JP2953337B2 - Rolling method for H-section steel - Google Patents

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 an H-section steel, and more particularly to an improvement in dimensional accuracy of a flange.

[0002]

2. Description of the Related Art A hot rolling process for an H-section steel is schematically shown in FIG. A material such as a slab, bloom or beam blank heated to a predetermined temperature in the heating furnace 1 is rolled into a crude steel slab by a breakdown rolling mill 2 and then at least one or more universal rolling mills 3 and edger rolling, respectively. The roll is rolled to a predetermined size by a group of coarse universal rolling mills composed of a mill 4, and is rolled to a product shape and dimension by a finish universal rolling mill 5. In the H-section steel manufactured by such a rolling process, a web thickness t1 and four flange thicknesses t2, t22, t23, t as shown in FIG.
24, widths B1, B2 of the left and right flanges, and deviation S of the center of the web are specified, and it is important to roll these dimensions with good accuracy. It is difficult to carry out the process, and when manufacturing the H-section steel having the required dimensions, the yield has been lowered due to the deviation of the dimensions and the rolling efficiency has been hindered.

[0003] In the breakdown rolling, a crude steel slab is rolled by a plurality of dies as shown in FIG. 3, but the setting position of the centering guide of the material to be rolled, the rolling bite posture or the shape of the dies and the improper pass schedule. Or, it is difficult to always obtain a desired symmetrical coarse steel slab which is symmetrical due to backlash etc., and a coarse steel slab having an uneven cross-sectional shape is a factor that reduces the dimensions of the final product after subsequent universal rolling. It has become. In the group of coarse universal rolling mills, a universal rolling mill having a pair of horizontal rolls and a pair of vertical rolls, the web has a gap between the horizontal roll pairs, and the four flanges have a thickness in the thickness direction due to the gap between the horizontal roll and the vertical roll. And the left and right flange axes are
It is reduced by an edger rolling mill, and these rollings are repeatedly performed until a predetermined size is obtained. In the universal rolling having a horizontal roll paired up and down and a vertical roll paired right and left, it is particularly difficult to uniformly roll the flange thickness at the four locations in the upper, lower, left and right directions.

The first reason for this is that when the sectional shape of the crude steel slab after the breakdown rolling is not symmetrical in the vertical and horizontal directions as shown in FIG. Even if all four of the gaps are equally set and rolled, since the thickness of each part corresponding to the flange of the crude steel slab to be rolled is different,
The rolling reaction force at each of the four flanges is different.
As shown in (1), not only the vertical rolls elastically supported but also the horizontal rolls are displaced in the roll axis direction due to the difference in the rolling reaction force, so that the thickness of each flange portion of the universal rolling mill is not uniform.

[0005] The second reason is that even if the cross-sectional shape of the crude steel slab that has been subjected to breakdown rolling is good in the vertical and horizontal directions, the horizontal roll pair and the vertical roll pair must be formed before rolling in universal rolling. At present, it is extremely difficult to set the desired gap accurately and confirm it, because there is no rolling mill play and an effective roll gap detector, and if the roll gap of a certain pass is inappropriate, the material to be rolled is After rolling, the rolled material becomes non-uniform in thickness from the next pass onward, and as described above, causes a reduction in dimensional accuracy of the final product.

Various studies have been made on dimensional control for optimizing the roll gap in H-beam rolling, and a typical one is a so-called setup control. In this method, since the roll displacement during rolling and the rolling reaction force have a linear relationship, the rolling reaction force is predicted, and the roll gap is set before rolling based on this. As a technique related to this, in a universal rolling mill, a roll gap formed by a horizontal roll pair and a vertical roll pair is adjusted to control the thickness of a flange and a web.
Reference is made to the techniques disclosed in JP-A-3-104714 and JP-A-63-123510. In this technique, when the thickness of the four flange portions of the input material in the universal rolling is not uniform, the flange thickness cannot be made uniform in the actual rolling for the reasons described above.

