JP3380423B2 - Roller straightening 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 roller straightening method for H-section steel, in which a plurality of straightening rolls are arranged with variable pitches to straighten the H-section steel to be straightened.

[0002]

2. Description of the Related Art Generally, roller straightening of H-section steel is performed by using a roll straightening roller straightening machine in which a plurality of rolls are arranged in a staggered pattern and the roll pitch can be changed. Since the sagging occurs when the web is pressed, the web is pressed to indirectly give the elasto-plastic deformation to the flange to correct it.

As the straightening conditions in the roll pitch variable type roller straightening machine, there are two roll pitches and the amount of roll reduction. Each of these parameters does not mean that can be set independently, it neither correctable. Therefore when having it is both related affect straightening effect is in fact well known to empirically On the contrary, this is also a difficult point to correct.

As a conventional roller straightening method for H-section steel,
For example, there is one described in JP-A-54-57460. In this conventional example, the working curvature to be imparted to the material to be straightened at each roller position is determined from the relationship between the bending distribution of the H-section steel before straightening, that is, the initial warp amount and the bending distribution allowed for the product after straightening, that is, the allowable warp tolerance. Then, the straightening roller interval, that is, the roll pitch that enables the cross-sectional dimension accuracy to be within the target range, is estimated from the relationship between the web height elongation and the working curvature with the roll pitch ratio as a parameter, and the working curvature and the estimated straightening are estimated. The position of the straightening roller is determined by obtaining the setting coordinates of the straightening roller from the roller interval.

[0005]

However, in the above-mentioned conventional roller straightening method for H-section steel, the index for determining the roll pitch is the increase amount of the web height generated during straightening. The web height increase amount is related to the processing curvature by using the ratio of the front-stage roll pitch and the rear-stage roll pitch as a parameter and is associated with the processing curvature. If many types occur and the steel type is changed, the yield stress will change even with the same size.Therefore, the straightening load will increase as the yield stress increases if the straightening curvature differs under the same straightening conditions. There is an unsolved problem that the product shape is deteriorated due to the increase in the size and the increase in the height of the web.

Further, in the conventional example, the plastic deformation history of the flange at the time of straightening is determined from the amount of reduction and the roll pitch, and since different processing curvatures are determined for each size, the curvature distribution of each roll is different and the roll pitch is different. There is also an unsolved problem that the plastic deformation history determined from the balance with the reduction amount is different. Here, an error always occurs between the model and the actual straightening machine. In such a case, a method is generally adopted in which the amount of warp is made zero by adjusting the appropriate roll reduction amount.However, due to the different plastic deformation history during warp adjustment that cannot be avoided on the actual line. Since the influence coefficient of each roll is different for each size, there is an unsolved problem that it takes a lot of effort to adjust the influence coefficient.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and the same plastic deformation history can be traced even when the size or steel type is changed.
It is an object of the present invention to provide a roller straightening method for H-section steel, which can easily construct the reduction correction control system.

[0008]

[0009]

[Means for Solving the Problems] To achieve the above object
In the roller straightening method for H-section steel according to claim 1 , the roller straightening machine in which a plurality of straightening rolls are arranged at variable pitches is used to roll down the web of the H-section steel so that the flange is elastic-plastic. In a roller straightening method for H-section steel that is deformed and straightened, an optimum roll pitch is obtained from the limit of occurrence of web cracking, the pitch of the straightening roll is set, and then the set roll pitch and warpage after straightening are set. The amount of reduction given to the flange is determined based on the basic reduction pattern of each straightening roll set so that the amount becomes zero, and the web reduction amount corresponding to the determined amount of reduction given to the flange is corrected by the straightening load and the straightening target. It is determined by using the ratio of the web and flange reduction amounts obtained from the cross-sectional shape of the H-section steel, and the straightening roll reduction control is performed with the determined web reduction amount. There.

