JP2002224708A - Continuous hot rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous hot rolling method capable of transferring sheet bars always with suitable temperature for finish rolling to a finishing mill. SOLUTION: The sheet bars are jointed at a jointing device 80, heated at reheating devices 10 for their whole width and rolled at the finishing mill 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot rolling method in which rough-rolled sheet bars are joined and finish-rolled continuously.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing an example of a conventional apparatus, showing the concept of a finishing rolling mill line of a continuous hot rolling facility, and FIG. 6 shows a temperature drop of a sheet bar to a finishing rolling mill. FIG.

As shown in FIG. 5, a coil 50 wound on an entrance cradle roll 62a in a heat retaining cover 61 of a coil box 60 is transferred to an exit cradle roll 62b by an arm 63 and rewound, and is pinched. Conveyed by 69. Then, after the tip crop is cut by a crop shear 70, the sheet bar 51 is conveyed to a finishing mill 90 by a pinch roll 89, and is hot-rolled sequentially to a required thickness by the finishing mills 90 of the plurality of stages.

When the rewinding of the coil 50 is completed, the rear end crop of the sheet bar 51 is removed by a crop shear 70.
When the rear end comes to the exit clamp 83 of the joining device 80, the joining device 80 is moved from the most upstream part (left side in FIG. 5) of the rail 87 by the bogie 82 at the same speed as the traveling of the seat bar 51. While being clamped.

At the same time, the coil 5 wound and stored on the entry cradle roll 62a in the coil box 60 is stored.
0 is transferred onto the output side cradle roll 62b by the arm 63 and rewound. The transport speed of the rewound sheet bar 51 is increased by the pinch roll 69, and the leading end crop is cut by the crop shear 70 to move the sheet bar 51. To the joining device 80, and the leading end thereof is joined to the joining device 8.
It is fixed with a zero input side clamp 86. Then, the front end of the succeeding sheet bar 51 and the rear end of the preceding sheet bar 51 already fixed by the output side clamp 83 are heated to a required joining temperature by the heater 84 of the joining device 80, and the entrance side clamp is heated. 86 is moved in the housing 81 of the joining device 80, and the leading end of the succeeding sheet bar 51 is pressed against the trailing end of the preceding sheet bar 51 for joining.

[0006] In this way, the sheet bars 51 are joined one after another by the joining device 80, and finish rolling is continuously performed by the finish rolling machine 90.

[0007]

However, in the conventional continuous hot rolling equipment, a long space is required because the joining device 80 that travels a long distance on the entry side of the finishing mill 90 is arranged.

For this reason, especially the sheet bar 51 having a small thickness is used.
In a sheet bar 51 having a low running speed, the finishing mill 90
As shown in FIG.
1 is lower than the temperature required for hot rolling (approximately 1050 ° C.), that is, the temperature at which the exit temperature of the finishing mill 90 is equal to or higher than the Ar3 transformation point. In the example of FIG. 6, when the sheet bar 51 has a thickness of 15 mm and a traveling speed of 32 mpm, the sheet bar 51, which was 1100 ° C. when unwound by the coil box 60, is joined by the joining device 80 to finish rolling mill. The temperature is lowered to about 860 ° C. before being conveyed to 90, which hinders hot finish rolling.

Accordingly, an object of the present invention is to provide a continuous hot rolling method capable of always conveying a sheet bar to a finishing mill at a temperature suitable for hot finish rolling.

[0010]

A continuous hot rolling method according to the present invention is characterized in that sheet bars are joined, the entire width of the sheet bars is heated, and then finish rolling is performed.

The heating of the entire width of the sheet bar by the induction heating is suitable in terms of rapid heating and heating control accompanying a change in sheet thickness.

According to the above construction, the rear end portion of the preceding sheet bar and the front end portion of the succeeding sheet bar are joined by the sheet bar joining device, and the temperature is lowered to a required temperature at the entrance of the finishing mill. Then, the temperature is raised to a temperature required for hot finish rolling by a sheet bar heating device, and finish rolling is performed to a required thickness by a finish rolling mill.

In this manner, the rear end of the preceding sheet bar and the front end of the succeeding sheet bar, which are successively conveyed, are joined by the sheet bar joining device, heated by the sheet bar heating device, and subjected to hot finish rolling. Hot rolling is continuously performed on a strip of a required thickness by a finishing mill while adjusting to an optimum temperature.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the continuous hot rolling method according to the present invention will be described in detail with reference to examples.

