JPH04224011A - Method for rolling shape steel short of deviation of center of web - Google Patents

Abstract

PURPOSE:To obtain practical rolling method for shape steel having a flange short of deviation in a web center. CONSTITUTION:Three or more pairs of facing guide rollers 13-15 which can be adjusted to the vertical direction with an opening Cu are built in frictional guides 10. The opening Cu of the pairs of guide rollers 13-15 is made a value considerably approximate to the thickness (t) at the web part (beta) of the rolled steel 19 and the opening is set to be vertically equidistant from the pass line 7 being the center of vertical/horizontal rollers 4a, 4a'. The vertical bending of the rolled steel 19 is straightened by the guide roller 14 between the guide rollers 13, 15 on both sides. Since the rolled steel is always bitten into the vertical/horizontal rollers 4a, 4a' in a state agreeing to the pass line 7, a shape steel free from change of the web position by the vertical/horizontal rollers 4a, 4a', short of deviation of the center of the web and excellent in accuracy can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling method for reducing web center deviation when hot rolling a section steel having a flange using a universal mill.

0002

2. Description of the Related Art H-section steel and similar section steel are generally rolled using a universal mill. An example of this method is shown in Figs. 7(a) and (b). After roughly forming a shape similar to an H shape using a breakdown mill 1, a universal mill 2 having upper and lower horizontal rolls 2a and left and right vertical rolls 2b is used to stretch the web part A and flange part B, and to form the upper and lower edges. Sequential rolling is performed in combination with shaping of the flange tip C using an edger mill 3 having a jar roll 3a, and finally an H-beam steel is produced using a finishing universal mill 4 that shapes the steel into a predetermined shape.

[0003] In rolling with a universal mill group, a guide is attached to the mill in order to guide the rolled steel material to the mill. That is, as shown in FIG. 6(a), guides 2c and 2d of integral structure are provided on the entrance and exit sides of the universal mill 2, respectively.
In addition, as shown in FIG. 3(b), guides 3c and 3d are provided on the entrance and exit sides of the edger mill 3 as well. Since these guides are integrally structured friction guides, from the viewpoint of preventing friction scratches or poor biting due to restraint by the guide, the inner widths wu and we of the steel material and the steel material shown in Fig. 7(b) are Web thickness tu
, te, the width of the guide and the gaps cu, ce between the upper and lower guides shown in FIG. 6 are usually set as large as possible without causing any problems.

However, in the above-mentioned guide, a deviation between the web thickness center 5 and the flange width center 6, ie, web center deviation S, tends to occur as shown in FIG. 5 during rolling with a universal mill. This generation mechanism is
The case of rolling with the finishing universal mill 4 shown in FIG. 7 will be explained with reference to FIG. 4 as an example.

[0005] The upper and lower friction guides 10 arranged at the entrance side of the finishing universal mill 4, which consists of upper and lower horizontal rolls 4a, 4a' and left and right vertical rolls 4b, 4b', are arranged at the center of the upper and lower horizontal rolls 4a, 4a'. Even if the vertically equidistant cu/2 is set to the pass line 7, the entrance guide gap c is determined by the web thickness tu of the entrance rolled steel material.
Because u is large, the center of the web portion A of the input rolled steel material almost never coincides with the pass line 7, and as an example, it is highly conceivable that the web portion A may tilt and bite into the finishing universal mill 4 as shown in FIG.

On the other hand, in rolling with a universal mill, the amount of thickness reduction by the vertical rolls 4b, 4b' of the flange portion B is set to be larger than the amount of thickness reduction of the web portion A from the viewpoint of preventing rolling web waves. The amount of thickness reduction in A is divided into 1/2 between the upper and lower horizontal rolls 4a and 4a', but the amount of thickness reduction in flange portion B is rolled independently on the left and right sides, so the apparent amount of reduction in flange portion B is This is more than twice the amount of reduction in web portion A. As a result, it is generally known that the vertical roll biting start position 9 of the flange part B is located before the horizontal roll biting start position 8 of the web part A.

