JPS6192706A - Preventing method of local cooling in continuous hot rolling line - Google Patents

Abstract

PURPOSE:To prevent a rolling stock at the time of joining from local cooling by coating a heat insulating material on both of pinch rolls and table rolls located between a cradle and a looper in a titled line for joining preceding and succeeding rolling-stocks together in sequence. CONSTITUTION:A rough rolled stock rolled by a roughing mill is wound up by a winder 1 and is transferred as a coil 2 to >=2 sets of cradles 3, and is sent to a joining machine 4 by unwinding it from the cradle 3. the rear end of a preceding stock 5a and the front end of a succeeding stock 5b are joined together by the machine 4, and both stocks are continuously sent to a finishing mill through a looper 6. In this continuous hot rolling line, heat insulating materials are coated on pinch rolls 7 and table rolls 8 located between the cradle 3 and the looper 6, respectively. As a heat insulating material to be coated, Al2O3, ZrO2, WC, etc. or the mixture of them can be used; and as a coating method, the material is coated on the whole surface of roll or on the roll surface at fixed intervals, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Field of Application The present invention is directed to a continuous hot rolling line in which the trailing end of a preceding rolled material and the leading end of a trailing rolling material are successively joined and rolled continuously. The present invention relates to a method for preventing local cooling of rolled material.

(b) Prior art In recent years, continuous hot rolling has been proposed in order to improve threadability, reduce scrap loss, and improve work efficiency. In this continuous hot rolling, the rear end of the preceding rolled material and the leading end of the succeeding rolled material are joined by welding or the like between a rough rolling mill and a finishing rolling mill, and finish rolling is performed continuously. It is something.

A typical conventional continuous hot rolling line to which the method of the present invention is applied will be explained with reference to FIG. A rough rolled material rolled by a rough rolling mill (not shown) is wound into a coil shape by a winding P91. A coil 2 of roughly rolled material is transferred from the winder 1 onto a cradle 6, from which it is rewound and sent to a splicer A. In the welding machine 4, the rear end of the leading material 5a and the leading end of the trailing material 5b are joined, and are continuously sent through a looper 6 to a finishing mill (not shown).

In such a continuous hot rolling line, when the rolled materials are joined by the joining machine 4, the rolled materials are kept stationary for a short period of time (about 10 seconds). At this time, the rolled material is stopped while being clamped by the crater, pinch roller, table roller, clamper, etc., so the rolled material is locally cooled (approximately 150 to 200℃). (to a lesser extent).

This local cooling causes a decrease in the dimensional accuracy of the thickness and width of the rolled material during finish rolling, as well as a decrease in quality.

(c) Problem to be solved by the invention The problem to be solved by the present invention is to prevent local cooling of the rolled material when joining the rolled material by a joining machine in a continuous hot rolling line. It is in.

B) Means for solving the problem The method for preventing local cooling of rough rolled material of the present invention is to install an in-line coiler between the exit side of the rough rolling mill and the input side of the finishing rolling mill in a continuous hot rolling line. The in-line coiler is provided with a small (both 2
providing a cradle for a table; sending the rough rolled material to the finishing rolling mill while unwinding the coil by the cradle; and providing a joining machine on the exit side of the cradle to connect the rear end of the preceding rolled material to the trailing rough rolling. A looper is provided on the outlet side of the welding machine to adjust the feed rate of the rough rolled material, and a pinch roll and a pinch roll are arranged between the cradle and the looper. The above problems are solved by applying a heat insulating phase coating to the table roller.

The present invention can also solve the above-mentioned problems by providing heat insulating plates that surround the rough rolled material at various locations between the cradle and the gutter in the continuous hot rolling line.

The present invention can further prevent local cooling by enclosing the heat insulating plate in addition to the heat insulating coating.

(E) Example An example of the method of the present invention will be described with reference to FIG. The continuous hot rolling line is as described above. In the figure, reference number 7 is a pinch roll, 8 is a table roller, and 9 is a clamper.

In the method of the present invention, a pinch roll 7 and a table are arranged between the cradle 6 and the looper 6.
Apply a heat insulating coating to the roller 8. As insulation materials, alumina (A1203), Zirco=7 (ZrO2)
, rim sulfide (Gr20s), tungsten carbide (
vr G ) or a mixture thereof can be used.