On the other hand, as a technique for making the thickness of four flanges uniform, there is a technique disclosed in Japanese Patent Application Laid-Open No. 6-15327. According to this technique, the flange 4
Although effective in reducing the non-uniformity of the thickness at various places, there is a drawback in that doing so causes a new dimension defect. In other words, when a crude steel slab of a breakdown rolling mill having four flanges with uneven thickness is used as a raw material and this technology is applied, there is a difference in the rolling reduction in the thickness direction of four flanges in order to eliminate the unevenness. This difference in the rolling reduction results in a difference in the width of the flange, and finally the difference in the width of the flange shown in FIG.
As shown in (1), the leg length of the flange is not uniform, that is, the bias of the web is worsened, and the difference between the left and right flange widths is increased.

Further, while the thicknesses of the four flanges are made uniform, a difference in the width reduction of the four flanges occurs due to a difference in the rolling reduction in the thickness direction of the four flanges. This causes a difference in the leg length of the four flanges, that is, a deviation of the web center. As a technique for reducing the noise, there is a technique disclosed in Japanese Patent Application Laid-Open No. 6-15323. However, even in this technique, as described in detail of the invention, it is not possible to simultaneously eliminate the difference in the length of the flange legs, that is, the deviation of the center of the web, the difference in the width of the right and left flanges, and the uneven thickness of the four flanges.

[0009]

As described above, as described above,
In the conventional universal rolling method, the required flange 4
It was very difficult to satisfy both the uniformity of the thickness at the location and the uniformity of the width of the left and right flanges at the same time. In other words, when trying to fit the dimensions of a certain point within a predetermined tolerance range,
It is possible that the dimensions of other parts may cause deviation. In actual rolling, in the H-section steel immediately after the start of rolling of a certain size, the dimensional accuracy of a certain portion is inferior, and in an extreme case, the tolerance is deviated to cause a decrease in yield. If the correction is attempted, there is a problem that dimensional deterioration of other portions occurs, which hinders the improvement of the yield and the rolling efficiency. In recent years, the dimensional tolerances are strict, as in the case of the H-section steel with the foreign law,
When the size lot was small, the above problem was extremely serious.

The present invention simultaneously satisfies both the required uniformity of the thickness of the four flanges and the uniformity of the width of the right and left flanges, which have been difficult by the prior art in the rolling of the H-section steel. It is an object of the present invention to obtain a method for rolling an H-section steel which realizes a value with high accuracy and further improves a yield and a rolling efficiency.

[0011]

According to the present invention, in the step of rolling an H-section steel through a group of rough universal rolling mills and a finishing universal rolling mill, the thickness of at least four flanges of the material to be rolled, the thickness of the web and the right and left flanges are provided. The width is measured, and if each dimension is different from the target dimension, from the measurement results, the roll gap composed of the upper and lower horizontal roll pairs and the left and right vertical roll pairs and the left and right edges By appropriately setting the roll gap, it is possible to roll an H-section steel having a desired web thickness, four flange thicknesses, and left and right flange widths.

That is, according to the present invention, there is provided a universal rolling mill in which at least one or more horizontal rolls can move in the axial direction and a reduction in the width of the left and right flanges separately from the crude steel slab obtained by the breakdown rolling. At the time of rolling an H-section steel by a row of rough universal rolling mills comprising adjustable edger rolling mills and a row of finishing rolling mills, at least four flange thicknesses, web thickness, left and right at positions close to the coarse universal rolling mill. At least one dimension meter for measuring the flange width is arranged, and a deviation from a target value of each dimension is calculated from the measurement results.
It has the desired dimensions in the subsequent rolling passes without disturbing the shape of the material to be rolled from the rolling reduction of the web material, the reduction ratio of the web thickness, the reduction ratio of the left and right flange width, the deformation characteristics of the material to be rolled, and the characteristics of the rolling mill. The correction amount of the roll gap composed of upper and lower horizontal rolls and vertical rolls and the right and left roll gaps of the edger rolling mill for obtaining the H-section steel is calculated, and the position of each roll is changed based on this result. This is a method for rolling an H-section steel, characterized in that rolling is performed in a number of passes or more.

