JP6569691B2 - Manufacturing method of unequal side unequal thickness angle steel - Google Patents

Description

  The present invention relates to a method for producing unequal side unequal thick angle steel.

  As a method for controlling the bending and warping generated during cooling in the manufacturing process of conventional unequal side unequal thick angle steel, there is a method of controlling the amount of heat shrinkage by separately cooling the short side and the long side. (For example, refer to Patent Document 1). In addition, unequal side unequal thickness angle steel has an asymmetrical cross-sectional shape, and the rolling ratio varies depending on the rolling site, resulting in a difference in the amount of stretching, so warping and bending occur during rolling other than during cooling. A conveyance defect or quality defect occurs. Such warpage and bending can be controlled by adding restraint or correction with a guide attached to the rolling mill (for example, see Patent Documents 2 and 3).

In the above-mentioned Patent Document 1, cooling is controlled so that the short side is not less than Ar ₃ temperature and the long side is not more than Ar ₁ temperature before finish rolling, and the transformation expansion generated during cooling after finish rolling is used. It is said that bending can be suppressed by suppressing the difference in heat shrinkage between the two sides. However, depending on the specifications of the product, there are some that cannot be rolled in such a temperature range, so the applicable range is limited. In addition, no countermeasures against shape defects due to temperature non-uniformity in the longitudinal direction are shown, and in order to eliminate the shape defects, a load of correction by offline press processing (hereinafter simply referred to as press correction) is applied. There was a problem that.

  On the other hand, in the above-mentioned Patent Document 2, a shape steel having excellent bending and dimensional accuracy is manufactured by measuring the shape during rolling and before and after straightening and optimizing the setting of the rolling mill exit side restraint guide and straightening machine. The method is shown. And the adjustment of the rolling mill exit side restraint guide is effective in suppressing local bending of the longitudinal end, and the overall bending can be suppressed by optimizing the setting of the straightening machine using the result of shape measurement. . However, the technique described in this document is intended for high cross-sectional symmetry such as H-shaped steel, I-shaped steel, and groove-shaped steel manufactured by universal rolling, and the unequal sides with asymmetrical cross-sectional shapes. Unequal thick angle steel is not included. H-shaped steel, I-shaped steel, and grooved steel can be repeatedly bent back and forth with two straightening machines in the vertical and horizontal directions, making it easy to control the shape with the straightening machine. With an asymmetric unequal unequal thickness steel, it is difficult to suppress bending and the like only by optimizing the setting of the straightening machine.

  Also, in the above-mentioned Patent Document 3, a method of controlling the bending by the same technique is shown, and the object is an unequal angle iron or a rail having an asymmetric cross-sectional shape. These steel products have non-uniform rolling reduction ratios in the width direction, so the material to be rolled may be warped or bent, leading to poor conveyance. It is said that the transportability during rolling can be improved by adjusting this. In the technique described in this document, the bending amount can be controlled by obtaining the amount of bending from the rolling deformation prediction model and setting the optimum values of the rolling conditions and the position of the side guide. This rolling deformation prediction model is configured on the basis of measured values such as set values relating to rolling conditions, rolling roll intervals, rotation speeds, and side guide positions. The method described in this document can be applied to a section steel having an asymmetrical cross-sectional shape, and improves the transportability during rolling and enables the uniform longitudinal shape.

JP-A 51-96722 JP-A-9-174159 JP 2003-39107 A

  However, the technique described in Patent Document 3 described above is intended to avoid troubles such as poor conveyance during rolling by adjusting the shape during rolling. In other words, unlike the present invention, the technique described in Patent Document 3 is not intended for the final product shape. It cannot be said that it is sufficiently mitigated. For this reason, further improvement was calculated | required as a technique which manufactures an unequal side unequal thickness angle steel which has a desired shape efficiently and with high precision.

  An object of this invention is to provide the technique which manufactures the non-equal-side unequal thickness angle steel which has a desired shape efficiently and with high precision.

