JP2003285102A - Method for transferring identification mark on h-shape steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for transferring an identification mark on an H-shape steel product which can transfer the mark clearer than ever on the product without giving bad effect on its quality and shape. <P>SOLUTION: To manufacture an H-shape steel, a steel slab is successively passed through a break-down mill, a rough rolling mill and a finish rolling mill. In order to roll an H-shape steel product with its identification mark, which shows its manufacturer and so on, on its web or flange, the rough rolling mill employs rolls with stamped identification mark to transfer the mark on the steel slab, while the finish rolling mill employs rolls with a concavity wider than the width of the mark so that the finish rolling does not apply reduction on the transferred mark. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring a roll mark to an H-section steel, and more specifically, as a mark for indicating a source, which is pre-engraved on a roll in order to clarify the source of the H-section steel. The present invention relates to a technique for transferring a so-called "roll mark (also referred to as a raised letter)" from a roll during rolling of H-section steel.

[0002]

2. Description of the Related Art ASTM (American Soci)
ety for Testing and Mater
In the standards, etc., in order to clarify the origin of shaped steel products, letters, numbers, figures, etc. that represent the manufacturer name or company mark, etc. shall be displayed at regular intervals in the longitudinal direction of the product. Is obligatory. Usually these figures are
It is called a roll mark because it is engraved on the surface of the roll in advance and transferred from the roll to the material to be rolled when rolling. Since this roll mark is generally displayed on a product in an embossed state, it is engraved in a recessed state on the roll.

In the case of H-section steel, which is the most representative section steel,
In the final mill of the rolling process (finishing universal mill, hereinafter simply referred to as finishing mill), transfer is performed on the web or flange of the H-section steel. At that time, conventionally, measures have been taken to sufficiently increase the reduction amount of the web or flange in the finishing mill or to secure a rolling temperature suitable for transfer so that the transferred roll mark becomes clear. Further, in order to engrave the roll mark on the roll in advance, it is the actual situation that the shape of the roll mark is simply ground on the roll surface.

[0004]

However, in the conventional method of transferring the roll mark to the product by such a finishing mill, if the reduction amount of the web or the flange and the rolling temperature cannot be secured as desired, the roll mark becomes unclear. Tended to become. On the other hand, if rolling is performed with priority given to clarifying the roll mark, "material control" that sets the mechanical properties of the product to desired values according to rolling conditions, appropriate setting of water cooling conditions, and finishing mill There is also a problem that it is difficult to manufacture a high-quality H-section steel because the so-called "shape control" for increasing the shape accuracy by controlling the rolling load and the rolling temperature is significantly restricted.

In view of such circumstances, it is an object of the present invention to provide a method of transferring a roll mark to an H-section steel capable of transferring a clear roll mark to a product without affecting the material or shape.

[0006]

Means for Solving the Problems The inventor has conducted extensive studies in order to achieve the above object, and realized the results in the present invention.

That is, according to the present invention, the steel slab is sequentially passed through a breakdown mill, a rough rolling mill and a finishing mill for producing an H-shaped steel, and the web or flange of the product is provided with a roll mark as an origin. When rolling into H-section steel, the roll mark is transferred to the steel slab by using the roll marked with the rough rolling mill, and the transferred roll mark is not pressed down in the finishing mill. As described above, the roll mark transfer method to the H-section steel is characterized in that a roll having a recess whose width is wider than the width of the roll mark is used. In this case, the recess side surface of the roll mark stamped on the roll used in the rough rolling mill and having the shape of letters, numbers and / or figures is enlarged and inclined toward the opened steel slab side in a cross-sectional view. Along with
The angle (θ) of the side surface of the recess is preferably 60 ° or less.

