JP2520807B2 - Simultaneous rolling method for different steel types and different sizes in multi-strand mill - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-strand mill in which a multi-thread rolling mill row is arranged in the front stage and a multi-thread rolling mill row is arranged in the rear stage for multiple strands. When billets that are rolled to size are rolled at the same time, stable rolling is performed without problems, and as a result, rolling stops due to size changes or a reduction in production efficiency due to the limitation of the strands to be rolled, different steel types and different sizes The present invention relates to a simultaneous rolling method.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 61-186102 discloses a difference in feed rate to a bar rolling line and a wire rolling line in the same rolling line due to a difference between a rolling speed during bar rolling and a rolling speed during wire rolling. Described is a rolling method that eliminates the problem by providing a holding storage in the middle of rolling, mixes the billet for steel bar with the billet for wire rod and heats it in the heating furnace, and then rolls it on the bar rolling line and wire rod rolling line of the same rolling line. Has been done.

However, although there is an idea of charging billets for steel bars and billets for wire rods alternately into a heating furnace, this is the subject of the present application, in which billets of different steel types or different product sizes are rolled for each strand. It is not possible to achieve stable rolling of the billet at the same time without any trouble, and to prevent reduction of production efficiency due to stoppage of rolling due to size change or limitation of strands to be rolled.

[0004]

Conventionally, when rolling is carried out in a multi-strand mill in which a multi-thread rolling mill row is arranged in the front stage and a multi-thread rolling mill row is arranged in the rear stage for multiple strands, whichever strand is used In general, billets that are rolled to the same steel type and the same product size are generally rolled, and charging to the heating furnace has also been performed collectively for each billet that is rolled to the same steel type and the same product size. For this reason, it is strongly desired to establish a technology for simultaneously and stably rolling billets of different steel types for different strands or billets that are rolled into different product sizes.

[0005] In recent years, the delivery schedule to users has become stricter and smaller lots have been developed. However, in the conventional rolling method, the frequency of changing the rolling size increases and the production efficiency is inevitably reduced.

As a regulated cooling facility for wire rods, a regulated cooling facility called Stelmore cooling facility is generally used.
In recent years, a new regulated cooling system has been developed to replace the conventional Stelmore cooling system in response to the needs of customers to omit processes.
It is operating as actual equipment.

However, because the target steel types are limited, the amount of investment is expensive, or due to reasons such as compatibility with other equipment, it is not installed on all strands, but only on some strands. In such a multi-strand mill of wire rods having different adjustment cooling facilities for each strand, when the specific adjustment cooling is performed in the conventional method, the strands that can be rolled are limited and the production efficiency is inevitably reduced. .

On the other hand, in the conventional method, it is difficult to simultaneously roll billets of different steel types for each strand or billets that are rolled into different product sizes from the following points, and there is no example.

First, the rolling characteristics of the billet differ depending on the steel type. For example, a steel type with a small deformation resistance has a smaller width spread and a larger elongation than a steel type with a large deformation resistance. There are many rolling problems caused by.

Further, in the wire rod rolling, it is general that the hole type schedule for rolling the billet to the final product size is divided into several rolling series in which the hole shape and the hole size are different depending on the product size. is there.

Next, there has not been established a method for charging a billet having different attributes (steel type, product size) into a determined strand and for extracting it from the heating furnace in order to reliably extract it.

Therefore, the solution to the above problems is to
It is indispensable to establish a rolling technology for simultaneously and stably rolling billets of different steel types for different strands or billets that are rolled into different product sizes.

The present invention solves the above-described problems, and a billet of different steel types for each strand or a billet that is rolled into different product sizes can be stably and simultaneously rolled without trouble, and a strand that is stopped or rolled by changing the size can be provided. It is intended to provide a simultaneous rolling method for different steel types and different sizes in a multi-strand mill for wire rods, which can prevent a reduction in production efficiency due to limitations.

[0014]

SUMMARY OF THE INVENTION The present invention has the following features.

The first is a multi-strand mill in which a multi-thread rolling mill row is arranged in the front stage and a multi-thread rolling mill row is arranged in the rear stage for multiple strands. In the multi-thread rolling mill row, the same hole shape and the same hole are formed. Simultaneous rolling method for different steel types and different sizes characterized in that each billet of different steel type is rolled under the rolling conditions of the die size, and each product is rolled to a different product size for each strand after the rolling mill train becomes a single-pass rolling. Is.