[0013]

The rough steel slab that has been subjected to breakdown rolling in the hot rolling process of the H-section steel is difficult to obtain a completely symmetrical top, bottom, left and right and has, for example, a cross section as shown in FIG. . A case where the raw steel slab having such a cross section is used as a raw material and rolled through a group of coarse universal rolling mills and a finishing universal rolling mill will be described. In the universal rolling mill, both the horizontal roll pair and the vertical roll pair are supported by an elastic system such as a roll chock and a housing,
This is shown schematically in FIG. When a crude steel slab as shown in FIG. 4 is rolled by this universal rolling mill, a rolling reaction force acts on each roll as shown in FIG. 5, and each roll is displaced by the reaction force. At this time, even if the roll gaps corresponding to the four flange portions are set to be equal, the rolling reaction force at the four flange portions is still small.
The difference is caused by the difference in the reduction ratio due to the uneven thickness at the places, and the displacement is caused by the difference in the reaction force of the left and right vertical rolls.

Further, if a difference occurs in the rolling reaction force acting on the upper horizontal roll, for example, from the left and right of the upper part of the flange, the upper horizontal roll is displaced in the resultant direction of the reaction force, that is, in the axial direction of the horizontal roll. As a result, even if the roll gap corresponding to each flange is set to be uniform in the rolled material after rolling, the thickness of the four flanges is not uniform, and a difference occurs in the rolling reduction at each flange. The width of the flanges is different from each other, which results in a difference between the left and right flange widths. Further, in this universal rolling, when rolling is performed with each roll gap set so as to make the thickness of the four flanges as uniform as possible, the width of the four flanges caused by the difference in the reduction ratio of the four flanges is large. The difference causes a large difference between the left and right flange widths.

Next, when the rolled material having the different left and right flange widths is used as a material and edger rolling is performed with the roll gap for reducing the left and right flange widths set to be equal,
Although the difference between the right and left flange widths is reduced and the left and right flange widths after the edger rolling become substantially equal, as shown in FIG. Will be different. When the material to be rolled having such a cross-sectional shape is subjected to the next universal rolling, the width return amounts of the dog bone portions of the left and right flanges are different, and as a result, the left and right flange widths cannot be made uniform.

Hereinafter, the rolling mill row in the present invention, that is, a universal rolling mill capable of moving a horizontal roll in the axial direction for each pass and an edger rolling mill capable of individually setting a roll gap corresponding to the reduction of the left and right flange widths are described. A method for obtaining the uniformity of the thickness of four flanges, the uniformity of the flanges of the left and right flanges, and the desired dimensions of the web thickness, the flange thickness, and the flange width through the rolling mill row will be described.

The roll displacement characteristics of the universal rolling mill can be expressed as follows by the rolling reaction force, backlash, spring constant of the elastic system supporting the roll, and the like. Here, when describing the roll displacement in universal rolling, particularly the axial displacement of the horizontal roll, the upper and lower horizontal roll positions are conveniently referred to.
The offset amount of the center of the roll gap formed by the horizontal roll pair with respect to the center of the vertical roll in the body length direction is P _L
It is represented by

S _H = F ₁ (P _H , δ _H , S _H0 , K _H ,...) R _F1 = F ₂ (P _F1 , P _F2 , P _F3 , P _F4 , δ _VD , K _VD , R _VD , R _H , K _HT , P _L ,...) R _F2 = F ₃ (P _F1 , P _F2 , P _F3 , P _F4 , δ _VD , K _VD , R _VD , P _L ,...) R _F3 = F ₄ (P _F1 , P _F2 , P _F3 , P _F4 , δ _VF , K _VF , R _VF , R _H , K _HT , P _L , ...) R _F4 = F ₅ (P _F1 , P _F2 , P _F3 , P _F4 , δ _VF , K _VF , R _VF , P _L ,...) (1) _SH ; Horizontal roll gap δ _H ; Horizontal roll reduction play _{SH 0} ; No load horizontal roll gap K _H ; Horizontal Spring constant of the roll support system P _H ; Rolling reaction force R _Fi acting on the horizontal roll R _Fi ; Flange opposed roll gap P _Fi ; Flange rolling reaction force i: 1-4, flange position δ _j ; Vertical roll play R _Vj ; Vertical roll position j: D, F, left and right Roll K _Vj; spring constant of the vertical roll support system R _H; upper horizontal roll axial direction movement amount K _HT; spring constant of the horizontal roll axis direction support system