Further, in the roller straightening method for H-section steel according to the second aspect, the flange is formed by rolling down the web of H-section steel with a roller straightening machine having a plurality of straightening rolls arranged at variable pitches. In a roller straightening method for H-section steel, in which elasto-plastic deformation is applied to the straightening roll, the optimum roll pitch is determined from the limit of occurrence of web cracking, the pitch of the straightening roll is set, and then the set roll pitch and straightening are set. Determine the amount of reduction given to the flange based on the basic reduction pattern of each straightening roll set so that the amount of warp afterwards becomes zero, and determine the amount of web reduction corresponding to the determined amount of reduction given to the flange as the straightening load. , And based on the reduction amount difference between the web and the flange, which is obtained from the cross-sectional shape of the H-section steel to be corrected, and performs the roll control of the straightening roll with the determined web reduction amount. It is characterized in that was.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a roller straightening machine 2 for straightening an H-shaped steel 1. The roller straightening machine 2 has nine straightening rolls R ₁ to which the roller pitch is adjustable and which are arranged in a staggered pattern. has R _9, together with the roll pitch L between these straightening rolls R ₁ to R ₉ is adjusted to an equal pitch by a roll pitch adjustment device RP, odd straightening roll R _j of straightening rolls R ₁ to R ₉ (J = 1,
The amount of reduction 3, 5, 7, 9) is adjusted by a reduction amount adjusting device PA _{j including an} electric motor or the like.

Here, the H-section steel 1 to be corrected is shown in FIG.
As shown in FIG. 5, the web 1a extending in the left-right direction and the left and right flanges 1b, 1c extending in the up-down direction at both ends of the web 1a are formed in an H shape, and the web height is H,
Flange width is B, web thickness is t _W , flange thickness is t
_F and the corner radius are shown as r.

Then, each of the reduction amount adjusting devices PA _j is controlled by a controller 3 composed of a microcomputer or the like. An input device 4 such as a keyboard is connected to the controller 3 and a CRT is provided.
A display device 5 such as a display is connected, and predetermined arithmetic processing is performed on the basis of the cross-sectional shape and standard of the H-section steel input from the input device 4 to prevent web breakage of the straightening rolls R _{1 to} R _9. The optimum roll pitch is calculated, and the optimum amount of reduction given to the flange is calculated according to the basic reduction pattern of each straightening roll set so that the amount of warp after straightening is zero based on this optimum roll pitch, and corresponding The web reduction amount is calculated, and a value obtained by adding the relief amount of the straightening roll to this is set as the web reduction amount, and each reduction amount adjustment device PA _j is controlled based on this value.

Now, the above-mentioned correction principle will be described below.
First, the elastic limit curvature κ _y when the flange end reaches the yield stress is expressed by the following equation (1).

Κ _y = 2σ _y / (E · B) (1) where σ _y is the yield stress, E is the Young's modulus, and B is the flange width. Similarly, the elastic limit bending moment M _y when the flange end reaches the yield stress is expressed by the following equation (2).

M _y = Z · σ _y = (⅓) t _F B ² σ _y (2) where Z is the section modulus and t _F is the flange thickness. Further, the curvature κ and the bending moment M are respectively defined by elastic limit curvature κ.
The _y and elastic limit bending moment M _y curvature coefficient λ and moment coefficients as dimensionless numbers by dividing μ defined below (3) and (4).

Λ = κ / κ _y (3) μ = M / M _y (4) Then, the amount of warpage after correction is determined by the curvature coefficient λ and the moment coefficient μ. It is a deformation history represented by the relationship of.
An example of the relationship between the curvature coefficient λ and the moment coefficient μ representing the deformation history is expressed by simulation as shown in FIG. That is, with the curvature coefficient λ ₁ and the moment coefficient M ₁ of the straightening roll R ₁ on the entry side as the starting points,
Then, while drawing a hysteresis curve, it gradually converges so that the curvature coefficient λ becomes zero, and is determined from the curvature coefficient λ ₈ and the moment coefficient M ₈ of the straightening roll R ₈ immediately before the final straightening roll R ₉ on the exit side. Final straightening roll R ₉
The curvature coefficient λ _{9 at} is less than the allowable bending amount.

Therefore, in order to set the warp amount after correction to "0", it is important to select the basic rolling pattern in consideration of the deformation history. On the other hand, the amount of warpage on the inlet side normally causes variations during rolling and cooling, which are the preceding processes, and the variation of the inlet side warpage Δκ ₀ is not adjusted by adjusting the reduction pattern according to the inlet side warpage. On the other hand, it is possible to reduce the variation in the amount of warp on the outgoing side by giving a large curvature in the first bending, as shown in FIG.

Further, a roll straightening machine 1 for imparting elasto-plastic deformation
In the case of different roll pitches L ′, the same bending process as when corrected with the condition flange width B ₀ , the yield stress σ _y0 , the roll pitch L ₀ and the reduction amount δ ₀ when the basic rolling pattern is determined. In order to achieve this, the rolling reduction amount δ ′ of each roll is determined according to the similarity rule of the roll straightening machine 1 by the elastic limit curvature κ _y expressed by the formula (1) and the elastic limit bending moment M expressed by the formula (2). _{When y} is set, the following equation (5) should be calculated.

