JPS61206506A - Installation for manufacturing hot-rolled steel sheet - Google Patents

Abstract

PURPOSE:To reduce the initial cost of the titled installation by arranging an electric furnace for producing a molten steel, a twin-roll type or an endless-track type continuous sheet-casting machine and a few hot tandem mill on an on-line. CONSTITUTION:A high-quality molten steel 2 produced by an electric furnace 1 by using as raw materials, scraps and reduced iron, is transferred to a tundish 4 from a ladle 3 and is poured into a continuous casting machine 5. A cast strip 7 is kept at an uniform temperature by an edge heater 6, and is finished into a prescribed thickness by passing it through a finishing mill 8. Thereafter, the strip 7 is taken up by a winder 11 through a cooling device 9 and a shear 10. In this way, a hot-rolled steel-sheet manufacturing installation low in initial cost and running cost, is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to hot rolled steel plate manufacturing equipment.

[Prior Art] The most common method for manufacturing hot-rolled steel sheets, especially thin steel sheets, and still practiced today, is to cast molten steel manufactured by the blast furnace-converter method into a continuous slab casting machine. The cast thick slab is rolled 10 times or more on a separate hot rolling line (usually 114 rough rolling stands,
Finishing rolling machine (7 stands)) The product is thinned and wound using a winding machine to form a hot coil. However, this method requires many rolling processes and a huge amount of rolling equipment, which increases equipment costs.Also, it requires heating the slab and controlling it to a constant temperature, which requires a large amount of heating. It is energy intensive and requires a large amount of rolling energy as it is necessary to roll from a thick slab to a thin hot coil.

Against this background, in recent years, continuous thin plate forming machines such as twin-roll type and endless track type (block type, belt type) have been developed that can directly produce thin metal sheets from molten steel. A continuous thin plate production facility has been proposed that allows rolled sheets to be rolled and finished to a predetermined thickness online.

[Problems to be Solved by the Invention] However, in such continuous thin plate manufacturing equipment, although rolling energy and heating energy can be reduced compared to when using the above-mentioned continuous slab casting machine, molten steel is produced in a blast furnace.
Because it is manufactured using the converter method, the initial cost of the furnace equipment accounts for a large proportion of the product cost, making it unsuitable for manufacturing general structural materials, building materials, and other components that do not require relatively high quality. Therefore, there are currently only a few examples of continuous thin plate manufacturing equipment being implemented.

[Means for Solving the Problems] The present invention was made in view of the above-mentioned circumstances, and uses an electric furnace, a twin-roll or trackless continuous sheet casting machine, and a hot tandem rolling mill, which is small in number. It is arranged and configured online.

[Operation] Therefore, a thin plate is cast from molten steel whose main raw material is scrap or reduced iron, whose composition has been adjusted, and then finish rolled in a hot rolling mill.

[Example] In Fig. 1, 1 is an electric furnace, and the electric furnace 1 produces molten steel 2 by melting scrap or reduced iron as the main raw material and adjusting the components (additives, vacuum degassing, etc.). It is something to do. 3 is a ladle for transporting the molten steel 2 produced in the electric furnace 1; 4 is a tundish for supplying the molten steel 2 received from the ladle 4 to the twin-roll Wuyun Ru machine 5; and 6 is a ladle for transporting the molten steel 2 produced by the continuous casting machine 5. An edge heater heats the end portion, 8 is a hot tandem finishing mill for finishing rolling the strip 7, 9 is a cooling device, 10 is a shear, and 11 is a winding machine, which are arranged in an on-line configuration.

In such a configuration, molten steel 2 is produced in an electric furnace 1 using scrap or reduced iron as the main raw material, but as refining technology has improved recently, it has been made considerably more expensive by performing vacuum degassing and adding additives. Quality molten steel 2 is obtained. This molten steel 2 is transported by a ladle 3 and transferred to a tundish 4, and is supplied from the tundish 4 to a continuous casting machine 5 through an immersion nozzle (Note 1). Then, continuous casting I! The strip 7 cast by J5 is heated by an edge heater 6 at its ends, which tend to radiate heat first, and passed through a finishing mill 8 at a uniform temperature in the width direction to be finished to a predetermined thickness. The strip 7 having a predetermined thickness is then passed through a cooling device 9.
The sheet is cooled by a shear 10, cut by a shear 10, and wound by a winder 11.

In this way, in the present invention, the molten steel 2 is produced using the small-scale electric furnace 1 instead of the blast furnace-converter method that requires large-scale equipment, so the strip 7 drawn from the continuous casting m, 5 is Although its uses are limited, it can achieve much lower costs than conventional methods. In addition, since the strip 7 produced by the continuous casting machine 5 is already a thin steel plate, compared to the manufacturing method using a conventional continuous slab casting machine,
A group of rough rolling mills is no longer required, and the number of stands for the finishing mill 8 can be significantly reduced, making it possible to efficiently and continuously manufacture thin steel sheets. Therefore, the running cost of the entire equipment is also reduced.

FIG. 2 shows another embodiment of the present invention, in which an endless track type (block type in the figure) continuous casting machine 5' is used instead of the twin roll Flf casting machine 50 in the previous embodiment, and the continuous The shear 10 is arranged downstream of the casting machine 5', and the number of stands of the finishing rolling mill 8 is appropriately reduced, and instead, the hot reverse rough rolling mill 8' is used for finishing rolling l11.
The configuration is such that it is incorporated at an upstream position of 8.

In the case of this method, since the strip 7 cast by continuous casting 1lls' is thicker than that in the case of continuous casting machine 5, rough rolling is performed in rolling 118', but otherwise the operation is the same as in the previous embodiment. It can be effective.

By the way, the energy consumption rate per ton of refined steel until molten steel is obtained is 3.8 million KC, al/in the case of the blast furnace-converter method.
lon, and if electricity is the law, 1.4 million Kcal /
It is lon.

It should be noted that the present invention is not limited only to the above-mentioned embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the present invention, molten steel is produced using scrap or reduced iron as a main raw material by an electric furnace method instead of the conventional blast furnace-converter method, and this molten steel is converted into an electric furnace. Casting is performed using a continuous casting machine located online, and then finished as a hot-rolled steel plate using a finishing rolling mill.
It is possible to achieve excellent effects such as downsizing the entire equipment, reducing initial costs and running costs, and ultimately reducing product costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a hot-rolled steel plate manufacturing facility of the present invention, and FIG. 2 is an explanatory diagram of another embodiment of the present invention. 1 is an electric furnace, 5 is a twin-roll continuous casting machine, 5' is an endless track continuous casting machine, 8 is a hot tandem finishing rolling machine, 8'
indicates a hot reverse rough rolling mill. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) An electric furnace that produces molten steel using scrap or reduced iron as a main raw material, a twin-roll continuous casting machine that casts a strip using the molten steel produced in the electric furnace, and the twin-roll continuous casting machine. 1. A hot-rolled steel sheet production facility characterized by an online arrangement of a hot finishing rolling mill for finishing a strip cast by a hot rolling mill to a predetermined thickness. 2) An electric furnace that produces molten steel using scrap or reduced iron as the main raw material, an endless track type continuous casting machine that casts strips using the molten steel made in the electric furnace, and a continuous track type casting machine that casts strips by the endless track type continuous casting machine. 1. A hot-rolled steel sheet production facility characterized by an online arrangement of a hot reverse rough rolling mill for rough rolling and a hot finishing mill for finishing the rough rolled strip to a predetermined thickness.