Next, the rolling reaction force of each portion shown in FIG. 5 in the universal rolling is mutually affected by the reduction ratio of the web portion and the four flanging portions, and is further affected by the shape of the rolling material and the dimensions of each portion. Therefore, it can be expressed as follows. P _H = F ₆ (tw ₁ , t _{F11 to} t _F14 , B _{11 to} B ₁₄ , t _w2 , t _{F21 to} t _F24 , B _{21 to} B ₂₄ , P _F1 to ₄ ,...) P _H1 = F ₇ ( _{t w1, t F11 ~t F14,} B 11 ~B 14, t w2, t F21 ~t F24, B 21 ~B 24, ··) P H2 = F 8 (t w1, t F11 ~t F14, B 11 _{~B 14, t w2, t F21} ~t F24, B 21 ~B 24, ··) P H3 = F 9 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t _{F24, B 21 ~B 24, ··} ) P H4 = F 10 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F24, B 21 ~B 24, ··) ... (2) t _wi ; web thickness t _Fij ; flange thickness i; 1: dimension before universal rolling 2: dimension after universal rolling B _ij ; flange width j; 1-4: four flange portions

The width of the four flanges in the universal rolling can be expressed as follows. _{B 21 = F 11 (t w1} , t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F24, ··) B 22 = F 12 (t w1, t F11 ~t F14, B 11 _{~B 14, t w2, t F21} ~t F24, ··) B 23 = F 13 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F24, ··) B _{24 = F 14 (t w1,} t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F24, ··) ... (3) t wi; web thickness t _Fij; flange thickness i; 1: Dimension before universal rolling 2: Dimension after universal rolling B _ij ; Flange width j; 1-4: Four flanges

From the above non-linear relational expression, it is complicated or difficult to express the dimensions of each part after rolling. When correcting the roll gap in actual rolling, it is sufficient to find the amount of correction. Therefore, if only the amount of change is considered in order to make these relationships linear, the amount of change in the dimensions of each part after rolling can be expressed by the following linear relational expression. _{Δt w2 = f 1 (Δt w1} , Δt F11 ~t F14, ΔB 11 ~ΔB 14, ΔS H, ΔR H, ΔR VD, ΔR VF, ΔP L, Δt F21 ~t F24, ΔB 21 ~B 24) Δt F21 _{= f 2 (Δt w1, Δt} F11 ~Δt F14, ΔB 11 ~B 14, ΔS H, ΔR H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F22 ~t F24, ΔB 21 ~B 24) Δt _{F22 = f 3 (Δt w1,} Δt F11 ~t F14, ΔB 11 ~B 14, ΔS H, ΔR H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F21, Δt F23 ~t F24, ΔB 21 ~ _{B 24) Δt F23 = f 4} (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔS H, ΔR H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F21 ~t F22, Δt F24 _{, ΔB 21 ~B 24) Δt F24} = f 5 (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔS H, ΔR H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F21 ~t _{F23, ΔB 21} ~B _{24) ΔB 21 = ΔB 22 = f (} Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔS H, Δ R H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F21 ~t F24, ΔB 23 _{~B 24) ΔB 23 = ΔB 24} = f (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔS H, Δ R H, ΔR VD, ΔR VF, ΔP L, Δt w2, Δt F21 ~t _F24 , ΔB ₂₁ -B ₂₂ ) (4)

