JP2854811B2 - In-line steel material production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-line steel material production facility for steel materials. More specifically, the present invention relates to a production facility combining a continuous casting machine and a rolling mill for producing steel materials such as steel bars, section steels, and wire rods.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional steel material production facility. 50 is a multi-strand continuous billet continuous casting machine,
A ladle 2, a tundish 3, a mold 4, a guide roll group 5, and a split shear 6 are provided. A rolling facility 10 is provided on a separate line from the square billet continuous casting machine 50, and includes a rough rolling mill 11, an intermediate rolling mill 12, and a finishing rolling mill 13. Note that a heating furnace 7 is provided on the entrance side of the rolling equipment 10, and a cooling floor 8 is provided on the exit side. In the conventional typical production equipment as described above,
In the case of producing a steel material, the square slab cast by the continuous billet continuous casting machine 50 is cut by the shear 6 and once cooled or directly conveyed to the rolling equipment 10 on another line. Then, after the slab is heated to a predetermined temperature in the heating furnace 7, the slab is rolled to a final product size by the rough rolling mill 11, the intermediate rolling mill 12, and the finishing rolling mill 13, and cooled in the cooling floor 8, followed by a refining process ( (Not shown).

[0003]

In the conventional square billet continuous casting machine 50, the production capacity per strand is reduced by the rolling equipment.
10 or less, the square billet continuous casting machine 50 must be multi-strand.
Could not be directly connected to. The reason for this will be explained with an example of a general-purpose round bar production equipment having a diameter of 10 to 51 mm and a production amount of Q = 60 tons / hour. In the conventional square billet continuous casting machine and equipment in which the mill line is separated, the billet material generally uses a square billet of □ 150 mm due to the relationship of the rolling ratio (see FIG. 4). □ The general casting speed of a 150mm square billet continuous casting machine is V = 2.5m / min, and the output per unit time per strand is Q = 26 tons / hour.
The number of strands for n = 60 tons / hour is n = 60/26 = 2.3
It becomes a strand, and a three-strand square billet continuous casting machine is required as equipment. On the other hand, even when a high-speed mold having a special shape (for example, Japanese Patent Application Laid-Open No. 4-319044) is used, the limit is V = 3.5 m / min. Q2 =
26 tons x 3.5 / 2.5 = 36.4 tons, requiring at least 2 strands, and it is impossible to connect square billet continuous casting machines and rolling equipment directly with square billets. Therefore, at present, the continuous billet continuous casting machine and the rolling equipment are separated from each other as shown in FIG.

In a continuous casting machine for a round billet, as disclosed in Japanese Patent Application Laid-Open No. 64-75145, a technique has been completed which prevents the occurrence of vertical cracks by improving the mold shape and improves the casting speed. Therefore, a production volume of 60 tons / hour is possible with an outer diameter of 242 mm and a casting speed V of 3.0 m / min. Also,
JP-A-64-75146 discloses an outer diameter of 228 mm and a casting speed of V.
= 3.3m / min, can produce 60 tons / hour. Therefore, it is conceivable that the continuous casting machine for round billets can be constituted by one strand and directly connected to rolling equipment. However, when the round billet manufactured by the round billet continuous casting machine is directly supplied to the two-roll type rough rolling mill 11 used in the conventional rolling equipment, the following problem occurs. That is, as shown in FIG. 5, when the round billet is directly rolled down by two rolls of the upper roll R1 and the lower roll R2, the upper and lower rolls R1,
Widening occurs to the side not in contact with R2 (arrow a), and immediately after casting with strong brittleness, if the amount of reduction is large, cracks c will occur on the side surface, the amount of reduction will be limited, and the number of stands of the rolling equipment will increase significantly. . In addition, it causes quality deterioration such as crack c on the side surface and dispersion of porosity p on the inner surface. Therefore, it is difficult to directly connect to a group of conventional rough rolling mills even if a heat retaining furnace for soaking is provided after casting to prevent rolling cracks. Therefore, conventionally, the yield, energy saving, labor saving, facility simplification, and running cost could not be further improved by any method.

The present invention has been made in view of the above circumstances, and has as its object to improve the yield, achieve energy saving and labor saving more than ever, and achieve a reduction in equipment space, equipment cost, and running cost accompanying simplification of equipment. I do.

[0006]

The in-line type steel material production equipment according to the present invention comprises a continuous caster for round billet strands, a four-roll mill, a rough rolling mill, an intermediate rolling mill and a finishing rolling mill. , On the same pass line,
It is characterized by being provided in that order. In the present invention, providing a heat retaining furnace is optional, and the heat retaining furnace is provided immediately before or immediately after the 4-roll mill.

[0007]

The round billet slab cast by the continuous casting machine for round billets is rolled down into a square billet by rolling down in four directions using a four-roll mill before being supplied to the rolling equipment. The rolling by the four-roll mill causes the width of the non-rolled portion to be narrowed by rolling in a manner opposite to that of the two-roll mill, and the width of the width is more remarkable as the rolling reduction is larger. Therefore, unlike the two-roll rolling, cracks due to the widening do not occur, and the porosity of the inner surface also sinks uniformly at the center, so that the quality can be greatly improved. Further, the rolling quality in the conventional rolling mill train following the 4-roll mill is improved, and the yield is improved. Therefore, the 4-roll mill and rolling equipment were arranged on the same pass line in accordance with the exit pass line of the strand of the continuous casting machine for round billets with high production capacity, and the continuous casting machine for round billets and the rolling mill row were directly connected. Because it can be configured as an in-line type, installation space, installation costs, and running costs can be reduced, and energy and labor savings during operation can be achieved.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of a steel material production facility according to one embodiment of the present invention, FIG. 2 is an explanatory view of a roll shape of a 4-roll mill 20,
FIG. 3 is an explanatory view of a square billet rolled by a four-roll mill 20.