[1] A manufacturing method for manufacturing unequal side unequal thick angle steel by carrying out multi-stage rolling including finish rolling,
Based on the temperature distribution of the material to be rolled, the shape of the material to be rolled that has been finish-rolled, and the initial amount of bending deformation performed after finish rolling on the material to be rolled, A shape prediction step for predicting a shape at room temperature;
Based on the shape at room temperature predicted in the shape prediction step, the bending deformation adjustment step of adjusting the bending deformation amount of the material to be rolled,
Based on the bending deformation amount adjusted in the bending deformation amount adjusting step, a bending deformation applying step for applying bending to the material to be rolled after finish rolling;
A shape measuring step for measuring the shape of the material to be rolled after the bending deformation is applied;
A correction step of correcting the material to be rolled when it is determined that correction is required for the material to be rolled obtained after applying the bending deformation;
A manufacturing method of unequal sides and unequal thickness irons.
[2] Based on the shape of the material to be rolled measured after the bending deformation applying step, the amount of bending deformation performed after finish rolling of the unequal side unequal thick angle steel manufactured next to the material to be rolled. Next material bending deformation adjustment process to adjust,
The method for producing an unequal side unequal thick angle steel according to the above [1].
[3] The method for producing an unequal side unequal thick angle steel according to [1] or [2], wherein the temperature distribution of the material to be rolled is a temperature distribution of the material to be rolled before the finish rolling.
[4] The unequal side unequal thickness mountain shape according to [1] or [2], wherein the temperature distribution of the material to be rolled is the temperature distribution of the material to be rolled after the finish rolling and before the bending deformation applying step. Steel manufacturing method.
[5] The temperature distribution of the material to be rolled used in the shape prediction step is the temperature distribution on both the short side and the long side of the material to be rolled, according to any one of [1] to [4]. Method for producing unequal sides and unequal thickness irons.
[6] A cooling step of adjusting the temperature distribution of the material to be rolled by cooling the material to be rolled before the finish rolling,
The method for producing an unequal side unequal thick angle steel according to any one of the above [1] to [5].

  ADVANTAGE OF THE INVENTION According to this invention, the technique which manufactures the unequal-side unequal thickness angle steel which has a desired shape efficiently and with high precision is provided.

It is a figure which shows an example of the shape of the unequal side unequal thick angle steel which this invention makes object. It is the graph which showed typically the relationship between the transformation point which generate | occur | produces in the continuous cooling process of carbon steel, and elongation (length). It is a figure which shows the example of the unequal side unequal thick angle steel with a favorable shape, and the example of the unequal side unequal thick angle steel with a poor shape after correction. An example of the structure of the control system used with the manufacturing method of the unequal side unequal thickness angle steel of this invention is shown. It is a flowchart of the manufacturing method of the unequal side unequal thickness angle steel of this invention. It is a flowchart of the manufacturing method of the unequal side unequal thickness angle steel of this invention. It is a flowchart of the manufacturing method of the unequal side unequal thickness angle steel of this invention. It is a flowchart of the manufacturing method of the unequal side unequal thickness angle steel of this invention. It is a figure for demonstrating the method of calculating a curvature from the temperature measurement immediately after finish rolling, and the shape measurement after standing_to_cool. It is a correlation diagram of the curvature obtained by the difference of the shrinkage to the normal temperature of the short side and long side which are calculated | required using the temperature measured immediately after finishing rolling, and the shape measurement after standing_to_cool. It is an example of a structure of the bending provision apparatus used with the manufacturing method of the unequal side unequal thickness angle steel of this invention. The result of applying the control system in the present invention to an actual manufacturing process is shown.

  Hereinafter, the manufacturing method of the unequal side unequal thickness angle steel of this invention is demonstrated, referring drawings.

  FIG. 1 shows an example of the shape of an unequal side unequal thick angle steel targeted by the present invention. More specifically, in FIG. 1, the posture during rolling / conveying of unequal side unequal thick angle steel is shown in a perspective view and an XY plane cross-sectional view. As shown in FIG. 1, an unequal side unequal thick angle steel has an asymmetric cross section consisting of two sides with different lengths and thicknesses (hereinafter referred to as long sides and short sides), and after the end of rolling. Since the thick part is harder to cool than the thin part, the temperature at which air cooling starts is different.

  FIG. 2 is a graph schematically showing the relationship between the transformation point generated in the continuous cooling process of carbon steel and the elongation (length). In an unequal side unequal thick angle steel having a short side and a long side, a difference occurs in the amount of heat shrinkage between the short side and the long side, and warping and bending occur when cooling is completed. In particular, due to the difference in heat shrinkage between the short side and the long side, bending in the left-right direction (X-axis positive / negative direction in FIG. 1) is likely to occur.

  For this bending or the like, correction is generally performed by repeatedly applying bending back using a multistage straightening machine (hereinafter also referred to as a roller straightening machine) after the cooling is completed. However, the roller straightening machine can only bend in one direction, and it is difficult to bend in the right and left direction with high rigidity. It is difficult to correct with just one. Furthermore, even when there is a distribution in the amount of bending in the longitudinal direction, it is difficult to correct with a roller straightener alone. As described above, it is difficult to correct the unequal side unequal thickness iron with only the roller straightening machine for the correction of uneven warping and bending.