In the present invention, a roll in which roll marks are engraved is used in the rough rolling mill, not in the finishing mill, and the roll marks are transferred so as not to be pressed by the finishing mill. Not only can the temperature of the steel slab be raised and the amount of reduction can be sufficiently secured, but the feasible range of the "material control" and water cooling conditions can be greatly expanded. In addition, the degree of freedom of "shape control" is increased by changing the rolling load and rolling temperature in the finishing mill. Furthermore, when engraving the roll mark on the roll used in the present invention by grinding, the concave side surface of the roll mark having the shape of letters, numbers and / or figures is enlarged to the opened steel slab side in a cross-sectional view. , And the angle (θ) of the side surface of the concave portion satisfies 60 ° or less.
It becomes possible to solve the problem of making the roll mark unclear when the steel slab comes out of the roll, and also to prevent the roll mark in the middle pass of the rough rolling mill that normally performs multiple reciprocal rolling from becoming a surface flaw. It can be erased to clear only the roll mark of the final pass.

As described above, it is certain that when the present invention is carried out, a clear roll mark can be transferred to a product without affecting the quality and shape of the H steel.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 3 (a) and 3 (b), the H-section steel manufacturing process, which is the subject of the present invention, uses a breakdown mill 2 equipped with a caliber (hole type) roll 1 to cast steel. The piece 3 is roughly rolled to form a rough H-shaped steel cast piece 3. Then, subsequently, a single pass or a plurality of reciprocating (reverse) rollings are sequentially performed by a rough rolling mill 6 and a finishing mill 7 each of which is a universal mill in which a pair of vertical rolls 4 and horizontal rolls 5 are combined, The slab 3 is formed into an H shape having a product shape and size. Conventionally, such H
In the manufacturing process of shaped steel, a vertical mill 4 and a horizontal roll 5 in which a roll mark (for example, an English letter "K") is engraved as a recess on a finishing mill 7 at the final stage, a web 8 of an H-shaped steel slab 3 or The roll mark was transferred to a portion called flange 9.

First, the inventor examined the transfer of clear roll marks. Then, not the finishing mill 7 but the rough rolling mill 6 that performs the preceding rolling is used to transfer by using the horizontal roll 4 or the vertical roll 5 with the roll mark. The reason is that if the roll mark is transferred by the rough rolling mill 6, the rolling temperature is not only easily secured as compared with the case where it is transferred by the finishing mill 7, but also the formability is secured, It is possible to increase the height of the protrusion of the transferred roll mark. Further, it is possible to obtain the reduction amount by comparing the withstand load with the finishing mill 7.

Specifically, the web 8 or the flange 9 of the steel slab 3 which has already been roughened by the breakdown mill 2 is used by using a roll in which roll marks are engraved on the rough rolling mill 6 in the pre-rolling stage. The roll mark is transferred to the portion corresponding to. However, in this case, in order for the roll mark transferred by the rough rolling mill 6 to remain in the final product, it is passed through the finishing mill 7 after that, so it is necessary to devise the shape of the rolls 4 and 5 used in the finishing mill 7. is there. Therefore, the inventor has applied the roll of the finishing mill 7 to the rolls shown in FIGS.
The dent 1 whose width is wider than that of the roll mark as shown in 1
The present invention using the roll provided with 1 has been completed. In this way, the roll marks transferred by the rough rolling mill are not rolled down, and the lift is larger than in the past, so even if the rolling in the finishing mill 7 is performed under quality-oriented conditions, the roll mark position A sufficient reduction amount can be secured, and the roll mark remains in a clear state.

In the present invention, the width (w) of the recess 11 needs to be wider than the width of the roll mark, because a part of the roll mark provided by the rough rolling mill may be crushed. Further, the depth (d) of the recess 11 is related to the required height of the protrusion, and is not particularly limited.

In order to further improve the present invention, the inventor also studied a method of marking roll marks on the rolls 4 and 5 by bite grinding. as a result,
It has been found that it is sufficient to enlarge and incline the recess side surface of the roll mark to be engraved toward the opened steel slab side in a cross-sectional view, and to make the angle (θ) of the recess side surface satisfy 60 ° or less. This has also been added to the present invention.

The reason for satisfying the angle of the concave side surface 14 of 60 ° or less is that the rough rolling is usually performed in a plurality of passes, so that the roll mark of preforming is erased for each pass and a new roll mark is left. This is to prevent the roll mark in the middle of being erased from becoming a harmful surface flaw. Although the actual roll mark 13 is a character, a number, a figure, or the like, in order to simplify the explanation, when the example of the rectangular mark is shown, the above-mentioned θ is changed as shown in FIG.

