JPS62151209A - Rolling method for steel sheet - Google Patents

Abstract

PURPOSE:To obtain a thin steel sheet having the material characteristics and surface characteristics approximate to the characteristics of a cold rolled steel sheet while preventing the increase of rolling torque by rolling the steel sheet with a hot reversing mill then with a warm reversing mill. CONSTITUTION:The steel sheet 6 un-coiled from a coiling and un-coiling machine 4 is rolled by the hot reversing mill 1 and is coiled by a coiling and un-coiling machine 5 while the warm reversing mill 2 is held open and a cooler 3 is held closed. The coiled steel sheet 6 is un-coiled from the machine 5 and is rolled by the hot reversing mill 1, then the rolled sheet is coiled by the machine 4. The steel sheet is then un-coiled from the machine 4, is rolled by the hot reversing mill 1, is cooled by the cooler 3 and is coiled by the machine 5. The steel sheet 6 un-coiled from the machine 5 in the open state of the mill 1 is cooled down to the prescribed warm rolling temp. by the cooler 3 and is then rolled by the mill 2 and is coiled. The steel sheet 6 un-coiled from the machine 4 is rolled by the mill 2 and is taken up on a take-up machine 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hot reverse mill and a method for manufacturing steel sheets using a warm reverse mill.

Prior Art Currently, steel plates are divided into hot-rolled steel plates and cold-rolled steel plates. Hot-rolled steel sheets are mainly used as cold-rolled fA temporary materials, ÷1 materials, vibration material, and structural steel sheets, and cold-rolled steel sheets require excellent workability and good surface properties. Used in automatic Ichikawa steel plates, etc. Hot-rolled steel sheets are rolled at a temperature higher than the recrystallization temperature of the rolled material, and cold-rolled steel sheets are usually rolled at around room temperature. It has material properties and surface properties comparable to those of cold-rolled steel sheets, but it is also cheaper than cold-rolled steel sheets, making it a steel sheet that is expected to be widely used in the future. Technical research on 4-way rolling is already progressing, and for example, in rimmed steel, f! 4 temporary with a reduction rate of 60% or more at 450 ° C or less
It has been technically found that by performing inter-rolling, a steel plate with good drawability equivalent to cold-rolled Joetsu steel plate can be obtained.

As a process for performing the above-mentioned warm rolling, there is a method in which a warm rolling mill is connected subsequent to a hot rolling mill and rolling is performed for 6 hours.

Figure 3 shows a warm rolling mill located behind the hot rolling mill N2
In this diagram, steel fkte+ is first subjected to hot IE f
It is hot rolled in a mill (8), then cooled down to a predetermined rolling thickness in a cooling device (3), and then transferred to a warm 1F rolling mill (
9) for 4 hours and then wound up using a winder (η).

However, in the above-mentioned method in which a hot rolling mill is disposed following a hot rolling mill to perform warm rolling, degrees (8
50°C) or higher, the rolling speed must be as high as that of current pot strip mills, and in order to lower this to the temperature required for warm rolling, cooling is required between the hot rolling mills and the warm rolling mills. There are problems in that the length of the equipment is long, about 400 m, and the 4-way rolling is high-speed and low-temperature rolling, so the rolling torque is large and an excessively large mill is required.

The present invention solves the above-mentioned problem and produces thin steel sheets at low cost that have material properties and surface properties similar to those of cold-rolled steel sheets. The purpose is to provide a method for JW.

Structure of the Invention The present invention has been made for the above-mentioned purpose, and its gist is to provide a hot reverse mill, a warm reverse mill, and a cooling device in series, or a hot reverse mill and a warm reverse mill. are installed in series, and a winding/unwinding machine is installed on the entry and exit sides of the equipment connected in series, and hot rolling is carried out to a predetermined thickness using a hot reverse mill. The method of rolling a steel plate is characterized in that after cooling to a temperature, the steel plate is warm rolled to a predetermined thickness using a warm reverse mill.

Here, hot rolling refers to rolling at a temperature higher than the crystallization temperature of the rolled material, and L-rolling refers to rolling at a temperature higher than the recrystallization temperature (700°C to 700°C).
100°C).

FIG. 1 is an explanatory diagram showing the configuration of an example of an apparatus for carrying out the present invention. In the figure, two hot reverse mills (1) and one warm reverse mill (■) are arranged in series, followed by a cooling 'A I+7 (31).The cooling device (3) and A winding/unwinding machine (4), (((
) will be placed. A winding machine (7) for winding up the rolled steel plate (6) is installed downstream of the winding/unwinding machine (5).
) will be installed.

The number of reverse mills to be installed is one to two for both cold rolling and warm rolling, and the appropriate number of reverse mills to be installed is determined in consideration of material thickness, product thickness, production scale, etc.

The cooling device (3) is provided with equipment for cooling the material to be rolled, such as a spray set watering equipment, as required.

