JP3401143B2 - Slab supply method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to a slab supply method.

[0002]

2. Description of the Related Art As a slab supply yard for a slab transported to a hot rolling plant, a slab supply route to a heating furnace that heats a slab having a relatively high temperature to a rolling temperature and a slab supply yard from a cold piece storage yard A supply route to the heating furnace that heats the low-temperature slab to the rolling temperature is provided, and the slab supply pitch to the heating furnace is adjusted according to the relationship between the amount of slab (heating time) charged to each heating furnace and the rolling capacity. The adjustment of the ratio is disclosed in Japanese Patent Laid-Open No. 3-106501.

[0003]

The slabs after continuous casting are roughly classified into maintenance slabs and unmaintained slabs among rolled slabs, and maintenance slabs and unmaintained slabs among cold preservation slabs. Such casting slabs are generally mixed and cast in continuous casting, sorted after continuous casting, unmaintained slabs are fed into a heating furnace and heated to the rolling temperature, and maintenance slabs have surface defects, etc. In order to carry out maintenance by melting and removing the steel, it is transferred to a hot scarf facility, cleaned, and then transferred to a heating furnace and heated to the rolling temperature. In addition, the unmaintained slab in the cold piece storage slab is carried into the cold piece slab yard, and the maintenance slab is subjected to maintenance to melt and remove surface flaws, etc.
Carry it into the cold slab yard and store it. However, sorting of slabs on the continuous casting outlet side or hot rolling mill entrance side requires sorting by a hoist, forklift, etc. while transporting them, which requires a large amount of manpower and reduces work efficiency, resulting in poor productivity. Is also having an adverse effect. Further, in the hot rolled slab yard, the temperature of the slab is lowered by staying for a long time while waiting for the rolling unit formation. In addition, the slabs are stacked, and the temperature does not drop so much due to the heat retention effect, but the number of stacked slabs is reduced due to the rolling unit knitting, and it is possible to tie and stack with low temperature slabs that have stayed for a long time. Causes the temperature to drop. Furthermore, the unit amount of the rolling lot cannot be secured and the temperature is lowered by staying for a long time, so that the heating time becomes long, the productivity is lowered, and the energy cost is increased. Further, if slabs having different temperatures are mixed and heated, it becomes difficult to uniformly bring the slabs to the rolling temperature, which causes problems such as deterioration in shape after rolling and adversely affecting quality. The present invention has been made for solving such a problem advantageously eliminates the crossing of slab transport, yet uniform by reducing the temperature difference between the reduced and chromatic care slabs and no care slabs of the slab temperature it is an object to provide a Luz Rab supply method can of be heated to the rolling temperature.

[0004]

A feature of the present invention is that a continuously cast slab is divided into a rolling slab and a cold piece storage slab, and each divided slab is classified into a maintained slab and an unmaintained slab. Then, the pallets are loaded separately into pallets according to their classification, and then the loaded and loaded pallets are transported to the pallet yard of the hot rolling factory by a self-propelled trackless truck, giving priority to the maintenance slabs in the rolling slabs.
After carrying out and carrying out maintenance on the maintenance line,
Thereby transferring Rab conveying line, the free care slab during rolling the slab, the heating furnace through a non-clean slab transport line, care has been perforated care slab and hot strip at 100 ° C. or less temperature difference no care slab It is a slab supply method characterized by charging a slab and heating it to a rolling temperature.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION When hot-rolling a continuously cast slab in a hot rolling plant which is the next hot rolling step, generally, the slab after casting is charged into a heating furnace at about 800 ° C. and then rolled. It is heated to a suitable temperature of 1200 to 1300 ° C. and supplied to a hot rolling line. So-called hot charge rolling is performed to save energy and improve the heating furnace capacity by charging at high temperature. In continuous casting, however, one charge of molten steel refined in a steelmaking furnace is poured into a ladle and the ladle filled with molten steel is replaced, while continuous casting is performed. Few. Therefore, among the cast slabs for one charge of molten steel, there is a cold strip storage slab that is rolled into a product and carried into a cold strip slab yard at a hot rolling plant and stored until a customer receives an order. . In addition, among such rolling slabs and cold piece storage slabs, slabs that become unmaintained slabs after casting and surface defects due to various factors during casting, surface cracks during casting, etc. Mixed maintenance slabs that require surface care.