  FIG. 3 is a diagram illustrating an example of an unequal side unequal thick angle steel having a good shape and an example of an unequal side unequal thickness iron having a poor shape after correction.

  A shape defect as shown in FIG. 3 may remain in the unequal side unequal thick angle steel after correction by a roller straightener. For such shape defects remaining after correction, offline press correction is performed, which is one of the factors that hinder the increase in cost and the improvement of production efficiency.

  For such problems, the present inventors considered the relationship between the temperature distribution during finish rolling and the final shape, i.e., the shape cooled to room temperature, in the production of unequal side unequal thick angle steel. The present invention has been completed.

  The method for producing an unequal side unequal thick angle steel of the present invention is a production method for producing an unequal side unequal thick angle steel by carrying out multiple stages of rolling including finish rolling, and the temperature distribution of the material to be rolled, A shape prediction step for predicting the shape of the unequal side unequal thick angle steel at room temperature based on the shape of the finish-rolled material and the initial amount of bending deformation performed after finish rolling on the material. The bending deformation amount adjusting step for adjusting the bending deformation amount of the material to be rolled based on the shape at room temperature predicted in the shape prediction step, and the material to be rolled based on the bending deformation amount adjusted in the bending deformation amount adjusting step A bending deformation imparting step of imparting a bend after finish rolling.

  Further, in the present invention, based on the shape of the material to be rolled measured after the bending deformation applying step, the amount of bending deformation performed after finish rolling of the unequal side unequal thick angle steel manufactured next to the material to be rolled is calculated. You may include the adjustment process of the amount of bending deformation of the next material to adjust.

  Moreover, in this invention, the cooling process of adjusting the temperature distribution of a to-be-rolled material may be included by cooling a to-be-rolled material before finish rolling.

  Moreover, in this invention, the correction process which corrects the shape of the to-be-rolled material obtained after bending deformation provision may be included.

  The temperature distribution of the material to be rolled may be the temperature distribution of the material to be rolled before finish rolling, or the temperature distribution of the material to be rolled after finish rolling and before the bending deformation applying step. Moreover, it is preferable that the temperature distribution of the to-be-rolled material used at said shape prediction process shall be the temperature distribution of both the short side and long side of a to-be-rolled material.

  FIG. 4 shows an example of the configuration of a control system used in the method for manufacturing an unequal side unequal thick angle steel of the present invention.

  In FIG. 4, reference numeral 1 denotes a finish rolling mill for finish-rolling a rolled material (not shown) conveyed on the rolled material conveyance line X, and reference numeral 2 denotes a bending deformation applying step. Shows a bending applying device (for example, a guide device having a side guide) for applying a predetermined bending deformation amount. About this bending | flexion provision apparatus 2, in this invention, with reference to the adjusted bending deformation amount, by setting the pushing amount of the side guide (for example, side guide with a roller) installed in the exit side of the finishing mill 1, , Curb after correction.

  Reference numeral 3 denotes a thermometer that measures the temperature distribution of the material to be rolled on the entry side and the exit side of the finish rolling mill 1, and reference numeral 4 denotes a bending after the bending by the bending applying device 2 and before correction by the straightening machine. The shape meter which measures the shape of a to-be-rolled material is shown. Moreover, the code | symbol 5 shows the straightening machine (for example, roller straightening machine) which corrects the to-be-rolled material after bending deformation provision.

  Moreover, the code | symbol 6 shows the process computer which implements each control in manufacture of the unequal side unequal thickness angle steel of this invention. In particular, reference numeral 7 denotes a control unit that mainly performs each control in the above-described shape prediction step, bending deformation amount adjustment step, and next material bending deformation amount adjustment step. In the process computer 6, the temperature of the material to be rolled measured on the entry side of the finishing mill 1 may be taken in and processed. The shape meter 4 may be installed on either the entry side or the exit side of the straightening machine 5, and the shape measurement result is stored and statistically processed in the process computer 6 to provide feedback control and learning control. May be implemented.

  Hereinafter, with reference to FIG. 5 (FIGS. 5-1, 5-2, 5-3, and 5-4), the above-described shape prediction step, bending deformation amount adjusting step, bending deformation applying step, and next material bending The deformation adjustment process, the cooling process, and the correction process will be described.

  In the method for producing unequal side unequal thick angle steel according to the present invention, rolling in a plurality of stages including finish rolling as final rolling is performed. As rolling before finish rolling, rough rolling or one or more intermediate rollings can be performed. The Start stage in FIG. 5A is a stage in which the rolling immediately before the finish rolling is completed (the same applies to FIGS. 5-2, 5-3, and 5-4).