The second is that each of the strands of the multi-threaded rolling mill train in which billets having different attributes (steel type, product size) are charged into a heating furnace alternately or periodically according to the order of rolling and rolling is performed. It is the above-mentioned different steel type / different size simultaneous rolling method in which extraction from the heating furnace is sequentially performed.

The third is that in a multi-thread rolling mill train, multi-roll rolling of billets of different steel types is carried out under the rolling conditions of the same hole shape and the same hole dimension, and each subsequent one-roll rolling mill train is followed. A looper for tensionless rolling between the rolling mills of the group of intermediate rolling mills to be configured, and a measuring machine for measuring dimensions over the entire length of the rolled material before and after the finishing rolling mill are arranged to roll to different product sizes. This is a simultaneous rolling method for different steel types and different sizes.

Fourth, a twisting guide whose angle can be adjusted for each strand is provided on the outlet side of the rolling mill which requires twisting of the rolling mill row of multi-threading rolling, and rolling from multi-threading rolling to one-thread rolling is performed. The above-described different steel type / different size simultaneous rolling method is one in which a looper having a large loop storage amount is arranged between the rolling mills for rolling.

[0019]

As described below, according to the present invention, in a multi-strand mill for wire rods, when rolling billets of different steel types for different strands or billets that are rolled into different product sizes, stable rolling is possible without any trouble. The present invention acts so as to prevent the production efficiency from being lowered due to the stoppage of rolling due to the size change or the limitation of the strands to be rolled by performing the rolling.

Specific means for simultaneous rolling of different steel types and different sizes will be described below.

First, the hole schedules of the row of rolling mills in the preceding stage for performing the multi-thread rolling are integrated into the hole schedules having a small product size, and rolling is performed under the rolling conditions of the same hole shape and the same hole size.

The reason for the above is to enable the simultaneous rolling of billets to be rolled into different product sizes in a row of rolling mills in the preceding stage where multi-thread rolling is performed. This is because when the product size is small, the rolling reduction rate becomes large after each intermediate rolling mill group in the subsequent stage where one-pass rolling is performed, and exceeds the allowable reduction rate.

Further, a looper for performing tensionless rolling is arranged between each rolling mill of each intermediate rolling mill group of the rolling mill train of the succeeding rolling mill train to be one-roll rolling, and measurement is performed before and after the finish rolling mill following the rolling mill train. Arrange the machine and roll into different product sizes for each strand.

The reason for the above is that the hole schedule of the former rolling mill train, which is a multi-thread rolling, is integrated into the hole schedule of a small product size, so that for other product sizes, the target rolling mill train is the target product in the succeeding rolling mill train. Since it became more difficult to roll to size, the tension steel rolling by arranging the looper was performed to stabilize the dimension of the pressure steel after the intermediate rolling mill, and the dimension of the pressure steel after the intermediate rolling mill and Since it is known that there is a strong correlation between the dimensions of the pressed steel, it is possible to perform rolling adjustment based on the measurement data over the entire length of the rolled material with a measuring machine and accurately roll to the product size. To do.

Next, a twisting guide whose angle can be adjusted for each strand is provided on the exit side of the rolling mill that requires twisting of the rolling mill row for multi-threading rolling. A looper with a large loop storage amount is placed in between to perform rolling.

The above-mentioned reason is to absorb the difference in rolling characteristics depending on the steel type and to stably perform the rolling of different steel types in the multi-row rolling mill train. Here, the difference in rolling characteristics depending on the steel type is as follows. Since a steel type with a low C content has a small deformation resistance, the twist angle can be small, the width is small, and the drawing is large. In the case of steels with a high C content, since the deformation resistance is large, the twist angle is large, the width is wide, and the stretching is small.

Therefore, in order to simultaneously and stably roll different steel types in each multi-roll rolling mill, the twist angle can be adjusted for each strand in the twist guide, and rolling of the multi-roll rolling mill train is possible. It is necessary to absorb tension fluctuations that occur between machines.

Therefore, as the twisting guide, a compact guide having a guide width within the strand interval and capable of adjusting the twisting angle for each strand is adopted, and is provided between rolling mills moving from multi-thread rolling to single-thread rolling. A looper with a large amount of loop storage that absorbs tension fluctuations is placed.

As a method of charging and extracting the billet into the heating furnace, billets having different attributes (steel type, product size) are charged into the heating furnace alternately or periodically according to the rolling order, and rolling is performed. The strands are sequentially extracted from the heating furnace.