As shown in Fig. 2, methods for coating the heat insulating material include a method (A) in which the entire roll surface is coated;
A method of coating at regular intervals (B), a method of spirally coating at a constant pitch (C),
Alternatively, there is a method (D) in which the coating is applied in a staggered manner.

In order to prevent local cooling by the clamper 9, it is preferable to provide a heat insulating material on the gripping surface of the clamper 9.

Furthermore, in the method of the present invention, as shown in FIG. 3, heat insulating plates 10 surrounding the rough rolled material are provided at various locations between the cradle 6 and the looper 6 (FIG. 1). As the heat insulating board, a molded heat-resistant board, a rock wool product, an unshaped refractory material, etc. can be used.

Although it is sufficient to provide the heat insulation plates 10 on the top and bottom of the rough rolled material, the heat retention effect can be increased by providing them on the left and right sides, that is, the side surfaces, of the rough rolled material. The heat insulating plate 10 also functions as a guide for the rough rolled material.

Furthermore, in the method of the present invention, by combining the method of using a heat insulating plate with the method of coating a heat insulating material,
Local cooling can be prevented even more effectively.

(f) Effects In the conventional method, local cooling of 150 to 200°C occurred, but according to the heat insulating material coating method of the present invention, local cooling of 10 to 60°C occurred.
It can be reduced to 20°C or more depending on the method of using a heat insulating plate. io'
GK can be reduced by 10 to 10% using a method that uses both of them together.
The temperature could be reduced to 20°C. As a result, the width and dimensional accuracy of the finished product can be improved and the quality can be made more homogeneous.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of continuous hot rolling equipment for carrying out the method of the present invention. Figure 2 shows the pinch and
A perspective view of a roll or table roller. FIG. 3 is a schematic explanatory diagram of another continuous hot rolling facility for carrying out the method of the present invention. 1: Winder 2: Coil 3: Cradle A: Joiner 5a: Leading material 5b: Following material 6: Luno ξ 7: Pinch roll 8: Table roller 9: Clamper 10: Heat insulation plate (external name)

Claims (3)

[Claims] (1) In a continuous hot rolling line, an in-line coiler is provided between the outlet side of a rough rolling mill and the inlet side of a finishing rolling mill to wind the rough rolled material into a coil shape, and the in-line coiler At least two cradles are provided on the side, the rough rolled material is sent to the finishing mill while the coil is unwound by the cradle, and a welding machine is provided on the exit side of the cradle to connect the rear end of the previously rolled material to the finish rolling mill. A looper is provided on the exit side of the welding machine to adjust the feed rate of the rough rolled material, and the looper is disposed between the cradle and the looper. A method for preventing local cooling of rough rolled material, which comprises applying a heat insulating coating to pinch rolls and table rollers. (2) In a continuous hot rolling line, an in-line coiler is provided between the outlet side of a rough rolling mill and the inlet side of a finishing rolling mill to wind the rough rolled material into a coil shape; At least two cradles are provided on the side, the rough rolled material is sent to the finishing mill while the coil is unwound by the cradle, and a welding machine is provided on the exit side of the cradle to connect the rear end of the previously rolled material to the finish rolling mill. The steps include sequentially joining the leading ends of the trailing rough-rolled material, providing a looper on the outlet side of the welding machine to adjust the feed rate of the rough-rolled material, and moving the rough-rolled material between the cradle and the looper. A method for preventing local cooling of rough rolled material, which consists of providing surrounding heat insulating plates at various locations. (3) In a continuous hot rolling line, an in-line coiler is provided between the outlet side of a rough rolling mill and the inlet side of a finishing rolling mill to wind up the rough rolled material into a coil; At least two cradles are provided on the side, the rough rolled material is sent to the finishing mill while the coil is unwound by the cradle, and a welding machine is provided on the exit side of the cradle to connect the rear end of the previously rolled material to the finish rolling mill. sequentially joining the leading ends of the trailing rough rolled material; providing a looper on the exit side of the welding machine to adjust the feed rate of the rough rolling material; and a pinch disposed between the cradle and the looper. - A method for preventing local cooling of rough rolled material, which comprises applying a heat insulating coating to the roll and table roller, and providing heat insulating plates surrounding the rough rolled material at various locations between the cradle and the looper.