[0006] Thus, the slabs are cast by the continuous casting device, and the various slabs as described above, which are cut into a predetermined length, are moved to, for example, a carry-out yard adjacent to the continuous casting device, sorted, and sorted into pallets according to classification. . In addition to such classification, for example, C: 0.0002 to 0.008% ultra low carbon steel and C: 0.02 to 0.10% low carbon Al killed steel are classified and stacked to obtain hot rolling. It is preferable because the heating temperature in the heating furnace of the factory can be precisely controlled.

The pallets with the slabs thus stacked are loaded on a self-propelled trackless carriage and carried into a yard on the entry side of a hot rolling mill in the next process, and first, the cared slab in the rolling slab is, for example, the surface flaw position. After carrying out to a maintenance line consisting of a detector, hot scarf device and grinder to remove surface flaws, etc., it is carried out to a maintenance-free slab transfer line by a transfer device such as a hoist or turntable and heated. After being charged into a rolling mill and heated to the rolling temperature, it is supplied to a rolling line consisting of a rough rolling mill and a finish rolling mill. On the other hand, at the same time, the unmaintained slab in the rolling slab is carried out from the pallet yard to the unmaintained slab transfer line, similarly charged into the heating furnace, heated to the rolling temperature, and then supplied to the rolling line. Since the temperature of the slab being conveyed is lowered, it is possible to effectively prevent the temperature from being lowered by, for example, covering the stacked slab with a heat insulating box.

As described above, by preferentially carrying out the maintenance slab to the maintenance line and cleaning the slab surface flaws, the waiting time in the pallet yard is reduced to prevent the temperature of the slab from decreasing as much as possible, and the maintenance-free slab is maintained. The temperature difference between and. In other words, the temperature of the maintenance slab decreases as much as the time it takes to maintain it.Therefore, the waiting time in the yard should be kept as short as possible and the slab temperature should be reduced by shortening the maintenance time to prevent the slab from decreasing in temperature. The temperature difference between the maintained slab and the unmaintained slab can be 100 ° C. or less, can be uniformly heated in the heating furnace, and can prevent deterioration of the shape during rolling. Further, even if the maintenance slab and the unmaintenance slab are mixed in the heating furnace, the temperature is high and the temperature difference is small, so that the heating time can be shortened, productivity can be improved, and energy saving can be achieved. .

On the other hand, the unmaintened slab in the cold piece storage slab is transported from the pallet yard to the cold piece slab yard and stored for waiting for an order. In addition, the maintenance slab in the cold piece storage slab is carried out from the yard to the maintenance line, after the slab surface flaws are cleaned, transferred to the slab forced cooling line by the transfer device and cooled to almost room temperature, Carry it into the cold slab yard and wait for an order.

[0010]

EXAMPLES Next, examples of the present invention will be described. In FIG. 1, a continuous casting apparatus 1 casts a slab, and the slab is moved from a strand table 2 and 2a through a traverse car 3 to a weighing machine 4 and weighed, and then a slab surface flaw inspection apparatus 5 is used to remove surface flaws. When the slab is inspected and then carried out by the slab lifter 6 through the slab pedestal 7 to the slab unloading yard 8, it is classified into a rolling slab and a cold piece storage slab,
Further, these slabs are sorted according to the slab width of the maintenance slab and the unmaintenance slab and the rolling unit, and then the slabs having a surface temperature of about 800 ° C. are pallets 9, 9a, 9b, 9
Each of them is loaded separately in c. The pallet 9d, among the other pallets 9, 9a, 9b, 9c, quickly fills the necessary amount for transportation to the yard of the hot rolling mill, and then quickly
One is always kept in standby as a spare so that it can be loaded in d. Then, the pallet 9 ...
Are sequentially mounted on the self-propelled track-free trolleys 10, 10a, 10b, 10c and transported to the pallet yard of the hot rolling factory.

That is, as shown in FIG. 2, the pallet yard 11 on the inlet side of the hot rolling factory is carried in, and at this yard 11, the maintenance slab (about 800 ° C.) in the rolling slab is preferentially connected to the yard 11. To the maintenance line 12 and at the same time to the maintenance-free slab transfer line 14 in which the maintenance-free slab (about 800 ° C.) in the rolling slab is arranged between the heating furnace 13, 13a, 13b, 13c charging side and the pallet yard 11. After unloading, the slabs are sequentially charged into the heating furnaces 13, 13a, 13b, 13c and heated to a rolling temperature of 1250 ° C., and then extracted and passed through the table 15 to the rough rolling mill 16 and the finish rolling mill 17.
Is supplied to the rolling line 18. On the other hand, the maintenance slab in the rolling slab carried out to the above-mentioned maintenance line 12 confirms the surface flaw position with the surface flaw position detector 19, and removes the surface flaw with the hot scarf 20, and then the surface flaw inspection device. After the presence or absence of residual flaws is inspected at 21, the residual flaws are removed by a grinder 22 if necessary, and a slab transfer device 24 provided between the maintenance-free slab transfer line 14, the maintenance line 12 and the slab forced cooling line 23. (Hoist) Transfers the slab whose temperature has dropped to 750 ° C to the maintenance-free slab transfer line 14 and transfers it to the heating furnaces 13, 13a, 13b, 13c together with the maintenance-free slab to the rolling temperature (1250 ° C). After heating, it is supplied to the rolling line 18.