Here, as the combination of billets having different attributes (steel type, product size), one-to-one, 1 or 1 depending on the combination of product sizes to be rolled or the installation condition of the adjusting cooling equipment.
It is possible to employ various combinations, such as pair 2, pair 1, pair 4, pair 6, pair 1, pair 1, and pair 1.

The combination of 1: 2, 1: 4, and 1: 6 is a method of rolling a billet having different attributes (steel type, product size) from other strands by only one strand in the three-strand rolling. When charging into and out of the heating furnace at a ratio of 1 to 2 or at a ratio of 1 to 4 or at a ratio of 1 to 6 alternately or periodically This is the combination used.

Next, a detailed description will be given with reference to the drawings.

FIG. 1 is a diagram showing a layout of a multi-strand mill of a wire to which the present invention is applied.

In FIG. 1, No. No. 1 strand and No. Two
Stelmore cooling equipment 6, No. 6 as an adjustment cooling equipment for the strand. A new adjusted cooling equipment 7 is provided on 3 strands. The coarse and one intermediate rolling mill train 2 is multi-rolling rolling, and the two intermediate rolling mill trains 3 and after are single-rolling rolling. 1 is a heating furnace, 4 is a finish rolling mill, 5 is a winder, and 8 is a focusing facility.

FIG. 8 shows an example of a conventional hole type schedule. Only the hole type of the rough roll rolling mill is shared, and the hole type of one intermediate rolling mill row 2 is divided into two types, and the product size that can be simultaneously rolled is limited according to the hole type schedule.

FIG. 2 shows an example of the hole schedule according to the present invention. The rough and multi-thread rolling and the hole type up to one intermediate rolling mill row 2 are shared, and simultaneous rolling is possible over all product sizes on the hole type schedule.

FIG. 3 shows a row 3 of two intermediate rolling mills for single-pass rolling.
The outline of the side looper 10 arranged as the looper for performing the tensionless rolling arranged on the rolling mill 9 of FIG. Reference numeral 11 is a material to be rolled.

4 and 10 show the side looper 10
The effect of non-tension rolling is shown. FIG. 10 shows the dimensions of the material 11 to be rolled in the two intermediate rolling mills when the side looper 10 is not arranged between the rolling mills 9 and the rolling mills 9 of the two intermediate rolling mill trains, which are single-pass rolling. Is a graph showing the relationship with the top-bottom dimension; x: left-right dimension).

FIG. 11 is a cross-sectional view when the material 11 to be rolled is rolled by the upper roll 14 and the lower roll 15, and is an explanatory view showing measurement positions of the vertical dimension and the lateral dimension of the rolled material 11.

FIG. 4 is a kraft showing the same relationship as in FIG. 10 when the side looper 10 is arranged.

As shown in FIG. 10, before and after the side looper is arranged, the lateral dimension is about 3% smaller than the vertical dimension due to the effect of the tension between the stands, whereas {(17.8 mm
−17.3 mm) ÷ 17.3 mm × 100 = 2.9
%}, After the side looper is arranged, the horizontal dimension is almost the same as the vertical dimension as shown in FIG. 4, and the dimension of the material to be rolled on the side where the two intermediate rolling mills are lined up is improved.

FIGS. 5A, 5B and 5C show rolling of a rolling mill train for performing multi-thread rolling during simultaneous rolling of the low C material SWRM10 and the high C material SWRH72A according to the present invention. The difference in the twist angle of the twist guide 12 arranged on the machine exit side is shown. Reference numeral 11 is a material to be rolled. In the SWRM 10 shown in FIGS. 5A and 5B, the twist angle of the twist guide is 22 °, and in the SWRH 72A shown in FIG. 5C, the twist angle is 28.
It has become °.

Here, when the twisting angles are the same, the guide to the next rolling mill becomes poor, which causes the trouble of the entrance guide of the next rolling mill or the abnormal quality due to the poor guide to the rolling roll caliber. Becomes Therefore,
It can be seen that it is necessary to adjust the twist angle for each strand, and it is essential to adopt the compact guide of the present invention in which the guide width is within the strand interval and the twist angle can be adjusted for each strand.

In FIG. 6, the material to be rolled 11 is subjected to multi-rolling and is subjected to single-rolling from a row of one intermediate rolling mill 2 and 2
Looper 1 placed between stands moving to intermediate rolling mill train 3
3 is shown. Since the loop storage amount is larger than that of the conventional side looper, it absorbs the tension fluctuation in the multi-thread rolling mill. Here, when a looper with a small loop storage amount is adopted, it is impossible to absorb the tension fluctuation in the multi-thread rolling mill, and the loop fluctuation becomes large, which causes a trouble.

