JPH03106501A - Hot rolling device - Google Patents

Abstract

PURPOSE:To improve the efficiency of a heating furnace by automatically adjusting the ratio of the pitch of the slab charged into 1st and 2nd heating furnaces according to the quantity of the slab fed from a continuous casting machine by a transfer control means and the size relation of the accession capacity of the 1st and 2nd heating furnace. CONSTITUTION:A transfer control means CPU automatically adjusts the ratio of the pitch with which a slab is charged into the 1st heating furnace and the pitch with which the slab is charged into the 2nd heating furnace, according to the size relation of the quantity of the slab delivered from plural continuous casting machines CCI, etc., and the accession capacity of the 1st heating furnace HH and the size relation of the heated slab quantity of the 1st heating furnace HH and 2nd heating furnace HL and the rolling capacity of a rolling device. Thus the generation of an empty space inside the 1st heating furnace accompanied by the fluctuation of the slab quantity is prevented and the reduction of the efficiency in the heating furnace HH can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hot rolling apparatus, and more particularly to a system for rolling hot pieces obtained from equipment including a plurality of continuous casting machines and a plurality of heating furnaces. Prior Art] A conventional device for rolling a slab produced from a continuous casting machine is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 59-101205 and 1982-131652. This type of equipment is constructed so that the slab discharged from the continuous casting machine is passed through a heating furnace and heated to a predetermined rolling temperature, and then transported into the rolling mill. [Jl! Problem that Ming is trying to solve] In hot rolling equipment, the sooner the slab from the continuous casting machine is charged into the heating furnace, the lower the temperature drop of the slab will be, and therefore the time required for heating in the heating furnace will be reduced. This also saves heating energy. By the way, in order to respond to fluctuations in the operating rate of continuous casting machines and fluctuations in the amount of orders for rolled products, when the operating rate of continuous casting machines is high, it is necessary to produce slabs in quantities that exceed the processing capacity of the rolling mill and heating furnace. There is a need. Conventionally, the slabs that come out of the continuous casting machine are divided into hot slabs and cold slabs, the hot slabs are directly transported to a heating furnace and heated, and then passed through a rolling mill, while the cold slabs are sent to a designated slab storage area. When the required rolling amount increases, the cold pieces are heated and rolled in parallel with the hot pieces. Furthermore, when both hot and cold pieces are heated and rolled, the hot and cold pieces are alternately charged into a heating furnace and processed. However, when using multiple continuous casting machines, if some of the continuous casting machines are stopped, the operating rate of the entire casting machine changes significantly, and the amount of slabs supplied to the heating furnace changes significantly. When charging hot slabs and cold slabs into the heating furnace alternately at a constant pitch, for example, due to a decrease in the casting pitch (stopping the casting machine, etc.), it is necessary to charge the hot slabs this time at the timing of charging the hot slab slab. If the hot pieces do not arrive at the inlet side of the furnace, an empty space will be created in the heating furnace, the energy efficiency of the heating furnace will decrease, and wasteful fuel consumption will increase. Conversely, if a large number of slabs arrive before the hot slab charging timing, the temperature drop of the slabs while waiting before charging increases, and in this case also, energy efficiency decreases.

In addition, the extraction pitch when extracting slabs from the heating furnace and supplying them to the rolling mill changes according to changes in the processing capacity of the rolling mill and changes in the slab material, so the processing capacity (heating capacity) of the heating furnace changes. Even if is constant, the slab receiving capacity of the heating furnace changes. Therefore, for example, if the amount of slab supplied is less than the receiving capacity of the heating furnace, the energy efficiency of the heating furnace will decrease.