  The material to be rolled that has been rolled immediately before finish rolling is conveyed to the finish rolling mill 1 and subjected to finish rolling (step S2). The bending or the like of the material to be rolled that has occurred up to the entry side of finish rolling is generally corrected once by finish rolling.

<Shape prediction process>
In the shape prediction step in the manufacturing method of the unequal side unequal thick angle steel of the present invention, the temperature distribution of the material to be rolled, the shape of the material to be rolled on the finish rolling finish side, and the initial bending deformation of the material to be rolled Based on the amount, the shape of the unequal side unequal thick angle steel at room temperature after the bending deformation is applied is predicted (step S3).

  Then, after finish rolling (step S2), in the shape prediction step, the shape of the target unequal side unequal thickness steel is predicted at room temperature (step S3), and whether or not this shape is a desired shape. Determine (step S4). As described above, the shape of the unequal side unequal thickness angle steel at room temperature is predicted based on the temperature distribution of the material to be rolled, the shape of the material to be rolled after finish rolling, and the initial set amount of bending deformation of the material to be rolled. The

  The temperature distribution of the material to be rolled may be measured by the thermometer 3. The temperature distribution of the material to be rolled may be the temperature distribution of the material to be rolled before finish rolling, for example, the temperature distribution of the material to be rolled after the end of rolling immediately before finish rolling, or after bending and imparting bending deformation. It may be the temperature distribution of the material to be rolled before the process.

  The shape of the material to be rolled after finish rolling may be optically measured using a laser or the like after the finish rolling, or may be estimated in advance from finish rolling conditions or the like.

  The initial set amount of bending deformation of the material to be rolled can be set based on the amount of bending deformation adjusted with respect to the material to be rolled manufactured in advance. When the target material to be rolled has the same steel type and shape as the preceding material to be rolled, the bending deformation adjusted for the previous material to be rolled is used as the initial bending deformation of the material to be rolled. If the target material to be rolled is different in steel type and shape from the preceding material to be rolled, the material to be rolled is based on the amount of bending deformation adjusted to the previous material to be rolled. The initial set amount of bending deformation may be changed as appropriate. Moreover, you may consider the shape of the bending provision apparatuses 2, such as a guide apparatus which has a side guide, for the bending deformation initial setting amount of a to-be-rolled material.

  The details of the shape prediction at room temperature based on the temperature distribution of the material to be rolled, the shape of the material to be rolled after finish rolling, and the initial set amount of bending deformation of the material to be rolled should be based on a thermal deformation prediction model. This thermal deformation prediction model will be described later.

<Bending deformation adjustment process>
In the bending deformation amount adjustment step, the bending deformation amount of the material to be rolled is adjusted based on the shape predicted in the shape prediction step.

  More specifically, in this step, first, it is determined whether or not the shape of the unequal side unequal thick angle steel predicted in the shape prediction step is a desired shape (step S4). The desired shape can be appropriately set such as the shape of the unequal side unequal thick angle steel to be finally obtained, that is, the shape straight in the longitudinal direction, the shape having a uniform curvature, etc., depending on the shape at room temperature. it can.

  When the shape predicted in step S4 is a desired shape, the bending deformation amount is not changed, and based on this bending deformation amount, bending deformation is imparted to the material to be rolled in the next process ( Step S6). On the other hand, if the predicted shape is not the desired shape, the bending deformation amount is changed (step S5). The change amount of the bending deformation amount can be changed with reference to the database (storage unit in the control unit 7) 71. The database 71 includes past results on the relationship between the temperature distribution of the material to be rolled, the shape of the material to be rolled after finish rolling, the amount of bending deformation imparted to the material to be rolled, and the shape at room temperature that is predicted. A value is stored. Based on the past actual values, a relationship between the predicted shape at room temperature and the amount of bending deformation necessary to keep the predicted shape at room temperature within an allowable range is required. Therefore, by referring to this database 71, the change amount of the bending deformation amount can be determined to an appropriate value according to the difference between the predicted shape at room temperature and the desired shape. The changed bending deformation amount can be stored in the database 71. Based on the changed amount of deformation, bending deformation is imparted to the material to be rolled in the next step (step S6).

<Bending deformation imparting process>
Next, in the bending deformation applying process, bending is applied to the material to be rolled after finish rolling based on the bending deformation adjusted in the bending deformation adjusting process (step S6). More specifically, in this step, a predetermined amount of bending deformation is imparted to the material to be rolled by adjusting the push-in amount with a bending imparting device (for example, a guide device having a side guide) 2.