[0022] delta; t show a variation _wi; web thickness t _Fij; flange thickness i; 1: universal rolling dimension before 2: After universal rolling dimension B _ij; flange width j; 1 to 4: flange 4 places S _H Horizontal roll gap R _H ; horizontal roll axial movement amount R _VD ; R _VF ; vertical roll position _RL ; offset amount of horizontal roll gap center

Similarly, in the edger rolling, the roll displacement characteristics can be expressed as follows by the rolling reaction force, the play, the spring constant of the elastic system supporting the roll, and the like. S _D = G ₁ (P _D , σ _D , S _D0 , K _ED ,...) S _E = G ₂ (P _F , σ _F , S _F0 , K _EF ,...) (5) S _D , S _F : Left and right edger roll gaps S _D0 , S _F0 ; Left and right edger roll gaps σ _D , σ _F ; Left and right edger roll play K _ED , K _EF ; Spring constants of edger roll left and right support systems P _D , P _F ; Left and right edger rolls Rolling reaction force

The rolling reaction force in edger rolling can be expressed as follows. P _D = G ₃ (tw ₁ , t _{F11 to} t _F14 , B _{11 to} B ₁₄ , t _w2 , t _{F21 to} t _F24 , B _{21 to} B ₂₄ ...) P _F = G ₄ ( _{tw 1} , t _F11 to t _F14 , B _{11 to} B ₁₄ , t _w2 , t _{F21 to} t _F24 , B _{21 to} B ₂₄ ... (6) t _w1 ; web thickness t _Fij ; flange thickness i; 1: dimensions before edger rolling 2: Edger dimensions after rolling B _ij ; Flange width j; 1-4: Four flanges

Further, the thickness of each part in the edger rolling can be expressed as follows. _{t w2 = G 5 (t w1} , t F11 ~t F14, B 11 ~B 14, t F21 ~t F24, B 21 ~B 24, ··) t F21 = G 6 (t w1, t F11 ~t F14 _{, B 11 ~B 14, t w2} , t F22 ~t F24, B 21 ~B 24, ··) t F22 = G 7 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t _{F21, t F23 ~t F24, B} 21 ~B 24, ··) t F23 = G 8 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F22, t F24, _{B 21 ~B 24, ··) t} F24 = G 9 (t w1, t F11 ~t F14, B 11 ~B 14, t w2, t F21 ~t F23, B 21 ~B 24, ··) ... ( 7) t _wi ; web thickness t _Fij ; flange thickness i; 1: dimensions before edger rolling 2: dimensions after edger rolling B _ij ; flange width j; 1-4: four flange portions

Here, as in the case of universal rolling,
The amount of change in the dimensions of each part after the edger rolling can be expressed by seven relational expressions as follows. _{Δt w2 = g 1 (Δt w1} , Δt F11 ~t F14, ΔB 11 ~B 14, ΔSD, ΔSF, Δ t F21 ~t F24, ΔB 21 ~B 24) Δt F21 = g 2 (Δt w1, Δt F11 ~ _{t F14, ΔB 11 ~B 14,} ΔSD, ΔSF, Δt w2, Δt F22 ~t F24, ΔB 21 ~B 24) Δt F22 = g 3 (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔSD _{, ΔSF, Δt w2, Δt F21} , Δt F23 ~t F24, ΔB 21 ~B 24) Δt F23 = g 4 (Δt w1, Δt F11 ~t F14, B 11 ~B 14, ΔSD, ΔSF, Δ t F21 ~ _{t F22, Δt F24, ΔB 21} ~B 24) Δt F24 = g 5 (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔSD, ΔSF, Δt w2, Δt F21 ~t F23, ΔB 21 ~B _{24) ΔB 21 + ΔB 22 =} g 6 (Δt w1, Δt F11 ~t F14, ΔB 11 ~B 14, ΔSD, Δ SF, Δt w2, Δt F21 ~t F24, ΔB 23 ~B 24) ΔB 23 + ΔB _{24 = g 7 (Δt w1,} Δt F11 ~t F14, ΔB 11 ~B 14, ΔSD, Δ SF, Δt w2, Δt F21 ~t F24, ΔB 21 ~B 22) ... (8) Δ; shows a variation . t _wi; web thickness t _Fij; flange thickness i; 1: edger pre-rolling dimensions 2: After edger rolling dimension B _ij; flange width j; 1 to 4: flange 4 places S _D, S _F; lateral vertical nip

