolling load,
The P _H in addition to the on the right side of the equation (), the first equation of the formula (7) is added to the following section.

[Equation 19] Then, by the same method as when obtaining the equation (11), ΔH _F
And ΔH _W should be calculated.

[0026]

EXAMPLE A vertical roll: a roll diameter of 420 mm, a body length of 164 mm, a horizontal roll: a roll diameter of 250 mm, a body length of 140 mm, an H-section steel were rolled by the following universal rolling machine. The material of the H-section steel is ordinary steel, and the material dimensions of the rolled material on the inlet side of the rolling mill are as follows. Flange: Width 100 mm, thickness 16 mm Web: Height 180 mm, thickness 8 mm The set temperature of the rolled material on the rolling mill entrance side was 1000 ° C. The flange reduction was 16% and the web reduction was 15%.

As a result of rolling by the method of the present invention under the above rolling conditions, the dimensional accuracy of the flange portion was ± 1.4% and the dimensional accuracy of the web portion was ± 1.5%. On the contrary,
When rolled with a roll gap initially set based on the inlet and outlet thicknesses of the flange and web, and the inlet temperature of the rolled material, the dimensional accuracy of the flange is ± 2.5%.
The dimensional accuracy of the web portion was ± 2.7%.

[0028]

According to the present invention, the variation of the inlet temperature of the rolled material,
The variation of the rolling load is calculated in consideration of the variation of the inlet thickness, the variation of the outlet thickness, and the variation of the rolling load of the vertical roll or the horizontal roll. Therefore, the rolling load can be predicted with high accuracy, and the accuracy of setting the roll gap can be improved. As a result, a product with high dimensional accuracy can be manufactured.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a universal rolling mill for carrying out the present invention.

[Explanation of symbols]

 1 H-section steel 2 H-section steel flange 4 H-section steel web 11 Universal rolling mill 12 Vertical roll 13 Horizontal roll 15 Thickness measuring instrument (for flange) 16 Thickness measuring instrument (for web) 18 Load cell (vertical roll) 19 Load cell (for horizontal roll) 21 Computing device 23 Rolling down control device (for vertical roll) 24 Rolling down control device (for horizontal roll) 26 Rolling down device (for vertical roll) 27 Rolling down device (for horizontal roll)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hide Uchida 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division

Claims (2)

[Claims] 1. A method of rolling a rolled steel, comprising: measuring a rolling load when rolling a rolled material with a universal rolling mill, correcting a roll gap based on the measured rolling load, and rolling a subsequent rolled material. With the inlet temperature, inlet thickness, outlet thickness, and rolling load of vertical or horizontal rolls as the fluctuation factors of the rolling load, the sum of the terms obtained by multiplying the fluctuation amount of each fluctuation factor by the respective influence coefficient changes the rolling load Quantity model formula,
Measure the measured thickness of the rolled material, the measured rolling load, and the variation amount of the rolling load.The temperature of the rolled material is calculated from the model temperature to estimate the rolling load, and the roll gap of the vertical roll and horizontal roll is calculated based on the estimated rolling load. A method for rolling a steel strip, characterized in that it is modified. 2. A method of rolling a bar steel, comprising: measuring a rolling load when rolling a rolled material with a universal rolling mill, correcting a roll gap based on the measured rolling load, and rolling a succeeding rolled material. A method for rolling a steel strip characterized by comprising: On the entry side of the universal rolling mill, measure the thickness of the web and flange of the rolled material respectively.Measure the horizontal roll rolling load and vertical roll rolling load for the thickness-measured portion. Determine the amount of variation in the inlet thickness with respect to the initial setting inlet thickness based on the side thickness and the amount of variation in the rolling load with respect to the initial setting rolling load based on the measured rolling load.Inlet temperature of the rolled material, inlet thickness, outlet thickness, And the rolling load of vertical rolls or horizontal rolls as a fluctuation factor of the rolling load, the sum of the terms obtained by multiplying the fluctuation amount of each fluctuation factor by the respective influence coefficient is used as the rolling load fluctuation amount model formula, and the rolling measured in the step or Measured in steps by determining the inlet side temperature of the rolled material and the rolling load, and the inlet side temperature of the rolled material from the rolling load variation model formula The horizontal roll rolling load and vertical roll rolling load obtained in step from the inlet side thickness of the rolled material, the inlet side temperature of the rolled material obtained in step, and the target outlet side thickness of the rolled material, and Based on the vertical roll rolling load, calculate the roll gap between the horizontal roll and the vertical roll by the gauge meter method. Correct the roll gap between the horizontal roll and the vertical roll to the roll gap determined in the step.