The present invention aims to make it possible to adjust the rolling amount in response to changes in the order volume of rolled products, and to reduce the decrease in energy efficiency of the heating furnace due to changes in the operating rate of the continuous casting machine. Suppose that [Means for Solving the Problems] In order to solve the above problems, the present invention includes a plurality of continuous casting machines; a cold slab storage area; Heating furnace: A second heating furnace that heats the comparatively low-temperature slabs coming out of the cold piece storage area to a predetermined rolling temperature; A second heating furnace that transports the slabs obtained by the continuous casting machine and transfers the slabs to the first A conveyance mechanism that carries the slabs into the heating furnace or into the second heating furnace via the cold piece storage area; sequentially transports the slabs coming out of the first heating furnace and the slabs coming out of the second heating furnace; a rolling device that receives and rolls the slabs; and controls the conveyance mechanism to determine the magnitude relationship between the amount of slabs delivered from the plurality of continuous casting machines and the receiving capacity of the first heating furnace, and the first and second heating The ratio of the pitch at which slabs are charged into the first heating furnace and the pitch at which slabs are charged into the second heating furnace is automatically determined depending on the magnitude relationship between the amount of heated slabs in the furnace and the rolling capacity of the rolling device. A conveyance control means is provided to adjust the [Function] In the present invention, the first heating furnace is used as a heating furnace exclusively for hot pieces, and the second heating furnace is used as a heating furnace only for cold pieces. The time required to heat hot pieces to the specified rolling temperature and the time required to heat cold pieces to the specified rolling temperature are significantly different, so if they are processed simultaneously in the same furnace, the time required to heat the hot pieces will be longer. Although it is longer and more wasteful, by heating the hot and cold pieces in separate dedicated heating furnaces, it is possible to heat the hot and cold pieces at the same time. For example, in order to maintain a constant rolling amount, the charging pitch of hot slab slabs into the first heating furnace and the charging pitch of cold slab slabs into the second heating furnace may be made constant. However, in this case, if the supply amount of unheated slabs increases due to changes in the operating rate of the continuous casting machine, even if there is sufficient processing capacity in the rolling equipment or heating furnace, the high-temperature slabs immediately after casting will be transferred to cold slabs. This results in waste.

In addition, for example, when changing the slab charging pitch of the first and second heating furnaces due to changes in the operating rate of the continuous casting machine,
The rolling amount changes greatly depending on the change in the operating rate of the casting machine, and the large change in the operating rate of the rolling equipment hinders the increase in the target rolling amount. Furthermore, when the amount of heat treatment exceeds the processing capacity of the rolling equipment, the slab must be placed on standby in front of or inside the heating furnace, leading to a decrease in efficiency. However, in the present invention, the magnitude relationship between the amount of slabs fed out from the continuous casting machine and the receiving capacity of the first heating furnace,
Also, the pitch at which slabs are charged into the first heating furnace and the loading pitch at which slabs are loaded into the second heating furnace are determined depending on the magnitude relationship between the amount of heated slabs in the first and second heating furnaces and the rolling capacity of the rolling apparatus. This automatically adjusts the ratio between the slab charging pitch in the second heating furnace and the slab charging pitch in the first heating furnace depending on the situation. Even if the operating rate of the machine changes, it is possible to prevent empty spaces from forming in the first heating furnace. By changing the fuel supplied to the first and second heating furnaces in accordance with the slab charging pitch of each heating furnace, unnecessary fuel consumption can be avoided. For example, as the operating rate of the casting machine decreases, the slab charging pitch of the first heating furnace can be slowed down, and the slab charging pitch of the second heating furnace can be kept constant or fast, thereby reducing the load on the rolling equipment. It is possible to reduce the rate of decline in the slab supply amount and suppress the decline in the operating rate of the rolling mill. [Example] Figure 1 shows the layout of each component of a casting and rolling system that implements one embodiment of the present invention. Referring to Figure 1, this system includes three continuous casting machines CCI and CG2.
and CC3. Slabs produced by these casting machines ride on predetermined carts and approach the rolling facility HSM through freight lanes RL 1 - RL 2 - RL 3 provided as transport equipment in order. In this example, the slab conveyance route includes a first stage where the relatively high-temperature slab (i.e. hot slab) immediately after being produced is heated in the heating furnace HH to the temperature required for rolling, and then immediately sent to the rolling equipment HSM. There is a second route in which the slabs (i.e., cold slabs), which have passed through the slab storage yard YDI and are on standby and whose temperature has decreased somewhat, are heated in the heating furnace HL and sent to the rolling equipment HSM.