FIG. 9 shows an example of charging into the conventional heating furnace and extraction from the conventional heating furnace. Here, the lot X is a set of billets of the steermore cooling target material, and the lot Y is a set of billets of the newly adjusted cooling target material. When rolling the billet of the lot X, the No. No. in which the Stelmore cooling equipment is installed is used. No. 1 strand and No. Since it will be extracted only in 2 strands, the No. The three strands were stopped for rolling due to waiting for extraction.

The new adjustment cooling equipment is No. Since it is arranged only on three strands, when rolling lot Y, No. No. 1 strand and No. Two strands were stopped for rolling due to waiting for extraction.

FIG. 7 shows an example of charging into the heating furnace and extraction from the heating furnace according to the present invention. By periodically charging the billet X of the Stelmore cooling target material and the billet Y of the new adjusted cooling facility into the heating furnace at a ratio of 1: 2, the billet X is No. 1 in which the Stelmore cooling facility is arranged. No. 1 strand and No. To the 2nd strand, the billet Y is No. 2 where the new adjustment cooling equipment is installed. It becomes possible to continuously extract to three strands, and it is possible to perform extraction without causing rolling stop on any strand.

In this example, the billet to be subjected to the new adjusted cooling treatment and the billet to be subjected to the Stelmore cooling treatment are rolled in different strands at the same timing, but the billet rolled into different product sizes in each strand. Even when rolling, by combining billets that are rolled into different product sizes in an appropriate ratio, by alternately or periodically charging and extracting from the heating furnace, which strand is Also, it becomes possible to carry out rolling without causing rolling stop.

[0049]

EXAMPLES First, equipment conditions will be described.

Walking beam heating furnace, N in front
o. No. 1 strand rolling, No. 2 strand rolling and no. A multi-strand mill in which a three-thread rolling mill train consisting of three-strand rolling and a one-thread rolling mill train of one-strand rolling for three strands were arranged in the subsequent stage was prepared. During the three-pass rolling, the rolling conditions were the same hole shape and the same hole size. The row of three rolling mills is a rolling mill group of 12 rolling mills (No. 1).
-No. 12 stands), and the single rolling mill row was composed of 14 rolling mill groups (No. 13 to No. 26 stands).

A row of two intermediate rolling mills (No. 13 to No. 16) constituting each row of one rolling mill following the row of three rolling mills.
A side looper for performing tensionless rolling between the rolling mills of the stands) is provided with a finishing rolling mill (No.
17-No. 26 stand) and a measuring machine for measuring the dimension of the entire length of the rolled material is arranged before and after the stand. On the outlet side of the rolling mill that requires twisting of the rolling mill train (coarse and one intermediate rolling mill train) for three-pass rolling, a twist guide with adjustable angle for each strand is provided from three-roll rolling to one-roll rolling. A looper with a large loop storage amount was placed between the rolling mills to be transferred.

No. No. 1 strand and No. A finish rolling mill, a winder, and a Stelmore cooling facility were arranged after each two intermediate rolling mill rows (No. 13 to No. 16 stand) of two strands. No. A finish rolling mill, a winder, and a new adjusted cooling facility were arranged after the row of two intermediate rolling mills (No. 13 to No. 16 stand) of 3 strands.

Next, the operating conditions will be described.

No. No. 1 strand and No. Billet of low carbon steel rolled by 2 strands (cross-sectional dimension: 1
22 mm × 122 mm; length: 18,000 mm; unit weight: about 2 t) 2 pieces; Billet of special welding steel that is rolled in the 3-strand rolling section (section size: 122 m
mx122mm; length: 18,000mm; unit weight: about 2
t) One is alternately (periodically) charged into a walking beam type heating furnace, and extracted into each predetermined strand of a rolling train of three-pass rolling to have the same hole shape and the same hole size. Rolled.

Thereafter, the finishing rolling speed is set to 5 in the single-pass rolling train.
Finishing rolling is performed at 1 m / s, winding, and cooling to obtain a low carbon steel wire rod product (diameter 6.5 mm; length about 8,
000 m) per hour and 60 t per hour, and a special welding steel wire rod product (diameter 5.5 mm; length about 11,000 m) was obtained per hour 30 t.

As a result of carrying out the present invention as described above,
1 when rolling a billet that undergoes the new adjusted cooling process
Although it was a full thread rolling, the present invention enables three thread rolling, and the production efficiency is improved to three times that of the conventional method.