Δ ′ = (κ _y ′ / κ _y0 ) (L ′ / L ₀ ) ² δ ₀ ………… (5) Therefore, the roll pitch is fixed for a certain cross section series and the amount of warpage after straightening By experimentally obtaining a basic reduction pattern that represents the reduction amount of each straightening roll R _{1 to} R ₉ such that the value becomes “0”, the reduction amount given to the flange can be determined even when the series is changed to the sectional type. If it is determined according to the above equation (5), the same bending process, that is, substantially the same deformation history can be performed, and the warp after correction can be made "0".

The straightening load P _i of each roll R _i (i = 1, 2, ... 9) when the roll pitch is L can be expressed by the following equation (6). P _i = (M _y / L) p _i (6) Here, p _i is a dimensionless constant obtained when selecting the basic rolling pattern and represents the basic load pattern. Specifically, the following formula (7) is used. It is represented by the function shown in.

P _i = p _i [(δ ₁ / κ _y L ² ), ..., (δ _k / κ _y L ² )] (7) However, k ≦ i. On the other hand, the limit load P of cracks generated at the roots of the web 1a and the flanges 1b and 1c due to the load applied to the web 1a during straightening through various H-shaped steels.
_C was determined experimentally. The limit formula created from this experimental result is represented by the following formula (8), and this crack limit load P _C is H
Web thickness B qualitatively depends on the series section of shaped steel
The larger the corner radius r, the larger the limit load P _C.

P _C = f (t _W , H, t _F , B, r) (8) At this time, in order to prevent web cracking, the maximum value P _MAX of the straightening load is (9) ) As expressed by the formula, the limit load P _C
Must be:

P _MAX = (M _y / L) p _MAX ≦ P _C (9) Then, the roll pitch L ^* is determined according to the following formula (10) so as to satisfy the condition of the above formula (9). To do.

L ^* = M _y · p _MAX / P _C (10) As a result, based on the roll pitch L ^* between the straightening rolls, the following formula (11) corresponding to the above formula (5) is obtained. The optimum reduction amount δ _Fj ′ given to the flange of each straightening roll R _j is calculated in accordance with

Δ _Fj ′ = (κ _y ′ / κ _y0 ) (L ^* / L ₀ ) ² δ _0j (11) By the way, the amount of reduction given by the above equation (11) is the flange 1
b, 1c, not the amount of reduction given to the web 1a, but the amount of reduction δ _Wj given to the web 1a and the amount of reduction δ _Fj given to the flange in the straightening of the H-section steel that _{reduces the} web 1a. Does not match.

For this reason, the relationship between both rolling reductions is given in (12) below.
As shown in the equation, the reduction ratio function α was used, and the reduction ratio function α was obtained as a function of the series sectional shape of the H-section steel and the straightening load P as shown in the following equation (13).

Δ _Wj ′ = (1 / α) δ _Fj ′ (12) α = α (t _W , H, t _F , B, r, P) (13) Next, The operation of the above embodiment will be described with reference to the flowchart of FIG. 5, which shows an example of the arithmetic processing procedure in the controller 3.

First, a reference flange width B (for example, 300 mm) and a flange thickness t _F (for example, 15 mm) are used in advance.
In the roller straightening machine 2 in which the basic roll pitch L ₀ of the basic H-section steel having the yield stress σ _y0 (for example, 30 kg / mm ² ) is adjusted to, for example, 1400 mm, the amount of warpage after straightening is performed by following the deformation history of FIG. There was corrected so that "0", to measure the reduction amount [delta] _0j of each straightening roll R _j at this time, as shown in FIG. 7, at the same time, dimensionless constant p of each straightening roll R _j
The basic load pattern _i is calculated by performing the calculation of the above-mentioned formula (7), the maximum value of the calculated dimensionless constants p _i is set as p _MAX , and the elastic limit is calculated according to the above formula (1). Calculate the curvature κ _y0 and use these as the controller 3
It is stored in the internal memory 6.

In this state, the arithmetic processing of FIG. 5 is executed. First, in step S1, the sectional shape data of the H-section steel as the material to be straightened is input and the steel type data thereof is also input. Here, the web height H, the flange width B, the web thickness t _W , the flange thickness t _F, and the corner radius r of the H-section steel are set as the cross-sectional shape data, and the yield stress σ of the H-section steel is set as the steel type data. _y is set.