One heating furnace HH is assigned exclusively to hot flakes, and the other heating furnace HL is assigned exclusively to cold flakes. In other words, the heating time required for hot pieces and the time required for heating cold pieces are significantly different, and if both are mixed in one heating furnace, the furnace time must be determined to satisfy the conditions for cold pieces, which take a long time. To prevent this, the efficiency of the heating furnace deteriorates, so both are processed in separate heating furnaces. The transportation process includes selecting the destination of the slab arriving from the continuous casting machine (distribution into hot pieces and cold pieces), charging the slab to each heating furnace, and extracting the slab from each heating furnace. Automatically controlled by the control computer CPU. When a slab that has arrived from a continuous casting machine is heated and rolled as a hot piece, the slab is transferred onto a transfer table TBH by a crane CLH at the position of the hot piece yard VD2, transported by the table, and heated. It is charged into one end of the furnace HH and heated together with the other hot pieces that have been charged up to that point. After the time required for the slab to reach a predetermined temperature (for example, 1 minute) has elapsed since it was loaded, the slab is extracted from the other end of the heating furnace and conveyed to the rolling mill HSM by the extraction table TBO. When the slabs arriving from the continuous casting machine are treated as cold pieces, the slabs pass over the freight lane RL3 and are transferred to the slab storage yard YD.
Transported to I. The slabs ordered in this slab storage area,
That is, cold pieces are used as needed. That is, the cold pieces are transferred by the crane CLL to the material transfer table TBL, transported on the table, charged into one end of the heating furnace HL, and heated together with the other cold pieces charged so far. After the time required for the slab to reach a predetermined temperature (for example, 4 minutes) has elapsed after being charged, the slab is extracted from the other end of the heating furnace and transported to the rolling mill HSM by the extraction table TBO. By the way, the amount of slabs produced and the rolling speed are not constant. If a space is created in the heating furnace HH due to these changes (the throughput is less than the processing capacity), the energy efficiency of the heating furnace will decrease.In order to prevent this and increase efficiency, the transfer control computer CPU Depending on the situation, the ratio of charging pitch of hot slabs to heating furnace HH and charging pitch of cold slabs to heating furnace HL is automatically adjusted, and the charging pattern of slabs to heating furnaces HH and HL is adjusted. change. Among the slabs arriving from the continuous casting machine, the extra slabs that are not charged into the heating furnace HH are transported to the slab yard MDI as cold pieces. For example, in rolling equipment, it is necessary to change the rolling speed to adjust the finish rolling temperature, and if the product size changes, the required rolling time will change even if the rolling speed is constant. :tun/time) changes. In addition, in a heating furnace, the time the slab is in the furnace (the time it is in the heating furnace) and the temperature during extraction must be above a specified level, and this is determined by the material of the slab. The processing amount (T/H) or charging/extraction amount in the heating furnace needs to be adjusted to the one that takes the longest time among the group of slabs in the heating furnace that are being processed at that time. In addition, it is not possible to keep the slab heated to the rolling temperature for a long time before the rolling equipment (
(The temperature decreases), so the throughput in the heating furnaces HH and HL cannot exceed the throughput of the rolling equipment. Furthermore, depending on the casting schedule or for equipment maintenance, some of the multiple casting machines may be suspended or the operating rate of each casting machine may be changed, so the slabs produced may be ffi (T/H) changes. For example, when keeping the slab charging pitch of the heating furnace HH constant, if the slab arrival pitch is delayed due to suspension of some casting machines, etc., there will be no slabs to be charged at the scheduled charging timing. It is necessary to create an empty area in the furnace HH, the heat processing amount (T/H) becomes smaller than the processing capacity of the HH, and the energy usage efficiency decreases. In order to eliminate such inconveniences, the conveyance control computer CPU performs control as shown in FIG. This will be explained with reference to Figure 2. In step 1, data on the casting process and rolling process is obtained. That is, the conveyance control computer CPU controls the continuous casting machines CCI and CC2.
, CC3 process control computer (not shown) and the rolling equipment HSM process control computer (not shown) are connected, so it communicates with them and reports the operating status of each casting machine and slab slab. Input the material, etc. as casting process data, and the rolling speed, etc. as rolling process data. In step 2, various parameters are determined by calculation. First of all,
Calculate the amount (T/H) of slabs (hot slabs + cold slabs) that come out of the continuous casting machine and arrive at the hot slab yard YD2. It can be determined by calculation based on the required time.Next, the throughput (T/H) of each heating furnace HH and HL at that time is determined.
This can be determined, for example, as the average value of the slab charging pitch and slab extraction pitch of each heating furnace. Next, find the maximum rolling capacity RVM of the rolling equipment at that time.
This can be calculated based on the conveyance speed of the finish rolling section at that time, the size of the slab, and the material. In step 3, the maximum throughput (processing capacity) of the heating furnace HH is compared with the slab charging pitch to ensure that the latter does not exceed the former. The slab charging pitch can be determined as KXVTA. For example, when the distribution ratio K is 0.8, 80% of the slabs arriving from the continuous casting machine are charged as hot pieces to the heating furnace HH, and the remaining 20% are transferred as cold pieces to the slab storage YDI. will be transported to. In step 4, the processing jiHTH in the heating furnace HH is compared with the amount of heat flakes arriving VTA. If HTH>VTA, proceed to step 8. If HTH≦VTA in step 4, proceed to step 5.
Rolling capacity RVM of rolling equipment and amount of slab during heat treatment HT
Compare with T. The slab amount HTT is HTH+HTL. If RVM≦HTT, the amount of slab during heat treatment is excessive compared to the amount that can be rolled, so it is necessary to reduce it. In that case, proceed to step 8.