  At this time, it is preferable that this bending deformation is applied based on a thermal deformation prediction model, and it is preferable to apply bending according to the result calculated by this model to the material to be rolled.

  As described above, since the bending deformation is applied after the amount of bending deformation is appropriately adjusted, it is possible to reduce the load of correction processing in the correction process described later. And since the shape defect after a straightening process is also suppressed, the load of off-line press straightening is also reduced, and an unequal side uneven thickness steel can be manufactured efficiently and highly accurately.

<Shape measurement process>
Subsequently, the shape of the material to be rolled to which bending deformation is applied is measured by a shape meter (not shown) (step S7). The shape measurement of the material to be rolled to which bending deformation is applied is preferably performed after the temperature of the material to be rolled has cooled to near room temperature. Therefore, for example, in the production line of unequal side unequal thickness steel, when a cooling bed is interposed from the rolling line to the finishing line, it is preferable to provide a shape meter on the exit side of the cooling bed or further downstream thereof.

<Correction process>
In the present invention, in the straightening process, when it is determined that the material to be rolled obtained after the bending deformation needs to be straightened, the material to be rolled is straightened so as to have a desired shape (step S10). In particular, when it is determined in step S7 that the shape of the material to be rolled is not a desired shape, it is preferable to correct the material to be rolled to a desired shape in this step. In this step, the material to be rolled can be corrected using a correction machine (not shown) such as a roller correction machine.

  As described above, according to the present invention, the unequal side unequal thick angle steel can be efficiently and accurately manufactured. In addition, after the above straightening step, processing of the unequal side unequal thick angle steel may be performed as appropriate.

<Next material bending deformation adjustment process>
In the present invention, based on the shape of the rolled material measured after the bending deformation applying step, a next material bending deformation adjusting step for adjusting the bending deformation amount of the rolled material to which bending is applied next to the rolled material. (See FIG. 5-2).

  More specifically, first, the shape of the material to be rolled with bending deformation is measured by a shape meter (not shown) (step S7). Next, it is determined whether or not the shape of the material to be rolled measured by a shape meter (not shown) is a desired shape (step S8).

  When the actually measured shape is a desired shape, the bending deformation amount is not changed for the next non-equal-sided unequal thickness steel, and this bending deformation amount is manufactured next. The initial set amount of bending deformation of the unequal side unequal thick angle steel. On the other hand, if the measured shape is not the desired shape, the bending deformation amount is a predetermined amount so that the desired shape can be obtained based on the relationship between the bending deformation initial setting amount obtained in advance and the shape near room temperature. The amount of bending deformation thus changed is set as the initial amount of bending deformation of the unequal side unequal thick angle steel to be manufactured next (step S9). The bending deformation amount to be changed can be changed with reference to the database (storage unit in the control unit 7) 71, and the changed bending deformation amount can be stored in the database 71.

  Thus, by adjusting the amount of bending deformation of the next material of the material to be rolled, it is possible to more efficiently manufacture the unequal side unequal thick angle steel of the next material.

<Cooling process>
In the present invention, the material to be rolled is subjected to finish rolling (step S2) before the shape prediction of the unequal side unequal thick angle steel in the shape prediction step (step S3). As shown in FIG. 5-3, a cooling step may be provided before this finish rolling (step S1).

  In the cooling step, for the purpose of adjusting the temperature distribution of the material to be rolled on the exit side of the finish rolling mill 1, the material to be rolled can be cooled using a cooling device (not shown). The cooling conditions at the time of cooling are the manufacturing condition data for the material to be rolled in advance and the shape data measured at room temperature, and a database (in the control unit 7) storing appropriate cooling conditions corresponding to these data. It is adjusted with reference to the storage unit). Thereby, since the time required for the material to be rolled to cool to the preset finish rolling temperature is shortened, the rolling efficiency can be improved.

  Further, as shown in FIG. 5-4, even when this cooling step is provided, the above-mentioned next-material bending deformation amount adjusting step can be provided. Thereby, manufacture of the unequal side unequal thick angle steel of the next material can be performed more efficiently.

(Thermal deformation prediction model)
As described above, it is preferable that the shape prediction in the shape prediction step in the method for manufacturing an unequal side unequal thick angle steel of the present invention is performed based on a thermal deformation prediction model. The present inventors have arranged the amount of bending in the left and right direction and the difference in thermal expansion with respect to the difference in thermal expansion between the long side and the short side that are the cause of the bending of the material to be rolled, and quantified the amount of bending in the left and right direction. . And before finishing rolling, based on the temperature measurement result of the short side and the long side, by setting the pushing amount so that the shape is corrected using the bending applying device (side guide) 2, the horizontal direction I devised a method to minimize the bending of.