Next, in step S2, the equations (1) and (2) are calculated based on the input shape data and steel type data, and the elastic limit curvature κ _y ′ and the elastic limit bending moment are calculated. M _y ′ is calculated and stored in a predetermined storage area of the memory 6.

Next, in step S3, the empirical formula (8) is calculated based on the cross-sectional shape data to calculate the web cracking limit load P _C. Next, in step S4, the calculation of the equation (10) is performed to calculate the optimum roll pitch L ^{* at} which no web crack occurs.

Next, in step S5, the elastic limit curvature κ _{y0 of the} basic H-section steel stored in the memory 6, the roll pitch L ₀ , the rolling reduction amount δ _0j of each straightening roll R _j , and the straightening target. The formula (11) is calculated based on the elastic limit curvature κ _y ′ of the H-section steel and the optimum roll pitch L ^* to determine the flange reduction amount δ _Fj ′ given to the flanges 1b and 1c in each straightening roll R _j . calculate.

Next, in step S6, the flange reduction ratio function α is calculated by performing the calculation of the equation (12) based on the sectional shape data of the H-section steel to be straightened and the straightening load P. Then, the process proceeds to step S7, and the optimum web reduction amount given to the web 1a is obtained by performing the calculation of the equation (13) based on the flange reduction amount δ _Fj ′ calculated in step S5 and the flange reduction ratio function α. δ _Wj ′
Is calculated, and then the process proceeds to step S8.
According to the equation (4), the correction web reduction amount δ _Wj ^* is calculated by correcting the play of the support member such as the bearing for supporting the straightening roll R _i and the straightening roller displacement caused by the rigidity of the roll and the straightening machine.

Δ _Wj ^* = β · δ _Wj ′ + γ (14) where β is a coefficient relating to the rigidity of the roller straightening machine 2 and the straightening roll, and γ is a constant relating to backlash, which are roller straightening machines. It is determined by the characteristics of.

Next, in step S9, the calculated optimum roll pitch L ^* is output to the roll pitch adjusting device RP, and the corrected web reduction amount δ _Wj ^* is output to the reduction amount adjusting device PA _j .

Therefore, the roller straightener 2 adjusts the roll pitch to the optimum roll pitch L ^* corresponding to the H-section steel to be straightened, and the reduction amount of each straightening roll R _j is the corrected reduction amount δ _Wj ^*. Adjusted to.

At this time, for the optimum roll pitch L ^* , the web cracking limit load P _C is calculated based on the limit formula obtained in the experiment, and the roll pitch L ^* is set so as not to exceed the web cracking limit load P _C. Since it is set, it is possible to reliably prevent the occurrence of web cracks during the straightening by the roller straightening machine 2, and the optimum roll pitch L ^* and the elastic limit curvature of the set H-section steel to be straightened are set. κ _y ′
And the roll pitch L ₀ and the elastic limit curvature κ _{y0 in} the basic rolling pattern of the basic H-section steel set in advance according to the similarity rule of the roller straightening machine, the rolling reduction amount δ _Fi ′ given to the flange of each straightening roll R _j. Roller straightener 2
The deformation history at is substantially the same as the deformation history of the basic H-section steel shown in FIG. 3, and stable warp correction is possible for H-section steel of any steel type and cross-sectional shape.

Moreover, the web reduction amount δ _Wj of the H-section steel to be corrected is calculated from the calculated reduction amount δ _Fi ′ given to the flange of each straightening roller R _j by using the reduction ratio function α based on the sectional shape data and the straightening load. Since ′ is calculated,
The amount of web reduction δ _Wj ′ from the amount of reduction δ _Fi ′ applied to the flange
Can be converted accurately and easily, and more stable warp correction can be performed.

Further, when the size and steel type of the H-section steel are changed, the roll pitch is determined based on the web cracking limit load, and the amount of reduction applied to the flange is determined based on the determined roll pitch and the basic reduction pattern. Since it is only necessary to perform the above, it is possible to easily construct a reduction amount correction control system.

Warp before and after straightening when straightening H-shaped steels of standard sizes H300 × 300 × 10/15 and H900 × 300 × 16/28 using the straightening method of the first embodiment. The measurement result of the amount is shown in FIG. The basic rolling pattern used at this time is, as shown in FIG.
H-section steel with a flange width of 300 mm has a roll pitch L of 14
When the straightening amount is 00 mm and the warping amount after straightening is straightened, the rolling pattern is a rolling pattern. The rolling amount of the _first straightening roll R ₁ is 4 mm, and the rolling amount of the _third straightening roll R ₃ is 1 mm. 0.8 mm, the reduction amount of the _fifth straightening roll R ₅ is 0.8 mm, the reduction amount of the seventh straightening roll R ₇ is 0.5 mm, and the reduction amount of the ninth straightening roll R ₉ is 0 m.
It is set to m.