In step 8, the slab charging pitch Phi of the heating furnace HH is
Reduce the value of (T/H). The slab charging pitch of the heating furnace HL will not be changed. As a result, heating furnaces HH and HL
The ratio of the slab charging pitch to the slab charging pitch is changed. In other words, when proceeding from step 4 to step 8, the charging pitch Phi is reduced to adapt to the decrease in the running capacity of the casting machine, and when proceeding from step 5 to step 8, it is adjusted to the rolling capacity of the rolling equipment. As such, the charging pitch Phi decreases. Note that if the charging pitch Phi decreases, the heating capacity of the heating furnace HH may be lowered.
Reduce the amount of fuel used. If RVM>HTT in step 5, execute the next step 6 and change HTT to the rolling target value S P V (T/
Compare with H). If it is HTTksPV, proceed to step 7. In step 7, the slab charging pitch Phi of the heating furnace HH is
Increase the value of (T/H). The slab charging pitch of the heating furnace HL will not be changed. As a result, heating furnaces HH and HL
The ratio of slab charging pitch with In other words, the amount of hot flakes arriving VTA is larger than the current processing amount of the heating furnace HH (the charging pitch of HH can be increased), the rolling capacity RVM has a margin compared to the heating processing amount HTT, and the heating processing amount HTT is less than the target amount of rolling SPv, the value of the slab charging pitch Phi is increased. In addition,
When the charging pitch Phi increases, it is necessary to increase the heating capacity of the heating furnace HH, so in this case, the fuel supplied to the heating furnace HH is increased. As a result, the charging pitch of the heating furnace HH increases and
The amount of H processed increases, the extraction pitch increases, and the amount of rolling increases. The charging pitch and extraction pitch are adjusted so that no empty space is left in the heating furnace. That is, when the empty space is likely to increase, the charging pitch is made larger than the extraction pitch and adjusted in the direction of decreasing the empty space, and when the empty space approaches zero, the charging pitch and the extraction pitch are made equal to <sh, Maintain that state. When the amount of arriving slabs decreases due to suspension of the casting machine, etc., the processing capacity of the heating furnace HH is reduced and the slab stays in the furnace longer, so the charging pitch and extraction pitch (T/H) are reduced (in terms of time). This prevents empty spaces from forming in the heating furnace HH due to late arrival of slabs. On the other hand, when the amount of arriving slabs increases due to an increase in the operating rate of the casting machine, etc., use the heating furnace HH as much as possible.
Increase the processing capacity of the furnace, shorten the furnace time of the slab, increase the charging pitch and extraction pitch (T/II) (shorter in terms of time), and prevent the slab from stagnation in front of the heating furnace. . When the charging pitch reaches the upper limit, the distribution ratio K is reduced and a portion of the slabs arriving from the casting machine are sent to the slab storage MDI. If the charging pitch Phi is adjusted in step 7 or 8, step 9 is executed. In this step,
Hot piece charging pitch Phi for heating furnace HH and heating furnace HL
The charging pattern of hot pieces and cold pieces is reset according to the ratio R}IL of the cold piece charging pitch Pli to the cold piece charging pitch Pli. For example, assuming that the slabs are all the same size and material, the ratio RHL is 2:1 (Phi, Ph
In case i), the order in which the slabs are charged is HH, HH.
HL,I{H. HH. When the ratio R}IL is 3/2:1, the order in which the slabs are charged is HH, HH, HL, HH, HL, HH, HH.
, HL, HH, HL. HH. Let HH,... Of course, the slabs charged into the heating furnace HH are hot pieces, and the slabs charged into the heating furnace HL are cold pieces extracted from the slab storage YDI. In Step IO, according to the charging pattern set in Step 9, slabs are charged to the heating furnaces HH and HL.
Control extraction. Also, depending on K, the distribution of arriving slabs into hot and cold pieces is controlled. Figure 3 shows an example of changes in the throughput in the heating furnace in response to changes in the operating rates of the continuous casting machines CCI, CC2, and CC3.
In this example, all slab specifications were assumed to be the same, and the following cases were assumed. Thickness: 240 mm Width: 1,200 mm Length: 10,000 mm Weight: 22 tons For convenience of explanation, all slabs have the same specifications in this example, but in reality, slabs with the same specifications are rarely rolled continuously. Rare. Furthermore, when the charging pitch of the heating furnaces HH and HL was at its maximum, the in-furnace time per slab was approximately 1 minute and approximately 4 minutes, respectively. The various numerical values for each operation pattern in the example shown in Figure 3 are shown in Table 1 below. Referring to Table 1, Figure 3, in this example, the production volume of slabs fluctuates greatly due to changes in the operating rate of each continuous casting machine and suspension of some casting machines. However, Figures 3 and 1
As shown in patterns 1.2 and 3 in the table, the slab charging pitch of the heating furnace HL is kept constant, and the variation is absorbed by adjusting the slab charging pitch of the heating furnace HH. In other words, when the amount of slabs arriving at the heating furnace HH increases, the heating capacity is increased and the charging pitch (time /
When the amount of slabs arriving at the heating furnace HH decreases, the charging pitch is lengthened to reduce the heating capacity (reduce the amount of fuel supplied). As described above, the pattern of the order in which slabs are charged into the heating furnaces HH and HL is automatically changed in accordance with a change in the charging pitch of the heating furnace HH, that is, a change in Rl. This prevents empty spaces from forming in the heating furnace HH and prevents excess fuel from being consumed in the heating furnace HH. In this example, the charging pitch of the heating furnace HL is constant, but this needs to be changed as the material and size of the slab changes. Furthermore, for example, the charging pitch for the heating furnace HL may be changed in conjunction with the change in the charging pitch for the heating furnace HH. [Effect] As described above, according to the present invention, the conveyance control means (CPU)
The magnitude relationship between the amount of slabs fed out from the continuous casting machine (VTA) and the receiving capacity of the first heating furnace (H H), and the heating slabs of the first heating furnace and the second heating furnace (H L) Volume (HTT) and rolling capacity of rolling equipment (RVM)
The ratio of the pitch at which slabs are charged into the first heating furnace and the pitch at which slabs are charged into the second heating furnace is automatically adjusted according to the size relationship between the slab amount (VTA). It is possible to prevent the occurrence of empty space in the first heating furnace due to fluctuations, and it is possible to avoid a decrease in efficiency in the heating furnace (HH).