Next, the method of the present invention will be explained based on the drawings using the apparatus having the above configuration. FIG. 2 is an explanatory diagram showing an example of a process in which hot rolling and warm rolling are performed using the SA apparatus having the configuration shown in FIG. 1.

In the figure, the warm reverse mill ■ is open and the cooling bag u!
2 (3) is in the closed state, and the steel plate (6) unwound from the winding/unwinding machine (4) is rolled in the hot reverse mill (1) and wound onto the winding-unwinding a (5). taken (a). The rolled steel plate (6) is unwound from the winding/unwinding machine 6), rolled by the hot reverse mill (1), and then rolled up by the winding/unwinding machine (4) ( ). The wound W4 temporary (6) is rewound from the winding/unwinding machine (4), rolled to a predetermined thickness in a hot reverse mill (1), and then cooled in a cooling device (3). , and is wound up by the take-up and unwinding machine (5) (c). The hot reverse mill (violet) is open,
The steel plate (6) unwound from the winding/unwinding machine (5) is cooled to a predetermined warm rolling temperature in a cooling device (3), then rolled in a warm reverse mill (2), and rolled. Take-up and rewind machine (
4) It is wound up (=). Next, the winding/rewinding machine (
The steel plate (6) rewound from 4) is heated in a warm reverse mill■
The rolled product is rolled to a predetermined thickness using a 1r12 winding machine (forced (e)). - In the rolling process described above, the number of baths in the hot reverse mill (1) and warm reverse mill (2) is 6 and 6, respectively. 2 times, but the number of buses is
I! It can be determined by considering l-1 product thickness, etc.

When a cooling device is not provided, after hot rolling is performed using a hot reverse mill, cooling is performed by air cooling to a predetermined temperature, and then rolling is performed for 4 hours using a warm reverse mill.

] - In foot hot rolling and warm rolling, hot rolling is rolled at a temperature higher than the recrystallization temperature, so it is high speed rolling6, but 4-way rolling does not need to be high speed, and rolling torque is not increased. Rolled at low speed.

The above is a case of manufacturing a 4-way rolled steel plate, but the iA
A hot rolled steel plate can be produced using only the hot reverse mill (1) at the same time.

Example The following is a description based on examples.

A thin slab having a thickness of 30 mm was rolled by the method of the present invention to a thickness of 1.2 mm using an apparatus having the configuration shown in FIG. Table 1 shows the rolling specifications. The number of baths was 6 times for hot rolling and 2 times for warm rolling, which is the same as in the case shown in FIG. Cooling was performed by spraying water to a predetermined warm rolling temperature.

The results are shown in Table 2. In the same table, the conventional method is a rolling method for manufacturing ordinary cold rolled steel sheets. From the same table, the rolled steel sheet obtained by the method of the present invention has a Lankford value (r value) of 1.8, and is a normal cold rolled steel sheet with an r value of 1.5 to 2.2. It can be seen that the surface quality is also very good.

(Here are blanks) Table 1 Table 2 Effects of the Invention As described above, by the method of the present invention, which involves rolling with a hot reverse mill and then rolling with a warm reverse mill, the rolling speed of warm rolling can be increased by heating. It can be controlled independently of the rolling speed during inter-rolling, and low-speed rolling is possible during warm rolling. As a result, it is possible to prevent the rolling torque from increasing despite warm rolling, and the rolling mill can be used as a compact 1. The length of the cooling device that lowers the temperature of the material to be rolled to the warm rolling temperature can also be significantly shortened.

In addition, the obtained warm rolled steel sheet has a high r value and 1m drawability comparable to that of cold rolled steel sheet, and since the hot rolling mill and the warm rolling mill are separate rolling mills, Because it is possible to select a J-ru material that is suitable for both rolling and warm rolling, it has excellent surface properties that are close to those of cold-rolled steel sheets.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an example of an apparatus for carrying out the present invention, FIG. 2 is an explanatory diagram showing an example of the steps of the method of the present invention, and FIG. It is an explanatory view showing the composition of an example of a device. 1... Hot reverse mill 2... Warm reverse mill 3... Cooling device 4... Winding ψ unwinding machine 5...
・Take-up e-unwinder 6... Steel plate 7... Winder
8...Hot rolling mill 9...l! Inter-rolling mill applicant Sumitomo Metal Industries Co., Ltd., - to agent patent attorney ``2 Yoshikawa! ■-21□ :゛::E: 1. , :,' l-27 and -1 Figure 1 1 heat 1 season lζ-su SIV 20th

Claims (1)

[Claims] A hot reverse mill, a warm reverse mill, and a cooling device are installed in series, or a hot reverse mill and a warm reverse mill are installed in series, and winding and unwinding are performed on the input and output sides of the connected device. 1. A method of rolling a steel plate, comprising: disposing a hot reverse mill, performing hot rolling with the hot reverse mill, cooling to a predetermined temperature, and then performing warm rolling.