[0017]

Example 1 In producing a large number of H-section steels in the steps shown in FIGS. 3A and 3B, the present invention in which roll marks are transferred by a rough rolling mill was carried out. As for the size of the H-section steel, the web height was 326.7 mm and the flange width was 319.7 mm, and transfer was performed on any of these. The roll mark is the letter "I".
And the transfer was performed every 2.4 m in the longitudinal direction of the H-section steel. Further, in order to confirm the effect of the present invention, transfer was performed by a conventional method. At that time, in the practice of the present invention, the steel slab that has passed through the breakdown mill, the roll mark is transferred to the steel slab using a roll with a roll mark engraved in a rough rolling mill, and then transferred in a finishing mill. Normal rolling was performed under the conditions of "material control" and "shape control" using a roll having a shape that did not roll down the formed roll mark. The side angle (θ) of the concave portion of the stamp on the rough rolling mill is 60.
It was °.

The results are evaluated by the average height of the transferred roll marks, and shown in Table 1 together with the rolling conditions. From Table 1, it is clear that according to the present invention, the roll mark becomes higher than the conventional one, and the sharpening can be achieved.

[0019]

[Table 1]

Example 2 Under the same conditions as in Example 1A, a rough rolling roll was engraved and a roll mark was transferred. that time,
The angle (θ) of the marking was variously changed. As a result, the roll height could be secured as in Example 1A, but a difference was found in the defect occurrence rate depending on the angle (θ). The rate of occurrence of flaws was evaluated by the ratio of the number of products remaining as flaws on the web surface or flange surface after commercialization. From Table 2, it is clear that the flaw occurrence rate is remarkably improved when θ is 60 ° or less.

[0021]

[Table 2]

As described above, according to the present invention in which transfer is performed by the rough rolling mill, "material control" in the finishing mill and a large degree of relaxation of water cooling conditions can be realized, and the roll mark can be obtained without degrading the quality of the H-section steel. Can be transcribed. As a result, it has become possible to manufacture an H-section steel having a clear roll mark than before. Furthermore, there are merits such as an improvement in the direct shipping rate due to the improvement in the accuracy of shape control.

[0023]

As described above, according to the present invention, it is possible to transfer a sharper roll mark to the H-section steel of the product than before, without affecting the quality and shape.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a shape of a roll to be subsequently used in a finishing mill in the present invention in which a roll mark is transferred by a rough rolling mill, where (a) is a horizontal roll and (b) is a vertical roll. .

FIG. 2 is a side view showing an angle (θ) of a concave side surface of a roll mark stamped on a roll.

FIG. 3 is a diagram illustrating a basic manufacturing process of H-section steel, (a) showing a flow of rolling steps, and (b) showing roll arrangement of a rolling mill used in each step. .

[Explanation of symbols]

1 Roll with caliber (hole type) 2 Breakdown mill 3 Steel slab 4 vertical rolls 5 horizontal rolls 6 rough rolling mill 7 finishing mill 8 web 9 flange 11 dent 12 roll rotation direction 13 roll mark

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Inamura             1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama             Shi) Kawasaki Steel Co., Ltd. Mizushima Steel Works F-term (reference) 4E002 AC03 BA04 BB20 CB10                 4E016 AA07 BA08 DA11 DA19 DA20

Claims (2)

[Claims] 1. A H-section steel having roll marks indicating the origin on a web or flange of a product, which is obtained by sequentially passing the steel slab through a breakdown mill, a rough rolling mill and a finishing mill for producing the H-section steel. At the time of rolling, in the rough rolling mill, the roll mark is transferred to the steel slab using a roll engraved with the roll mark, and in the finishing mill, so as not to roll down the transferred roll mark, the width The method for transferring a roll mark to an H-section steel is characterized in that a roll provided with a recess wider than the width of the roll mark is used. 2. The recess side surface of the roll mark stamped on the roll used in the rough rolling mill and having the shape of letters, numbers and / or figures is enlarged and inclined toward the opened steel slab side in a cross sectional view. In addition, the angle (θ) of the side surface of the recess is 6
The method for transferring a roll mark to an H-section steel according to claim 1, wherein it is 0 ° or less.