  Below, the guide setting method which controls the bending of the left-right direction using a thermal deformation prediction model is demonstrated in detail.

  FIG. 6 is a diagram for explaining a method of calculating the curvature from the temperature measurement immediately after finish rolling and the shape measurement after cooling. FIG. 7 is a correlation diagram between the difference between the shrinkage ratios of the short side and the long side to room temperature obtained using the temperature measured immediately after finish rolling and the curvature obtained from the shape measurement after standing to cool.

  Based on FIG. 6 and FIG. 7, the outline of temperature measurement and shape measurement in the actual manufacturing process, and the relationship between the heat shrinkage rate difference between the short side and the long side resulting from cooling and the shape after cooling is completed. Will be explained.

The object to be measured is a small-section unequal unequal thickness angle steel with low rigidity in the left-right direction, which tends to bend (long side width A = 200 mm, long side thickness t ₁ = 9 mm, short side width B = 90 mm, short side Thickness t ₂ = 14 mm) (see FIG. 1).

  In obtaining the heat shrinkage difference, the temperature was obtained from the thermal image taken by thermography from the left and right directions with respect to the total length (about 100 m) in the rolling direction on the exit side of the finishing mill 1. Then, a value near the center of each side width is extracted from the temperature distribution in the width direction as the representative temperature of each side, the temperature distribution in the longitudinal direction of each side is obtained, and the short side of the thermal contraction rate due to cooling is determined from the thermal expansion curve. The difference at the long side was calculated.

  On the other hand, as a method for measuring the shape, a curved shape in the left-right direction was obtained by performing image processing on a moving image obtained by photographing a material to be rolled with a video camera on the roller correction machine 5 entry side. And the average curvature (kappa) was computed from the following formula | equation (1) on the assumption that the shape of each product was a quadratic function form from the result of shape measurement.

  In addition, as shown in FIG. 6, d is a curvature amount (mm), L is the length (mm) of an unequal side unequal thick angle steel.

  At this time, the material to be rolled is hot-sawed after finish rolling and has a length of about 10 to 25 m. As shown in FIG. 7, when the temperature difference between the short side temperature and the long side temperature immediately after finish rolling changes according to the manufacturing conditions (that is, when the difference in shrinkage rate changes), warping after the end of cooling is large. It can be seen that it changes (that is, the curvature changes greatly). It can also be seen that not only the change in the manufacturing conditions but also the temperature variation in the longitudinal direction of the material to be rolled causes a variation in the amount of bending and the shape becomes non-uniform.

  According to the present invention, the result of temperature measurement on the finish rolling delivery side is taken into the above-described thermal deformation prediction model to predict the amount of deformation, and the required amount is provided by the bending device 2 arranged on the delivery side of the finishing mill 1. By applying left and right bending, it becomes possible to prevent the occurrence of shape defects. In the present invention, the bending is controlled from the deformation prediction based on the temperature distribution on the finish rolling delivery side. Therefore, the material to be rolled is cooled, and the shape change due to thermal contraction does not occur, and the bending can be controlled before the final shape is determined. Further, the bending can be controlled without having to consider the influence of the transformation temperature.

  Here, it is preferable to measure the temperature distribution for each of the short side and the long side. Further, the temperature distribution measurement position may be between the finishing mill 1 and the bending device 2. On the other hand, it may be considered that the bending apparatus 2 and the finishing mill 1 are close to each other and it is difficult to secure a space for installing the thermometer 3 on the exit side of the finishing mill 1. In addition, when controlling the amount of bending deformation by feedforward from the temperature measurement result, it is considered that the time measurement for reflecting the prediction result in the control amount cannot be sufficiently secured in the temperature measurement on the delivery side of the finishing mill 1. It is done. In these cases, a method may be used in which temperature measurement is performed on the entry side of the finishing mill 1 to predict the temperature distribution on the exit side, and thermal deformation prediction is performed using the predicted value.

  Furthermore, in addition to the correlation equation in the actual machine as described above, the thermal deformation prediction model is a model that combines numerical analysis using an offline finite element method, etc., or a combination of the correlation equation in the actual machine and the result of the numerical analysis. May be used. And it is also possible to modify the prediction model and improve the accuracy of the control by continuing the shape measurement of the material to be rolled whose shape is controlled on the correction machine 5 entry side.