Here, when at least the thickness of the web, the thickness of four flanges, and the width of the right and left flanges are measured by a dimension meter arranged at a position close to the universal rolling mill, a deviation from a target value is obtained. The details of the method of obtaining an H-section steel having a desired size in a subsequent rolling pass according to the present invention will be described. The deviation between the target dimension and the measurement result at the time of measurement by the dimension gauge or the amount of change in the dimension, and the correction amount of the roll gap are expressed using Δ, and the value set or targeted before the dimension measurement is expressed without Δ Here, an example will be described in which the deviation of the dimension of each part from the measurement result is eliminated by one-pass rolling including universal rolling and edger rolling once each.

FIG. 9 shows a universal rolling mill and an edger rolling mill, a dimensional change amount of a material to be rolled at each position, and a roll gap correction amount. The deviation of the dimensions of each part from the target value on the entry side of the material to be rolled is known, and the amount of change in the dimensions of each part after the end of one-pass rolling is “0” to match the target value, and is known. It becomes 14 pieces. What is to be obtained, that is, what is unknown, is the roll gap correction amount for correcting the dimensional deviation on the entry side and the dimensional change amount of the material to be rolled by the corrected roll gap, and the number is 14 pieces. .

The relational expressions for obtaining the unknown dimensional change amount and the roll gap correction amount are expressed by Expressions (4) and (8). In the universal rolling, the web thickness after the rolling and four positions are calculated. Are seven relational expressions relating to the respective changes in the flange thickness and the left and right flange widths. Similarly, in the edger rolling, there are seven relational expressions for each dimensional change. It is determined by calculation. In other words, the unknown quantity to be obtained and the number of relational expressions become equal to 14, and it is possible to uniquely obtain the roll gap correction amounts for correcting the entry-side dimensional deviation of the material to be rolled in one pass. That is, in order to finish the uniformity of the flange thickness at four places, the uniformity of the right and left flange widths and the absolute values of these dimensions to the target dimensions, the universal rolling mill according to the present invention can move the horizontal roll in the axial direction. In addition, in the edger rolling mill, it is essential that the roll gap corresponding to the reduction of the left and right flange widths can be individually set, and further, at least the web thickness, the four flange thicknesses, and the left and right flange widths are measured. Means that it is essential, and it is impossible with the prior art.

Next, according to the present invention, by rolling in two or more passes,
The example of the method of correcting the deviation of the input side dimension of the material to be rolled from the target value will be described. FIG. 10 shows the universal rolling mill and the edger rolling mill, the dimensional change amount of the material to be rolled at each position, and the roll gap correction amount. As in the case of correction in one pass, the deviation of each part dimension from the target value on the entry side of the material to be rolled is known from the measurement result of the dimension meter, and the amount of change in each part dimension after the end of rolling matches the target value. Is known to be “0”,
The number is 14 pieces.

What is to be obtained, that is, unknown is the roll gap correction amount for correcting the dimensional deviation on the entry side and the dimensional change amount of the material to be rolled by the corrected roll gap. It is que. The relational expression for calculating the unknown dimensional change amount and the roll gap correction amount is the same as in the case of correcting in one pass, and in universal rolling, each change in the web thickness after rolling, the flange thickness at four locations, and the left and right flange widths There are seven relational expressions relating to the amount, and also seven relational expressions for each dimensional change amount in edger rolling. In the case shown in FIG. 10, a total of 28 relational expressions are used.