Unmaintened slabs in the cold piece storage slab carried into the pallet yard 11 are carried into the cold piece slab yard 27 through the cold piece slab transport line 25 and are on standby for orders. On the other hand, the maintenance slab in the cold piece storage slab is carried out from the pallet yard 11 to the maintenance line 12, and as described above, the flaw position is detected by the surface flaw position detection device 19, the surface flaw is removed by the hot scarf 20, and the residual flaw inspection is performed. After inspecting the residual flaws with the device 21, if necessary, grinder 22
To remove the residual flaws, and then the slab transfer device 24
After being brought into the slab forced cooling line 23 and rapidly cooled to almost room temperature by water cooling, it is re-inspected at the inspection line 26 and properly cared for, and brought into the cold piece slab yard 27 to wait for an order.

[0013]

According to the present invention, the slabs after continuous casting are sorted and sorted in advance, the slabs are stacked on a pallet, and the slabs are conveyed to the hot rolling factory in the next step . For example, the maintenance line 12, unmaintained slab transfer
Line 14, slab forced cooling line 23, slab transfer equipment
Since the slabs are processed and supplied to the rolling line in the yard configured on the processing route such as the equipment 24 and the inspection line 26 , the cold piece storage slabs are carried into the cold piece slab yard, so there is almost no crossing of the slabs. In addition, the maintenance
Prioritize the removal of the slab to the maintenance line to remove the slab surface
By putting it in, the waiting time in the pallet yard
Minimize to prevent temperature drop of slab as much as possible
The temperature difference between and can be reduced. Therefore, there is no large variation in the slab temperature decrease during heating, the rolling temperature can be uniformly heated, the rolling shape can be improved, and the yield can be increased. Further, the slab can be reliably supplied, the rolling lot unit volume can be expanded and knitted, the productivity can be improved, and the labor can be saved. Furthermore,
Energy savings can be measured. Furthermore, by stacking the slabs after continuous casting on pallets and transporting them to a hot rolling plant, it is possible to prevent the reduction of rolling unit amount due to the maintenance slabs that occur during continuous casting and the reduction of heating furnace capacity due to temperature decrease. In addition, in the slab yard of the hot rolling mill, it is possible to omit the work of rearranging and supplying work for each rolling unit, and it is possible to obtain an excellent effect that the personnel can be significantly rationalized.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the present invention.

FIG. 2 is a flow chart showing an embodiment of the present invention.

[Explanation of symbols] 9 pallets 9a pallet 9b pallet 9c pallet 11 yards 12 Care line 13 heating furnace 13a heating furnace 13b heating furnace 13c heating furnace 14 Maintenance-free slab transfer line 23 Slab forced cooling line 24 Slab transfer device 26 inspection lines 27 Cold Slab Yard

Front page continuation (56) References International publication 96/12572 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21B 39/00 B21B 39/02 B21B 45/00 B22D 11 / 12 B65G 47/46 B21B 1/00-11/00

Claims (2)

(57) [Claims] 1. A continuous casting slab is divided into a rolling slab and a cold piece storage slab, and each divided slab is classified into a maintenance slab and a non-maintenance slab, which are loaded into a pallet according to each classification and then loaded. Separately loaded and loaded pallets are transported to the pallet yard of the hot rolling factory by a self-propelled trackless trolley, and the maintenance slab in the rolling slab is maintained.
After carrying out and performing maintenance on the maintenance line,
Thereby transferred to clean slab transfer line, thermally non care slab during rolling the slab, the heating furnace through a non-clean slab transport line, the temperature difference between the care already closed care slab and no care slab at 100 ° C. or less A slab supply method comprising charging a single slab and heating it to a rolling temperature. 2. The uncleaned slab of the cold piece storage slab is transported from the pallet yard to the cold piece slab yard, and
Caring for cold storage slabs Remove slabs to the maintenance line
After groomed, slab supply method according to claim 1 which is transferred to the slab forced cooling line with forced cooling, characterized in that for conveying the cold strip slab yard.