  Further, as described above, the right / left bending can be applied by using a bending applying device (side guide or guide roller) 2 having a mechanism capable of controlling the pushing amount in the left / right direction. The bending imparting device 2 preferably has a structure that is sandwiched from the left and right according to the width of the material to be rolled. In addition, it is preferable to have a structure that can bend in both directions of the short side and the long side.

Here, an example of the bending apparatus 2 will be described with reference to FIG. FIG. 8 is an example of a configuration of a bending imparting device used in the method for producing an unequal side unequal thick angle steel of the present invention. As shown in FIG. 8, a structure in which a pressing roller 21 with a variable pressing amount is added to the exit side of the side guide is suitable. Further, the left and right pushing amount of the bending imparting device 2 and the distance from the finish rolling mill 1 to the bending imparting device 2 are determined by the degree of curvature determined by the thermal deformation prediction model. For example, assuming that a bend of a quadratic function is applied by the bending applying device 2, the lateral displacement d (m) of the material to be rolled and the distance from the finish rolling mill 1 to the bending applying device 2 (more specifically, When the distance (l) between the center of the rolling roll 11 of the finishing mill 1 and the center of the pressing roller 21 of the bending imparting device 2) l (m) is used, the curvature κ (m ⁻¹ ) is expressed as shown in Expression (2). .

  However, the actual pushing amount of the bending imparting device 2 must be taken into account by the displacement amount d because the rigidity of the device 2 and the spring back of the material to be rolled must be taken into consideration. From equation (2), it can be seen that the smaller the distance l between the finishing mill 1 and the bend imparting device 2, the more the controllability is improved because the bending changes with a smaller amount of pushing. Furthermore, since it becomes difficult to control bending during traveling between the rolling rolls 11 at the front end and tail end of the material to be rolled and the bending applying device 2, the distance between the finish rolling mill 1 and the bending applying device 2 is as much as possible. It is desirable to make it smaller. In addition, when the distance between the roll bending apparatuses is large, the necessary push amount becomes very large, which may hinder the conveyance. Considering these, it is preferable that the bending apparatus 2 is installed within 10 m from the finishing mill 1 at the maximum. On the other hand, when the installation distance l is very small, the load required for pushing increases, so it is desirable to provide a distance of at least 1 m from the finishing mill 1.

  In the above, the manufacturing method of the unequal side unequal thick angle steel of this invention was demonstrated. ADVANTAGE OF THE INVENTION According to this invention, the technique which manufactures the unequal-side unequal thickness steel which has a desired shape efficiently and highly accurately is provided. More specifically, in the present invention, when producing an unequal side unequal thick angle steel having an asymmetric cross-sectional shape, the relationship between the temperature during finish rolling and the final shape is considered, that is, the rolling of the material to be rolled. The amount of warping or bending in the left-right direction that occurs after cooling is completed is predicted by a thermal deformation prediction model. Thereby, the position setting of a rolling guide is performed with high precision and efficiency, the effect which controls the bending which generate | occur | produces during cooling, and suppresses the shape defect after roller correction is acquired. Therefore, it is possible to suppress the need for offline press correction. As a result, correction with only a roller straightener is possible, and productivity can be improved.

  In addition, according to the present invention, it is possible to control the final longitudinal shape of the unequal side unequal thick angle steel without the need for cooling below the transformation point. It can be applied regardless of the required characteristics. Moreover, in the manufacturing method of this invention, since it is possible to control bending according to the temperature distribution in each position of a longitudinal direction, it can also suppress that a shape becomes non-uniform | heterogenous in a longitudinal direction.

Example 1
As an example of the present invention, the finishing mill 1 shown in FIGS. 4 and 8 is used to measure a long side width A = 200 mm, a long side thickness t ₁ = 9 mm, a short side width B = 90 mm, a short side thickness t ₂ = 14 mm, a pressure An unequal side unequal thick angle steel having an extension of about 100 m and a product length (length after sawing) of 20 m was produced (see also FIG. 1).

On the exit side of the finishing mill 1, a side guide with a roller having a mechanism for pushing the material to be rolled in the left-right direction as a bending imparting device 2 was disposed. This side guide was designed to bend both the short side and the long side so that the material to be rolled was sandwiched from both sides. The distance l from the center of the rolling roll 11 of the finishing mill 1 to the center of the pressing roller 21 was 1 m. In addition, after rolling, sawing and cooling are performed, and when the temperature reaches room temperature, correction is performed by the roller straightening machine 5, and if the left and right bend of the product is 25 mm or less in total length, the shipping standard is passed. If this is the curvature using the formula (1), the allowable curvature is 5 × 10 ⁻⁷ mm ^−1, and if it is larger than this curvature, offline press correction is required. The average temperature before entering the finishing mill 1 was about 740 ° C. on the short side and about 650 ° C. on the long side.