When the entrance steel material is inserted into the finishing universal mill 4 at an angle as shown in FIG. 4, the flange part B is shifted upward in the vertical direction and bites into the vertical rolls 4b and 4b', causing the vertical rolls to bite. It is fixed on the line of starting position 9. Immediately after that, the web part A is deformed by α to the line of the horizontal roll biting start position 8 by the upper horizontal roll 4a (referred to as a web position repositioning phenomenon), and the web center deviation S occurs in the rolled product.
(a state shifted by α) occurs.

[0008] As described above, the problem with conventional friction guides is that no matter how well they are set to match the pass line, the upper and lower guide gaps are larger than those of rolled steel, so they are hardly effective in preventing deterioration of the web center deviation. was there.

[0009] In order to solve this problem, a roller guide for H-beam steel has been considered. As an example, Unexamined Japanese Patent Publication No. 6
There is one described in Publication No. 3-36914. When rolling with a universal mill, the web part and the inner part of the flange of the rolled steel material are each supported at four points by two sets of horizontal and vertical guide rollers, and the gap between the rolled steel material and the guide is set precisely. By accurately guiding and rolling the roll into the roll hole mold, friction with the guide is prevented and products with high dimensional accuracy are manufactured. In addition, Japanese Patent Application Laid-Open No. 64-2715 discloses that in rolling with a universal mill, the tips of the upper and lower flanges of the rolled steel material are guided and rolled by a tapered guide roller while centering with the universal roll, thereby rolling the steel material into a web. It is disclosed that the invention aims to prevent friction scratches and improve dimensional accuracy.

0010

SUMMARY OF THE INVENTION In the above-mentioned prior art, some improvement effect can be found from the viewpoint of improving the web-centered bias, but the following problems remain.

The method described in JP-A-63-36914 has a difficulty in improving the web center deviation because the upper and lower surfaces of the web portion of the rolled steel material are held by two pairs of guide rollers. The reason for this will be explained with reference to FIG.

In order to compensate for the drawbacks of the integrated friction guide, two pairs of guide rollers 11, 1 are provided opposite to the entry friction guide 10 in universal rolling.
2 is arranged with the vertical gap aligned with the pass line 7, and even if the upper and lower surfaces of the web part A of the rolled steel material are precisely held and guided, the rolled steel material will have some vertical bending. Because of the presence of vertical warpage (also referred to as vertical warpage), it is not possible to always align the rolled steel material with the pass line and engage it in the universal mill as shown in Fig. 3. Therefore, as described above, in FIG. 3, the web position is changed by α' by the upper and lower horizontal rolls 4a, which tends to cause deviation S' in the center of the web after rolling, which is not sufficiently improved.

[0013] The method described in JP-A No. 64-2715 holds the top and bottom flanged tips of the rolled steel material and guides the rolled steel material while aligning them with the pass line, which causes a web center deviation in the steel material before universal rolling. what you are doing,
It is thought that the problem can be improved by changing the web position using universal rolling and correcting the web center deviation. Considering this mechanism, it is necessary to precisely maintain the flange width of the rolled steel material, but since the flange width varies considerably more than the web thickness, it is necessary to guide the flange width while rolling down the flange width with a tapered roller. problem occurs.

First, the taper roller is locally worn at a width corresponding to the thickness of the flange of the rolled steel material, and a stepped flaw occurs at the tip of the flange depending on the thickness size. In addition, local wear of the taper roller is rapid, requiring frequent replacement of the taper roller, which reduces rolling efficiency. Furthermore, it is difficult to set the gap between the tapered rollers precisely because of the rapid wear. moreover,
If the taper roller is not set very accurately with respect to the pass line, it is not practical to improve the web center deviation because it will have the opposite effect, and if the gap between the taper rollers is made coarser, the effect of improving the web center deviation cannot be expected.