Further, when the dimension is to be corrected in two or more passes, more conditional expressions are required. In other words, the number of unknown quantities is now 35 and the relational expression is 28, and all unknown quantities cannot be uniquely obtained. This is because, as described above, the dimensional deviation on the entry side can be corrected by one-pass rolling, and therefore, when corrected by two or more passes, a relational expression of the correction method is required. . This is not a disadvantage in terms of dimensional correction, but rather an advantage in actual rolling. That is, when performing dimension correction in two or more passes, it is possible to consider a relational expression that suppresses a shape defect such as warpage or bending of a rolled material during rolling that could not be considered in one-pass rolling, in dimension correction. Because.

Shape defects such as warpage and bending at the time of rolling are caused by an excessive difference in rolling reduction between four flange thicknesses. Therefore, when the dimension is corrected by rolling two or more passes, four locations are required in one pass. Compared with the reduction ratio required to eliminate the flange thickness, the reduction ratio of each portion of the flange in each pass can be reduced, and the dimension can be corrected while suppressing the shape defect. Various relational expressions can be conceived for performing dimension correction in two or more passes. For example, it is known that a shape defect is less likely to occur when the difference between the reduction ratios of the flange thicknesses is the same and when the flange thickness is thinner than when the flange thickness is thin. It becomes the formula of. ΔS _H1 / ΔS _H2 = α ₁ ΔS _D1 / ΔS _D2 = α ₆ ΔR _VD1 / ΔR _VD2 = α ₂ ΔS _F1 / ΔS _F2 = α ₇ ΔR _VF1 / ΔR _VF2 = α ₃ ΔR _H1 / ΔR _H2 = α ₄ α _i ≧ 1.0 ΔP _L1 / ΔP _L2 = α ₅ (9)

When these seven relational expressions are prepared and combined with the above-mentioned relational expression of the dimensional change amount of each part, the relational expression becomes 35, and the roll gap correction amount for correcting the entry-side dimensional deviation in two passes. Can be obtained. Here, an example of dimensional correction by two passes has been described, but correction in three or more passes is also possible. Furthermore, in the present invention, as can be easily inferred from the above description, the dimensions at the end of rolling are intentionally made non-uniform, that is, it is possible to modify the roll gap to arbitrarily change the dimensions of each part. Let me add that.

Further, in the present invention, it is not necessary to simultaneously measure at least the web thickness, the four flange thicknesses, and the left and right flange thicknesses. For example, as shown in FIG. It is effective to measure the entrance side and measure the flange thickness at four locations between the universal rolling mill and the edger rolling mill. In the case of measuring the dimensions in this manner, if the above-mentioned case is applied to the case where the dimensions are corrected by the two-pass rolling, only the amount by which the deviation from the target value is known is changed, and the number of the known amounts is also unknown. It is clear that the present invention is effective because neither the number nor the relational expression changes.

FIG. 12 shows rolling equipment suitable for carrying out the present invention. In FIG. 12, E is a heating furnace, A is a breakdown rolling mill, B and B 'are coarse universal rolling mills, and C and C'.
Is an edger rolling mill, D is a finishing rolling mill, E is a hot dimension gauge, and F is an arithmetic unit. The arithmetic unit F calculates the deviation from the target value of each dimension and the measurement result of the hot dimension meter E, and corrects the dimensional deviation based on the previously obtained relational expression to correct each roll gap. The amount and the dimensional change of the material to be rolled are calculated. Further, all roll positions are adjusted based on the result of adding the roll gap correction amount to the set roll gap value. By performing such a process at least once, the uniformity of the flange thickness at four places, the uniformity of the width of the left and right flanges, the web thickness, the flange thickness,
The absolute value of the flange width can be finished to a desired size. According to the present invention, even in a rolled material immediately after the start of rolling of a certain size, a desired dimension is not deviated, a decrease in yield due to a deviation in dimension can be eliminated, and an improvement in rolling efficiency can be achieved.