During the straightening of these H-section steels, no web cracking occurred, and the amount of warp after straightening was -20 m as shown in FIG.
Even when the variation was within the range of m to +20 mm, the amount of warp after the correction was entirely within the allowable range of -4 mm to +4 mm, and good correction results could be obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the conversion from the reduction amount δ _Fj ′ given to the flange to the web reduction amount δ _Wj ′ in the first embodiment is replaced with the flange clearance function δ instead of using the flange reduction function α. it is obtained so as to convert using _a.

In the second embodiment, the controller 3
Then, as shown in FIG. 8, in the first embodiment described above,
The processing of steps S6 and S7 in FIG.
Based on the sectional shape data of the shaped steel and the straightening load P, the following (1
5) Calculate the clearance of the flange, that is, the flange pressure.
Flange clearance function δ that represents the difference between the amount of roll reduction and the amount of web reduction _a
And the calculation in step S11.
Derived flange clearance function δ_aAnd calculated in step S5
Amount of reduction given to the flange_Fj'And the following (1
6) is calculated and the web reduction amount δ_Wj′ To calculate
The above figure except that it is replaced with step S12
5 is executed, and the process corresponding to FIG. 5 is the same.
One step number is attached and its detailed explanation is omitted.
It

[0045]   δ_a= Δ_a(T_W, H, t_F, B, r, P) (15)   δ_wj′ ＝ δ_Fj′ + Δ_a                        ………… (16) According to this second embodiment, the above-described first embodiment
Web crack limit load P_CSo as not to exceed
Lu pitch L^*Since it is set, the roller straightener 2
Be sure to prevent web cracking in the midline
In addition to being able to do the
Suitable roll pitch L^*And elastic limit curvature κ _y'And preset
Pitch in basic rolling pattern of basic H-shaped steel
L₀And elastic limit curvature κ_y0Of roller straightener based on
Each straightening roll R according to the rule of similarity_jApplied to the flange of
Lower amount δ_Fi′ Is decided, so deformed shoes on the roller straightener 2
History is almost the same as the deformation history of the basic H-section steel shown in Fig. 3,
Stable warpage against H-section steel of any steel type and cross-sectional shape
Correction is possible.

Thereafter, the reduction applied to the calculated flange
Quantity δ_FjSectional data of H-section steel for straightening and straightening
Flange clearance function that represents the clearance of the flange based on the load P
Number δ _aWeb reduction amount δ_Wj′ Is calculated, so
Reduction amount given to flange δ_Fi′ To web reduction δ_Wj′
The conversion to is accurate and easy, and more stable warping
You can do positive.

Standard size using this second embodiment
H300 × 300 × 10/15 (σ _y= 30 kg / mm²) And
And H900 x 300 x 16/28 (σ_y= 30 kg / mm²)
Of the amount of warp before and after straightening of H-shaped steel
The results are shown in Fig. 9. Basic rolling pattern used at this time
Used the basic rolling-down pattern shown in FIG.

During the straightening of these H-section steels, no web cracking occurred at all, and the warp amount after straightening was -20 m as shown in FIG.
Even if there are variations within the range of m to +20 mm, the warpage amount after straightening for all H-section steels with different yield stresses is all within the allowable range of -4 mm to +4 mm, and good straightening results can be obtained. It was

In the first and second embodiments, the case where the roller straightening machine 2 has nine straightening rolls has been described, but the number of straightening rolls is not limited to this, and any number of straightening rolls may be used. It goes without saying that the present invention can also be applied to a roller straightening machine that has it.