In FIG. 1, reference numeral 1 denotes a continuous casting machine for round billets, which comprises a ladle 2, a tundish 3, a mold 4, a group of guide rolls 5, and a split shear 6, similarly to a known continuous casting machine. Of course, the mold 4 and the guide roll group 5 are dedicated to the round billet. In accordance with the exit pass line of the strand of the continuous casting machine 1 for a round billet, a heat preservation furnace 9, a roll mill 20, a rough rolling mill 11,
Rolling equipment 10 consisting of an intermediate rolling mill 12 and a finishing rolling mill 13
Are provided on the same pass line in that order. In addition, whether or not to provide the heat retaining furnace 9 is optional, but it is preferable to provide a material such as high carbon steel or special steel which needs to homogenize the temperature in the billet cross section due to rolling characteristics. The installation position may be immediately before or immediately after the 4-roll mill 20.

The four-roll mill 20 is not particularly limited to the driving type, roll shape, roll arrangement, etc., and various types can be used. Therefore, any of four-roll co-drive, parallel two-roll drive, two-roll idler, and four-roll non-drive may be used. 2 which is orthogonal to the parallel 2 roll
Rolls do not have to be on the same plane, about ± 100
The ones offset in the range of mm and those housed in the same housing are included in the four-roll mill according to the present invention. Further, the surface of the roll is not limited to the round billet, as shown in FIG.
), Convex (Fig. (B)), concave (Fig. (C)), with calipers (Fig. (D)), etc., as long as the billet after molding has a substantially square cross section. .

The rough rolling mill 11 and the intermediate rolling mill of the rolling equipment 10
12. The finish rolling mill 13 is the same as the conventional one, and is configured by arranging two-roll mills in multiple stages. However, regarding the finish rolling mill 13, JP-A-6-262201 and JP-A-6-262001 using a four-roll mill for the final stand.
-262202.

In the above-mentioned production equipment, the round billet (for example, φ220 mm) cast by the round billet continuous casting machine 1 is heated in the heat retaining furnace 9 and then sent in-line to the 4-roll mill 20 where the 4-roll mill 20 is heated. To a square billet (□ 160 mm), and then the square billet is sequentially reduced by rolling equipment 10 on the same line to finally produce a round bar steel product (φ10 mm).
~ 51mm). Although the above description is based on the production of round bar steel as an example, the same line is used to produce wire rods, square bar steel, shaped steel (equal angle angle steel, unequal angle angle steel, channel steel, etc.), flat steel, etc. it can. In this case, rolling equipment
What is necessary is just to change the roll shape of 10 into the shape matched with the shape of the final product.

When a round billet is rolled into a square billet by the 4-roll mill 20, as shown in FIG.
The non-rolled portions that are not in contact with the rolls R1, R2, R3, R4 cause a narrowing (in the direction of arrow d), and the amount of the narrowing increases as the rolling reduction increases. Therefore, crack c does not occur, and the internal porosity p sinks uniformly at the center, so that the quality of the slab is greatly improved. In addition, rolling equipment
The rolling quality at 10 is also good, and the product yield is improved.

In the case of the production facility of the present invention, since the rolling facility 10 is directly connected to the continuous casting machine 1, the installation space for the production facility is reduced, and
Since there is no need for a transfer device for transferring the cast slab or labor, it is possible to achieve equipment cost, energy saving and labor saving in operation.
Also, since a casting speed exceeding 3 m / min, which is the lower limit of the entry side speed of the first stage of the mill of the rolling equipment 10, can be obtained, no special measures are required for preventing thermal cracking of rolls used for low speed rolling. In addition, it is possible to connect with a continuous casting machine without greatly improving an existing rolling mill.

[0015]

According to the present invention, it is possible to improve the yield, save energy and labor more than ever, and reduce the equipment space, equipment cost, and running cost accompanying the simplification of equipment.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a steel material production facility according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a roll shape of a four-roll mill 20.

FIG. 3 is an explanatory view of a square billet rolled by a four-roll mill 20.

FIG. 4 is an explanatory view of a layout of a conventional steel material production facility.

FIG. 5 is an explanatory view of a problem when a round billet is rolled by a two-roll mill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuous casting machine for round billets 9 Heat retention furnace 10 Rolling equipment 11 Rough rolling mill 12 Intermediate rolling mill 13 Finish rolling mill 20 4 roll mill

Continuation of the front page (56) References JP-A-5-42304 (JP, A) JP-A-5-337510 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 1 / 00-1/06 B21B 1/16-1/20 B21B 1/46 B22D 11/12

Claims (2)

(57) [Claims] 1. A strand of a continuous casting machine for a round billet,
An in-line type steel material production facility, wherein a four-roll mill, and rolling facilities including a rough rolling mill, an intermediate rolling mill, and a finishing rolling mill are provided on the same pass line in that order. 2. The in-line steel material production facility according to claim 1, wherein a heat preservation furnace is provided immediately before or immediately after said four-roll mill.