The present invention solves these problems and provides a method for rolling a section steel having a flange, which is practical and causes less deviation from the center of the web.

[0016]

[Means for Solving the Problems] The gist of the present invention is to provide three or more pairs of facing upper and lower surfaces of the web portion of the rolled steel material in the entrance guide of the universal mill when hot rolling a section steel having a flange using a universal mill. This is a method of rolling a section steel with less deviation from the center of the web, which is characterized in that the web is guided and rolled while being held by guide rollers.

[0017]

[Operation] The present invention will be explained in detail below using H-beam steel as an example.

In the example of the mill layout shown in FIG. 7(a), after rough forming a shape similar to the H shape in the breakdown mill 1, a universal molding using rolls having a shape as shown in FIG. 7(b) is performed. When rolling is performed by a combination of the mill 2, edger mill 3, and finishing universal mill 4, a guide shown in FIG. 2 is provided on the entry side of the universal mill 2 and finishing universal mill 4 to guide and guide the rolled steel material 19. That is, a friction guide 10 attached to a universal mill has built-in three or more pairs (shown as an example of three pairs) of opposing guide rollers 13, 14, and 15 whose opening degree cu can be adjusted in the vertical direction. To manufacture an H-beam steel with less web center deviation over its entire length.

FIG. 1 is an explanatory diagram of a mechanism capable of producing an H-beam steel with less deviation in the center of the web, and is shown using an example of the finishing universal mill 4 shown in FIG. 7(a).

Three pairs of opposing guide rollers 13, 14, 15 are built into a friction guide 10 disposed on the entry side of the finishing universal mill 4, which consists of upper and lower horizontal rolls 4a, 4a' and left and right vertical rolls 4b, 4b'. The upper and lower surfaces of the web portion A of the rolled steel material 19 are held precisely. That is, the vertical clearance cu between the three pairs of guide rollers 13, 14, and 15 is set to a value (cu ≧tu) approximated by the thickness tu of the web portion A of the rolled steel material 19, and at the center of the upper and lower horizontal rolls 4a and 4a'. It is set to match the pass line 7 so that it is equidistant cu/2 in the vertical direction with respect to a certain pass line 7.

The two opposing pairs of guide rollers 11 and 12 shown in FIG. , 15 between the guide rollers 1
4, it is possible to correct vertical bending, and the greater the number of guide rollers in between, the better the correction effect. In this way, the web part A and the flange part B of the rolled steel material 19, whose vertical bends have been corrected, move to the vertical roll biting start position 9, then to the horizontal roll biting start position 8, with no deviation in the vertical direction. Even with sequential biting, the amount of web position change α″ is very small (α″≒0),
It is possible to obtain an H-beam steel with less web center deviation (S'').In addition, by aligning the rolled steel material 19 more closely with the pass line 7, the vertical rolls 4b, 4b', the upper and lower horizontal rolls 4a, 4a
′, in order to avoid misalignment with the pass line 7 when there is a slight vertical bend between the guide roller 13 on the roll side and the vertical roll biting start position 9, the guide roller 13 and the roll It is best to set the distance between the centers as small as possible.

In FIG. 2, the outer surface of the flange portion B of the rolled steel material 19 is shown held by the vertical guide rollers 17 and 18 supported by the side guide 16, but this is due to the fact that it is not caught in the left and right rolls. This is done in consideration of preventing abnormal biting due to misalignment and friction flaws caused by the friction guide on the inner surface of the flange part B. Even without the vertical guide rollers 17 and 18, it is difficult to improve web center deviation. There is no.

[0023]

[Example] An example in which test rolling of an H-section steel of size H300 x 150 x 6.5/9 was carried out using the mill layout shown in Fig. 7(a) will be explained.

