JPH09122703A - Rolling method for wide flange shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deflection of perpendicularity by making the width of horizontal rolls of a universal finishing mill different in accordance with difference between the temps. which are respectively measured at fillets between flanges and a web. SOLUTION: After a wide flange shape is formed to a prescribed shape, temp. differences between the fillets where exist on four places in one cross section and the flanges are measured with thermometers provided in the vicinity of an edger mill. When the temp. differences are calculated, they are outputted to a roll-width setting device, the widths of upper and lower variable width horizontal rolls of the universal finishing mill are adjusted by a proper mechanism. In this way, deflection of perpendicularity is reduced hardly affecting the height of web and thickness of flange.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling H-section steel, and more particularly, to a method for rolling H-section steel capable of reducing the squareness deformation that occurs during hot rolling.

[0002]

2. Description of the Related Art Generally, hot rolling of H-section steel is carried out by using equipment which is a combination of a breakdown rolling mill, a rough universal rolling mill, an edger rolling mill and a finishing universal rolling mill. That is, for example, a beam blank is formed into a rough material by a breakdown rolling machine,
Then, by repeatedly performing rolling and forming with a rough universal rolling mill and an edger rolling mill, the product is finished to almost a predetermined size, and finally, the perpendicularity of the flange is adjusted with the finishing universal rolling mill to obtain a product.

However, during the rough universal rolling, the H-section steel is non-uniformly cooled due to the effects of the roll cooling water, the heat retaining effect on the transport table, etc., and as a result, the inner and outer surfaces of the flange and the root of the flange and the web (hereinafter referred to as fillet). ) And the like cause temperature differences in various places. In addition, the flange thickness may vary depending on the play of the rolling mill.

If finish universal rolling is performed in this state and reduction is performed by horizontal rolls, the amount of deformation of the fillet differs at each location, and thus the flange squareness is likely to be displaced.

This state is shown in FIGS. 1 (a) and 1 (b). In the figure, the H-section steel 14 composed of the web 10 and the flange 12 is
The upper and lower ends of the flange 12 are deviated by T, and this deviation amount T is referred to as a squareness deviation amount. Such deviation of squareness may occur in opposite directions as shown in FIG. 1 (a) or in the same direction as shown in FIG. 1 (b).

Conventionally, in Japanese Laid-Open Patent Publication No. 63-192517, etc.,
Although a straightening method for H-section steel in which the squareness deviation has once occurred has been proposed, a proposal that does not cause the squareness deviation itself, that is, the squareness deviation that occurs during rolling is as small as possible. I couldn't see it.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for rolling H-section steel capable of preventing the occurrence of squareness deviation.

[0008]

Then, as a result of various studies to achieve such a subject, as a result of the squareness deviation in the finish universal rolling of H-section steel, the main cause is the four fillets in one cross section. It was found that this is because the amount of deformation is different at each place when the material is rolled down by the horizontal roll, that is, because of the temperature difference.

That is, such deformation of the fillet is caused by unevenness of the heat retaining effect on the conveying table during reversible rolling in the rough universal rolling mill or by temperature differences between the fillets due to roll cooling water or the like. As a result, it was found that the amount of deformation is different in each place even during rolling, which results in the deviation of squareness. However, it is practically impossible to eliminate such temperature difference during rolling of H-section steel.

Therefore, focusing on the correlation between the reduction of the horizontal roll in the finish rolling stage and the rising of the flange by the vertical roll, an attempt is made to adjust the squareness deviation generated in the rough universal rolling stage, and the horizontal roll is adjusted. The present invention has been completed, knowing that there is a certain correlation between the difference between the widths of the upper and lower horizontal rolls and the deviation of the squareness of the flange when the roll widths of the above-mentioned rolls are made different by the upper and lower horizontal rolls.

Therefore, the gist of the present invention is to perform rough rolling forming on a rough steel slab provided with a web and a flange by a rough universal rolling mill and an edger rolling mill, and then rolling by using a finishing universal rolling mill. In the H-section rolling method for finishing, the horizontal roll width of the finishing universal rolling mill is adjusted according to the difference in temperature measured between the flange and the fillet of the web after rolling by the rough universal rolling mill and the edger rolling mill. A method for rolling H-section steel capable of adjusting the squareness deviation of a flange, characterized in that finish rolling is performed by providing a difference between upper and lower horizontal rolls.