In this example, the temperature during rolling was determined by the finishing mill 1 by predicting the temperature change before and after rolling by installing a thermometer 3 that independently measures the short and long sides before and after the finishing mill 1. Furthermore, the bending caused by the temperature difference is considered to be 1.0 × 10 ⁻⁵ mm ^{−1 at the} maximum from the relationship between the temperature distribution obtained in advance and the shape at room temperature, and the control range of bending given by the guide is about the same. As a result of predicting the subsequent deformation amount by the above-described thermal deformation prediction model, the pushing amount of the guide 2 by the roller 21 was set to 15 mm at the maximum from the short side to the long side direction.

And when it rolled using the system of the manufacturing method of this invention, since the average curvature by the side of the straightening machine 5 became 2.5 * 10 <^-7> mm <^-1> , and it was an allowable bending amount, it was the subsequent press. No correction was necessary. On the other hand, as a comparative example, the average curvature on the exit side of the straightening machine 1 of the guide 2 that was not pushed by the roller 21 was 9.5 × 10 ⁻⁶ mm ⁻¹ , which was a bending amount that was more than the allowable limit. Therefore, press correction was necessary after that.

(Example 2)
Next, as Example 2, an example in which the effect of the present invention is confirmed for a plurality of materials to be rolled using the finish rolling mills of FIGS. 4 and 8 will be described. The steel piece has a long side width A = 200 mm, a long side thickness t ₁ = 9 mm, a short side width B = 90 mm, a short side thickness t ₂ = 14 mm, and a rolling length of about 100 m. As a result, it became the range of 660-680 degreeC in the short side, and 740-760 degreeC in the long side.

  FIG. 9 shows measurement results when the system of the manufacturing method of the present invention is not applied (round) and when applied (square) when rolling. The horizontal axis is the shrinkage difference obtained from the temperature distribution of the short side and the long side after finish rolling, and the vertical axis is the curvature at the entry side of the straightening machine 5. As described above, by using the method shown in the present invention, it is possible to appropriately control the shape after completion of cooling regardless of the production temperature condition, and to suppress the need for offline press correction.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

1 Finishing mill 2 Guide device (bending device)
3 Thermometer 4 Shape Meter 5 Roller Straightening Machine 6 Process Computer 7 Controller 71 Storage Unit

Claims (6)

It is a manufacturing method for manufacturing unequal side unequal thick angle steel by carrying out multi-stage rolling including finish rolling,
Based on the temperature distribution of the material to be rolled, the shape of the material to be rolled that has been finish-rolled, and the initial amount of bending deformation performed after finish rolling on the material to be rolled, A shape prediction step for predicting a shape at room temperature;
Based on the shape at room temperature predicted in the shape prediction step, the bending deformation adjustment step of adjusting the bending deformation amount of the material to be rolled,
Based on the bending deformation amount adjusted in the bending deformation amount adjusting step, a bending deformation applying step for applying bending to the material to be rolled after finish rolling;
A shape measuring step for measuring the shape of the material to be rolled after the bending deformation is applied;
A correction step of correcting the material to be rolled when it is determined that correction is required for the material to be rolled obtained after applying the bending deformation;
A manufacturing method of unequal sides and unequal thickness irons. Next, based on the shape of the material to be rolled measured after the bending deformation imparting step, the amount of bending deformation to be performed after finish rolling of the unequal side unequal thick angle steel manufactured next to the material to be rolled is adjusted. Material bending deformation adjustment process,
The manufacturing method of the unequal side unequal thickness angle steel of Claim 1 which further contains these.   The method for producing unequal side unequal thick angle steel according to claim 1 or 2, wherein the temperature distribution of the material to be rolled is a temperature distribution of the material to be rolled before the finish rolling.   The method for producing an unequal side unequal thick angle steel according to claim 1 or 2, wherein the temperature distribution of the material to be rolled is the temperature distribution of the material to be rolled after the finish rolling and before the bending deformation applying step.   The unequal side unequal thickness according to any one of claims 1 to 4, wherein the temperature distribution of the material to be rolled used in the shape prediction step is a temperature distribution on both the short side and the long side of the material to be rolled. A manufacturing method of angle steel. Cooling step of adjusting the temperature distribution of the material to be rolled by cooling the material to be rolled before the finish rolling,
The manufacturing method of an unequal side unequal thickness angle steel according to any one of claims 1 to 5.

Images