[0037]

EXAMPLE Using the equipment shown in FIG.
An H-section steel having a diameter of 00 mm and a flange width of 300 mm was hot-rolled, and the dimensions of the product in the case where the present invention was applied and in the case where it was not applied, that is, the conventional technology were investigated. In the embodiment, the present invention is applied to the final five-pass rolling of the coarse universal rolling,
When determining the dimensional deviation from the target dimension, the average value of the measured values by the dimension meter near the center in the longitudinal direction of the material to be rolled was used. Further, in the embodiment, α _i in the above-mentioned equation (9) is a coefficient proportional to the thickness of each part, so that the disorder of the shape during rolling is not a problem. Investigation results of the web thickness, the four flange thicknesses, and the right and left flange widths are shown in Table 1 in comparison with the case where the present invention is not applied (conventional method). As is clear from Table 1, in the present invention, the uniformity of the flange thickness and the uniformity of the left and right flange widths are remarkably improved, and the average value (absolute value) of the web thickness flange thickness and the flange width is also a desired size. It was almost equal, and it was confirmed that it was effective in achieving good dimensional accuracy.

[0038]

[Table 1]

[0039]

As described above, according to the present invention, it is possible to roll an H-section steel with high dimensional accuracy with respect to flange thickness, flange width, and web thickness. The efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a hot rolling step of an H-section steel.

FIG. 2 is an explanatory diagram of dimensions of each part of an H-section steel.

FIG. 3 is an explanatory view of a groove type of a breakdown rolling mill.

FIG. 4 is a diagram showing a cross-sectional shape of a crude steel slab after finishing breakdown rolling.

FIG. 5 is an explanatory diagram showing displacement and rolling reaction force of a vertical roll and a horizontal roll when the crude steel slab of FIG. 4 is rolled.

FIG. 6 is a diagram showing a cross-sectional shape of an H-shaped steel in a case where a difference occurs in a width expansion of a flange due to a difference in rolling reduction.

FIG. 7 is an explanatory diagram showing a support system for a horizontal roll and a vertical roll of a universal rolling mill.

FIG. 8 is an explanatory diagram of an H-shaped steel dog bone.

FIG. 9 shows a case where deviation is eliminated by rolling in one pass.
It is explanatory drawing which showed the universal rolling mill and the edge rolling mill, the dimensional change amount of the to-be-rolled material in each position, and the roll clearance correction amount.

FIG. 10 is an explanatory diagram showing a universal rolling mill and an edge rolling mill, a dimensional change amount of a material to be rolled at each position, and a roll gap correction amount in a case where deviations are eliminated by two or more passes of rolling.

FIG. 11 is an explanatory view showing a measurement point of a flange in the present invention.

FIG. 12 is a diagram showing an example of arrangement of rolling equipment to which the present invention is applied.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukio Takashima 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Yoshihisa Yoshida 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan (58) Investigated field (Int.Cl. ⁶ , DB name) B21B 37/16 B21B 1/08

Claims (1)

(57) [Claims] 1. A universal rolling mill in which a horizontal roll is movable in an axial direction, and an edger rolling mill in which a flange width reduction roll gap on a drive side and a free side flange reduction roll can be individually set. In a rolling method using a group of universal rolling mills for rolling H-beams provided with at least one base, at least one
When the H-shape steel is rolled using the crude steel slab after forming and rolling, a hot dimension gauge is arranged at least four flange thicknesses, a web thickness, and two right and left flange widths by the hot dimension gauge. Are measured, the deviation from each target dimension is calculated based on the measurement result, and the rolling reaction force at the time of dimension change and the interaction between the flange and the web are taken into account,
The horizontal roll gap of the universal rolling mill, the amount of movement in the horizontal roll axial direction, the gap between the vertical roll and the horizontal roll, the position of the center of the horizontal roll gap with respect to the center position of the vertical roll in the body length direction, and free from the drive side of the edger rolling mill A method of rolling the H-section steel by changing the flange width reduction gap on the side by rolling one or more passes thereafter.