That is, according to the present invention, an H-section steel which is subjected to finish rolling in one pass in the finishing universal rolling mill after being subjected to intermediate-stage rolling for performing multi-pass reversible rolling with a rough universal rolling mill and an edger rolling mill. In the rolling method, the squareness deviation of the flange characterized by adjusting the upper and lower horizontal rolls of the finishing universal mill to different widths based on the measured value of the fillet temperature installed near the rough universal mill or the edger rolling mill. Is a method for rolling H-section steel.

As described above, in the present invention, it is difficult to control the temperature difference between the fillet and the flange to be zero for each rolled steel strip. In order to make a difference and to make the extension in the longitudinal direction of the rolling and the extension in the width direction of the flange uniform at each place of the fillet, at least one horizontal roll of the finishing universal rolling mill uses a variable width roll to perform rolling with different widths up and down. .

In the present invention, known horizontal rolls may be used as the horizontal rolls of the finishing universal rolling mill, and there is no particular limitation as long as at least one of the upper and lower horizontal rolls has a variable width.

[0015]

As described above, according to the present invention, the main cause of the squareness deviation in the finish universal rolling of H-section steel is due to the non-uniformity of the temperature between each fillet and the flange. .

That is, FIGS. 2 (a) and 2 (b) are schematic views showing how the squareness deviation occurs when the temperature of the fillet is high or low. When the temperature of the fillet portion 20 is relatively higher than the temperature of the flange in one cross section as shown in Fig. 4, when universal rolling is performed, the fillet portion extends in the rolling longitudinal direction, while the temperature of the fillet portion is lower than that of the flange. The flange extends in the width direction. Therefore, a squareness deviation occurs.

FIG. 3 is a rolling process diagram for carrying out the present invention, in which a rolling mill is used to produce a crude billet and then repeatedly rolled in a rough rolling stage consisting of a combination of a rough universal rolling mill and an edger rolling mill. By doing so, H-shaped steel having a predetermined shape is formed. The temperature deviation from the flange of the fillet at four locations on one cross section was measured by a thermometer provided near the edger rolling machine after being formed into a predetermined shape in this way, and if the temperature deviation was found, The amount of rolling width of the upper and lower horizontal rolls of the finishing universal rolling mill is changed accordingly.

FIG. 4 is a schematic explanatory view showing the relationship between them, and the temperature difference at each site is calculated from the measurement data obtained by the thermometer. The temperature difference is that of the fillet and its nearby flange. When such a temperature difference is calculated, it is output to the roll width setting device, and the width of the vertical width variable horizontal roll of the finishing universal mill is adjusted by an appropriate mechanism. Although the web height is usually constant in the finish universal rolling mill, it is obvious that the present invention is similarly applied to the case of adjusting the web height.

The difference in rolling width between the upper and lower horizontal rolls at this time is determined as follows. First, the correlation between the temperature difference between the fillet and the flange obtained as described above and the resulting deviation of the perpendicularity of the flange is obtained. The squareness deviation, which is measured by this, is predicted from the temperature difference.

On the other hand, as shown in FIG. 5, which will be described later, on the other hand, the relationship between the difference between the upper and lower horizontal roll widths and the flange squareness is obtained in advance so as to cancel the squareness deviation predicted as described above. Therefore, a sufficient difference between the upper and lower roll widths is obtained.

Then, the difference between the widths of the upper and lower rolls thus obtained is set in the upper and lower horizontal rolls of the finishing universal rolling mill so as to be symmetrical. Of course, if you change the width of the horizontal roll of the finishing universal rolling mill, the height of the web will also change, so adjust the width of either the upper or lower horizontal roll to such a predetermined dimension, Is changed by adjusting the width of the other horizontal roll. If the web height is not changed, the width of one of the horizontal rolls may be constant.

The mechanism for changing the squareness deviation by providing the rolling width of the upper and lower horizontal rolls will be described below. As shown in FIG. 6, the x-, y-, and z-axis coordinates are set, and it is presumed that flange raising rolling (without flange thickness reduction) is performed in UF (finishing) rolling, and rolling is performed only near the fillet.

At this time, the elongation in the z-axis direction is the elongation in the rolling longitudinal direction, which is the same in the vertical direction. That is, the z-axis upper extension amount = z-axis lower extension amount. Also, x
In the axial direction, the elongation is 0 due to being constrained by the horizontal rolls and the vertical rolls and the bilateral symmetry. That is, the x-axis upper extension amount = x-axis lower extension amount.