For the test rolling, rolls used in normal production were used for the breakdown mill 1, universal mill 2, edger mill 3, and finishing universal mill 4 shown in FIG. Figure 1, Figure 2
A guide equipped with three pairs of guide rollers 13, 14, and 15 facing the web portion A of the rolled steel material 19 as shown in FIG. 1 was used. In order to compare and evaluate the improvement effect of web center deviation, two pairs of opposing guide rollers 11 and 12 shown in FIG.
Test rolling was conducted under the rolling conditions shown in Table 1 using a conventional guide equipped with a conventional guide and a friction guide used for normal rolling shown in FIG.

[0025]

[Table 1]

The settings of the friction guides are the same as those for normal production rolling, the setting conditions of the 3 pairs of opposed guide rollers and the 2 pairs of opposed guide rollers are the same, and the conditions such as the roll set of each mill shown in FIG. The rolling conditions were set to be the same for all three guides so that comparative evaluation could be made fairly.

The results of the test rolling are shown in Table 2.
This is because vertical bending is particularly likely to occur in the longitudinal direction of the rolled steel material, and the web center deviation is less accurate on the tip side (
The results are shown for the top) and rear end side (bottom).

[0028]

[Table 2]

[0029]

[Outside 1]

Process capability index Cp = (5.0 (width of tolerance) - | outside 2 deviation x 2 |) / 6σ

[0031]

[Outside 2]

The average value of the center deviation S when using each guide, the standard deviation σ representing its dispersion, and the process capability index Cp, which is a guideline for process capability, are shown. Compared to the process capability index Cp of the 3-pair opposed guide roller, which has improved significantly. this is,
The vertical curvature was corrected by three pairs of opposing guide rollers, and the effect of improving the web center deviation was remarkable.

[0033]

[Outer 3]

The definition of the web center deviation S is as explained in FIG.
If it is on the upper side, it is a negative value, and this size H 300
×150 web center deviation tolerance is ±2.5mm (
JIS G 3192).

The present invention is excellent in practicality and makes it easy to obtain highly accurate dimensions with less deviation in the web center of a section steel having a flange, such as an H section steel. Recently, the automation of architectural structure processing has progressed, and in response to the actual situation where there is a growing demand for improved dimensional accuracy, the effect is particularly great since improving the web center bias is a difficult technology.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the mechanism by which an H-beam steel with less web center deviation can be manufactured by the method of the present invention.

FIG. 2 is a diagram showing the configuration of a guide used in the method of the present invention,
Figure (a) is a front view, and Figure (b) is a view taken along the line X--X in Figure (a), with projections of the side guides omitted for simplicity.

FIG. 3 is an explanatory diagram of problems when rolling using a conventional guide configured with two pairs of opposing guide rollers.

FIG. 4 is an explanatory diagram of problems when rolling using a conventional integrated friction guide.

FIG. 5 is an explanatory diagram of the definition of web center bias.

FIG. 6 is a diagram showing a configuration for attaching a guide to a universal mill (FIG. 6(a)) and an edger mill (FIG. 6(b)).

[Figure 7] An example of a mill layout when rolling H-beam steel (Figure 7 (a)), and roll shapes and rolling conditions used in universal mills and edger mills (Figure 7 (b))
FIG.

[Explanation of symbols]

1 Breakdown mill 2 Universal mill 3 Edger mill 4 Finishing universal mill 5 Center of web thickness 6 Center of flange width 7 Pass line 8 Horizontal roll biting start position 9 Vertical roll biting start position 10 Friction guide 11, 12 Guide roller 13-15 Guide roller 16 Side guide 17, 18 Vertical guide roller 19 Rolled steel material

Claims (1)

[Claims] Claim 1: When hot rolling a section steel having a flange using a universal mill, the upper and lower surfaces of the web part of the rolled steel material are held and guided by three or more pairs of opposing guide rollers in the entrance guide of the universal mill. A method for rolling a section steel with little deviation from the center of the web.