[0050]

[0051]

As described above , according to the invention of claim 1 , the optimum roll pitch is obtained from the limit of occurrence of web cracking, the pitch of the straightening roll is set, and then the set roll pitch and the straightening roll are set. The amount of reduction given to the flange is determined based on the basic reduction pattern of each straightening roll set so that the amount of warp is zero, and the amount of web reduction corresponding to the determined amount of reduction given to the flange is corrected by the straightening load and straightening. It was determined using the ratio of the web and flanges of the reduction rate determined from the cross-sectional shape of H-section steel of the subject, since to carry out the reduction control of the straightening rolls at the determined web rolling reduction, c
Roll pitch is set so as not to exceed the web breaking limit load
The web splitting is performed during straightening with a roller straightening machine.
It is possible to prevent this from happening without fail.
The optimum roll pitch of the H-section steel to be straightened that has been set
Roller based on C and basic rolling pattern of basic H-section steel
It is given to the flange of each straightening roll according to the similarity rule of the straightening machine.
The amount of rolling reduction that will be
The shape history is almost the same as the deformation history of the basic H-section steel,
Operator dependent on steel grade and H-section steel
Stable warp correction is possible without
Reduction Correction Control System for Web Based on Web Cracking Critical Load
Since it is only necessary to determine the amount of reduction given to the flange,
It can be easily constructed. Further, there is an effect that the amount of reduction applied to the flange can be accurately and easily converted to the amount of web reduction, and more stable warp correction can be performed.

Further, according to the second aspect of the invention, the optimum roll pitch is obtained from the limit of occurrence of web cracking to set the pitch of the straightening roll, and then the set roll pitch and the amount of warp after straightening become zero. The amount of reduction to be applied to the flange is determined based on the basic reduction pattern of each straightening roll set as described above, and the amount of web reduction corresponding to the determined amount of reduction to be applied to the flange is the straightening load and the H-shaped steel to be straightened. Since it is determined based on the difference in the amount of reduction between the web and the flange, which is obtained from the cross-sectional shape and the straightening load, and the roll reduction control of the straightening roll is performed with the determined web reduction amount. The effect is that the amount of reduction applied to the flange can be accurately and easily converted to the amount of web reduction, and more stable warpage can be corrected.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a sectional shape of H-section steel.

FIG. 3 is an explanatory diagram showing a deformation history represented by a relationship between a curvature coefficient and a moment coefficient during correction.

FIG. 4 is an explanatory diagram showing a relationship between a curvature coefficient and a moment coefficient for explaining a decrease in a warp amount due to a first large bending with respect to an inward warp.

FIG. 5 is a flowchart showing an example of a correction processing procedure by a controller.

FIG. 6 is H corrected by the correction method of the first embodiment.
It is explanatory drawing which shows the amount of warpage of the shaped steel before and after straightening.

FIG. 7 is an explanatory view showing a basic rolling pattern used for straightening the H-section steel of FIG. 6.

FIG. 8 is a flowchart showing an example of a correction processing procedure in the controller showing the second embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a warp amount before and after straightening of the H-section steel straightened by the straightening method of the second embodiment.

[Explanation of symbols]

1 H-shaped steel 2 Roller straightening machine R _{1 to} R ₉ Straightening roll RP Roll pitch adjusting device PA _j Rolling down amount adjusting device 3 Controller

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21D 3/05

Claims (2)

(57) [Claims] 1. A roller straightening machine having a plurality of straightening rolls arranged at variable pitches for rolling down an H-section steel web.
In a roller straightening method for H-section steel in which elasto-plastic deformation is applied to a flange to perform straightening, the pitch of the straightening roll is set by obtaining an optimum roll pitch from the limit of occurrence of web cracking, and then the set roll pitch web warping amount after correction determines the reduction rate to be applied to the flanges on the basis of the basic pressure pattern of each straightening roll set so that the zero, corresponding to the reduction amount giving the determined flange and
From the cross-sectional shape of the H-section steel to be straightened,
Determined using the ratio of the web and flange reductions found
Then, the roll straightening method for H-section steel is characterized in that the straightening roll is controlled to be rolled down by the determined web rolling down amount. 2. A roller straightening machine, in which a plurality of straightening rolls are arranged with variable pitch, is used to straighten an H-shaped steel web by pressing the web of the H-shaped steel to impart elasto-plastic deformation to the flange. In the roller straightening method, the optimum roll pitch is obtained from the limit of occurrence of web cracking, the pitch of the straightening roll is set, and then the set roll pitch and the basic amount of each straightening roll set so that the amount of warp after straightening is zero. The amount of reduction applied to the flange is determined based on the reduction pattern, and the amount of reduction of the web corresponding to the determined amount of reduction applied to the flange is adjusted by the straightening load and the web and the flange obtained from the cross-sectional shape of the H-section steel to be corrected . A method for straightening a roller for H-section steel, which is determined on the basis of the difference in the amount of reduction, and the reduction control of the straightening roll is performed with the determined amount of web reduction.