Therefore, the difference in the amount of reduction between the upper and lower fillet portions is the difference in the elongation in the y-axis direction. For example, if the fillet reduction amount is set as upper roll> lower roll as shown in Fig. 7, and there is a temperature difference in the flanges near the upper and lower fillets, there is a difference in the upper and lower deformation resistance as shown in Fig. 8 (a). Occurs, and as shown in FIG. 8 (b), relative elongation occurs in the y-axis direction, resulting in squareness deformation. Therefore, when the deformation resistance is large, that is, when the temperature is low, the y-axis elongation is small.

Here, if a difference is provided in the rolling width of the upper and lower horizontal rolls and the amount of fillet reduction is set as upper roll> lower roll, a difference occurs in the upper and lower deformation resistances as shown in FIG. 8 (a). Elongation occurs in the y-axis direction, resulting in rectangular deformation as shown in FIG. 8 (b). Therefore, by providing the difference in the rolling width of the horizontal rolls in this way, the elongation in the y-axis direction can be offset. Now, the present invention will be described in more detail with reference to its embodiments.

[0026]

[Example] In this example, the web height is 600 mm and the flange width is 30 mm.
The present invention was applied to the rolling of H-section steel of 0 mm (nominal size), and variable width rolls were applied to the upper and lower horizontal rolls of the finishing universal rolling mill, and the vertical width was changed. The results are shown in the graph in FIG. The temperature difference between the fillet and the flange at this time was measured by scanning the outer surface of the flange with a thermometer and was as shown in FIG.

Next, the H-section rolling method according to the present invention was applied to H-sections having the dimensions shown in Table 1, and the occurrence of squareness deviation at that time was investigated. The results are shown in Table 1 in comparison with the case of rolling in the conventional example (when the rolling method according to the present invention is not applied). The figures in the table are standard deviations of squareness.
(σ).

[0028]

[Table 1]

When the upper and lower horizontal rolls of the finishing universal rolling mill are made to have different rolling widths in actual operation, there is concern that the thickness of the flange may be different. Rolling that causes a taper does not affect the difference in flange thickness. It was also confirmed that the predetermined height could be obtained by setting the width difference between the upper and lower horizontal rolls within 1 mm in the web height. These relationships are summarized in FIG. 10 for the web height and in Table 2 for the flange thickness.

[0030]

[Table 2]

[0031]

EFFECTS OF THE INVENTION The present invention is configured as described above, and therefore, in finish universal rolling of H-section steel,
The squareness deviation can be significantly reduced with little influence on the web height and the flange thickness, which is extremely beneficial in the industry.

[Brief description of the drawings]

FIG. 1A and FIG. 1B are schematic explanatory diagrams of flange squareness deviation.

2 (a) and 2 (b) are schematic explanatory views of a mechanism for generating a squareness deviation of a fillet portion that occurs during finish universal rolling.

FIG. 3 is a process drawing showing an example of an H-section steel production line according to the present invention.

FIG. 4 is a schematic explanatory diagram of a rolling apparatus according to an embodiment of the present invention.

FIG. 5 is a graph showing the relationship between upper and lower different width roll rolling and flange perpendicularity.

FIG. 6 is a graph showing the relationship between upper and lower horizontal rolls of different width rolling and web height.

FIG. 7 is an explanatory diagram in which the amount of fillet reduction is set to upper roll> lower roll.

FIG. 8 (a) shows a difference between upper and lower deformation resistances.
(b) is an explanatory diagram in which elongation occurs in the y-axis direction and squareness deformation occurs.

FIG. 9 is a graph obtained by scanning the outer surface of the flange with a thermometer.

FIG. 10 is a graph showing a relationship between a web height and a vertical roll width difference.

Claims (1)

[Claims] 1. A rolling method for H-section steel, comprising: rough-rolling and shaping a rough-shaped billet having a web and a flange by means of a rough universal rolling mill and an edger rolling mill, and then finishing rolling by using a finishing universal rolling mill. After completion of rolling by the rough universal rolling mill and the edger rolling mill, the horizontal width of the finishing universal rolling mill has a difference between the upper and lower horizontal rolls according to the difference in temperature measured between the flange and the fillet of the web. A method for rolling H-section steel capable of adjusting squareness deviation of a flange, characterized by performing finish rolling by rolling.