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing the layout of each component of a type of casting and rolling system implementing the present invention. FIG. 2 is a flowchart showing an outline of the operation of the CPU shown in FIG. Figure 3 is a time chart showing an example of changes in processing amount. CCI-CC3: Continuous casting machine RLI to RL3: Cargo lane HSM: Rolling equipment YDI: Slab yard YD2: Hot piece yard HH: Heating furnace HL: Heating furnace TBO:
Extraction table CLL, CLH: Crane 18
one

Claims (1)

[Claims] A plurality of continuous casting machines: A cold piece storage area: A first heating furnace that heats the comparatively high-temperature slab to a predetermined rolling temperature: A comparatively low-temperature slab exiting from the cold piece storage area A second heating furnace that heats the slab to a predetermined rolling temperature: transports the slab obtained by the continuous casting machine and carries the slab into the first heating furnace, or transports the slab into the first heating furnace via the cold piece storage area. a conveyance mechanism that transports the slabs into the second heating furnace; a rolling device that sequentially receives and rolls the slabs coming out of the first heating furnace and the second heating furnace; and a rolling device that controls the conveyance mechanism and The magnitude relationship between the amount of slabs fed out from a plurality of continuous casting machines and the receiving capacity of the first heating furnace, and the magnitude relationship between the amount of heated slabs of the first and second heating furnaces and the rolling capacity of the rolling device. Conveyance control means for automatically adjusting the ratio of the pitch at which the slabs are charged into the first heating furnace and the pitch at which the slabs are charged into the second heating furnace according to the relationship. Device.