[0057]

According to the present invention, in a multi-strand mill for wire rods, when rolling billets of different steel types or billets rolled into different product sizes for each strand, stable rolling is performed without trouble, Rolling can be performed while preventing the production efficiency from being reduced due to the stop of rolling due to size change or the limitation of strands, and the production capacity can be improved. In addition, it will be possible to meet stricter delivery deadlines to users and to make smaller lots.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a layout of a multi-strand mill to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of a hole schedule according to the present invention.

FIG. 3 is a perspective view showing an example of an outline of a looper for performing tensionless rolling, which is arranged between rolling mills of two intermediate rolling mill trains to be one-pass rolling.

FIG. 4 is a graph showing a dimensional change of a material to be rolled on the feed side of a two intermediate rolling mill, showing the effect of tensionless rolling by a looper.

FIG. 5 shows a twisting situation in a twisting guide during simultaneous rolling of a low C material and a high C material according to the present invention. 5 (a), (b),
(C) shows the No. Nos. Arranged on the rolling mill exit side of the multi-thread rolling mill train. For 1 strand, No. For 2 strands,
No. It is a partial longitudinal cross-sectional perspective view which shows an example of the outline of the twist guide for 3 strands.

FIG. 6 is a schematic perspective view showing an example of a looper arranged between rolling mills for shifting from multi-thread rolling to single-thread rolling according to the present invention.

FIG. 7 is an explanatory view showing an example of a method of charging into a heating furnace and extracting from the heating furnace in the present invention.

FIG. 8 is an explanatory diagram showing an example of a conventional hole schedule.

FIG. 9 is an explanatory view showing an example of a method for charging into a conventional heating furnace and extracting from the conventional heating furnace.

FIG. 10 is a graph showing a change in the dimension of a material to be rolled on the exit side of the two intermediate rolling mill trains when a looper is not arranged between the rolling mills of the two intermediate rolling mill trains that are single-pass rolling.

FIG. 11 is a cross-sectional view when the material to be rolled 11 is rolled by the upper roll 14 and the lower roll 15, and is an explanatory diagram showing measurement positions of the vertical dimension and the lateral dimension of the rolled material 11.

[Explanation of symbols]

 1 heating furnace 2 rough and 1 intermediate rolling mill train 3 2 intermediate rolling mill train 4 finish rolling mill 5 winder 6 Stelmore cooling facility 7 new adjusted cooling facility 8 focusing facility 9 2 intermediate rolling mill 10 side looper 11 rolled material 12 Twist guide 13 Looper 14 Upper roll 15 Lower roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Senda 23-15 Suzuko-cho, Kamaishi-shi, Iwate Nippon Steel Corporation Kamaishi Steel Co., Ltd. (56) Reference JP-A-56-17104 (JP, A) JP 59-202102 (JP, A) JP 60-13540 (JP, Y2)

Claims (4)

(57) [Claims] 1. In a multi-strand mill in which a multi-thread rolling mill row is arranged in a front stage and a single-thread rolling mill row is arranged in a rear stage for multiple strands, rolling conditions of the same hole type and the same dimensions in the multi-thread rolling mill row. A different steel type / different size simultaneous rolling method is characterized in that each billet of a different steel type is rolled with, and rolling is performed to a product size different for each strand after the rolling mill train that becomes a single-pass rolling. 2. Each strand of the multi-threaded rolling mill train in which billets having different attributes (steel type, product size) are charged into a heating furnace alternately or periodically according to the rolling order and rolling is performed. The simultaneous rolling method for different steel types and different sizes according to claim 1, wherein extraction from the heating furnace is performed sequentially. 3. In the multi-thread rolling mill train, billet of different steel type is multi-thread rolling under the rolling conditions of the same hole shape and the same hole dimension, and each one-roll rolling mill train is formed subsequent to it. A looper for performing tensionless rolling is provided between the rolling mills of the intermediate rolling mill group, and a measuring machine for measuring dimensions over the entire length of the rolled material is arranged before and after the finishing rolling mill to perform rolling to different product sizes. Alternatively, the different steel type / different size simultaneous rolling method described in 2. 4. A rolling machine, in which an angle can be adjusted for each strand, is provided on the exit side of the rolling mill that requires twisting of a rolling mill train for multi-threading rolling, and which shifts from multi-threading rolling to single thread rolling. The different steel type / different size simultaneous rolling method according to any one of claims 1 to 3, wherein a looper having a large amount of loop storage is arranged between them for rolling.