FIG. 1 is a side view showing the concept of a continuous hot rolling facility applied when carrying out the continuous hot rolling method of the present invention, and FIG. 2 is an enlarged plan view of the heating device of FIG. Figure,
FIG. 3 is a sectional view taken along line III-III of FIG. Note that the same members and devices as those of the conventional apparatus shown in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, a heating device 10 using an induction heating coil is disposed between a joining device 80 and an input pinch roll 89 of a finishing mill 90. As shown in FIGS. 2 and 3, the heating device 10 is disposed between the table rollers 30, and is mounted so that the traveling sheet bar 51 passes through the induction heating coil. Other configurations are the same as the conventional equipment.

With this configuration, the coil bar 50 that has been roughly rolled and wound on the entrance cradle roll 62a in the coil box 60 is transferred onto the exit cradle roll 62b, and then unwound. Is transported by a pinch roll 69, and the tip crop is
And cut straight.

If the temperature of the sheet bar 51 is lower than the temperature required for hot rolling (about 1050 ° C.), the heating device 1
0 to adjust the temperature,
9 and is conveyed to a finishing mill 90, and hot-rolled to a required thickness sequentially by the multistage finishing mill 90.

In the illustrated example, an edge heating device 40 is provided between the heating device 10 and the pinch roll 89 to heat the edge portion of the sheet bar 51 which cools faster than the center portion.

When the rewinding of the coil 50 is completed, the rear end crop of the sheet bar 51 is removed by the crop shear 70.
When the rear end reaches the exit clamp 83 of the joining device 80, the joining device 80 is moved from the most upstream portion (left side in FIG. 1) of the rail 87 by the bogie 82 at the same speed as the traveling of the seat bar 51. While running, it is fixed with the output side clamp 83.

At the same time, the coil 5 wound and stored on the entry cradle roll 62a in the coil box 60 is stored.
0 is transferred onto the output side cradle roll 62b to start rewinding. The sheet bar 51 is conveyed at a high speed by a pinch roll 69, and the leading end crop is cut by a crop shear 70 to travel the joining device 80. And the front end thereof is fixed by the entry side clamp 86 of the joining device 80.

Then, the leading end of the succeeding sheet bar 51 and the rear end of the preceding sheet bar 51 which has already been fixed are heated to a required joining temperature, and the entrance clamp 86 is moved in the housing 81 and The leading end cut portion of the sheet bar 51 is pressed and joined to the trailing end cut portion of the preceding sheet bar 51.

If the temperature of the sheet bar 51 is lower than the temperature required for hot rolling (about 1050 ° C.), the heating device 10 heats the sheet bar 51 over the entire width thereof to adjust the temperature. Then, it is conveyed by a pinch roll 89 to a finishing mill 90, and hot-rolled to a required sheet thickness sequentially by the multistage finishing mill 90.

In the example of FIG. 4, the thickness of the sheet bar 51 is 1
When the traveling speed is 5 mm and the traveling speed is 32 mpm, the temperature of the sheet bar 51, which was 1100 ° C. when rewound by the coil box 60, drops to about 860 ° C. at the entrance of the heating device 10. ° C, and drops to 1059 ° C, which is optimal for hot rolling, when the roll is engaged in the finishing mill 90.

In this way, the sheet bars 51 are successively joined by the induction heating by the joining device 80, and are finish-rolled continuously by the finish rolling mill 90.

The present invention is not limited to the above embodiment,
It goes without saying that various changes can be made without departing from the spirit of the present invention.

[0027]

According to the present invention, the sheet bar is joined, the entire width of the sheet bar is heated, and then the finish bar is rolled. Therefore, a sheet bar joining apparatus having a long running distance is arranged for continuous hot rolling. Despite the increased distance to the finishing mill, no matter how thin the sheet bar or its traveling speed is, the bonded sheet bar is required for hot finish rolling by a sheet bar heating device. Can be adjusted to temperature. Therefore, continuous hot finish rolling of the sheet bar can be always performed stably, and a high quality strip can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a concept of a continuous hot rolling facility applied when performing a continuous hot rolling method of the present invention.

FIG. 2 is an enlarged plan view of the heating device of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a diagram showing a temperature drop of a sheet bar to a finishing mill and a temperature rise by a heating device.

FIG. 5 is a side view showing the concept of a conventional general continuous hot rolling facility.

FIG. 6 is a diagram showing a temperature drop of a sheet bar to a finishing mill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Heating apparatus 40 Edge heating apparatus 50 Coil 51 Sheet bar 60 Coil box 70 Crop shear 80 Joining apparatus 90 Finishing mill

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K059 AA08 AB17 AB19 AB26 AB28 AD03 AD13 AD15 CD62 CD66 CD72 CD75 4E002 AD01 BD05 BD08

Claims (2)

[Claims] 1. A continuous hot rolling method comprising joining a sheet bar, heating the entire width of the sheet bar, and finish-rolling the sheet bar. 2. The continuous hot rolling method according to claim 1, wherein the entire width of the sheet bar is heated by induction heating.