JP3061362B2 - Heating furnace extraction control method for hot rolling line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the extraction of a heating furnace in a hot rolling line, and more particularly, to a DHCR (Direct Hot Cham) for synchronizing continuous casting and hot rolling.
rge Rolling) It is possible to adjust the extraction order and pitch when extracting slabs from a heating furnace without causing a mismatch in DHCR synchronized operation, which is suitable for use in a hot rolling mill including a heating furnace. Also, the present invention relates to a heating furnace extraction control method for a hot rolling line.

[0002]

2. Description of the Related Art In recent years, in order to improve rolling efficiency and reduce costs, so-called DHCR operations, in which continuous casting and hot rolling are operated in synchronization with each other, have been carried out at hot rolling mills for hot slip, thick plates, section steel, and the like. Is becoming increasingly common. In this DHCR operation, the tapping capacity based on the casting speed (ton / hour) and the rolling efficiency based on the heating / rolling capacity are calculated in advance (called time calculation), and scheduling is performed. And then synchronize.

That is, in a continuous heating furnace of a pusher type or a walking beam type, the slab extraction capacity and the charging capacity are almost equal to each other, or the charging capacity is slightly higher.
However, when charging is instantaneously delayed, it is necessary to predict and detect this and lower the extraction pitch of the heating furnace. Conversely, when charging is fast, it is necessary to increase the extraction pitch. This adjustment is essential, especially in DHCR operations that are synchronized with continuous casting.

[0004]

Conventionally, however, a number of methods for controlling the extraction pitch have been proposed, but no method for determining or changing the extraction order online has been proposed. That is, conventionally, only the extraction order determined in advance in consideration of the continuity of the rolling dimensions and the heating temperature is followed, and the extraction order change due to the operation fluctuation is all performed manually by the operator, or the efficiency decreases, but the pitch decreases. I went down and waited for the environment to recover.

[0005] Therefore, when tapping, stoppage of rolling, pitch down, time calculation error of continuous casting / rolling, or instantaneous mismatching due to troubles or the like, or instantaneous mismatching occurs, the adjustment cannot be performed sufficiently and the synchronization operation is broken. There was a problem that.

[0006] For example, when the tapping (loading) capacity is higher than the rolling (extraction) capacity, the slab stagnates on the heating furnace charging side, causing a decrease in temperature and a deterioration in fuel cost. On the other hand, when the tapping (charging) capacity is lower than the rolling (extraction) capacity, the slab is insufficient on the charging side of the heating furnace, and if the extraction is continued, an empty furnace is generated and the fuel cost deteriorates. In addition, the extraction is stopped, and downtime waiting for the arrival of the slab occurs, or the rolling mill is pitched down, and the rolling efficiency is reduced.

[0007] On the other hand, as having some relevance to the present invention, Japanese Patent Application Laid-Open No. 4-143222 discloses a heating rate for baking from the current billet temperature to the target outlet temperature.
The time required for the billet to reach the belt exit from the current loading position, the ratio of the decarburizing agent to the total number of cargoes in each belt, and the contribution rate (weight) of each billet are defined as fuzzy variables. It states that each of the four variables is ruled in accordance with the manner of change, but only determines the set furnace temperature and is not used to determine the extraction order or extraction pitch. .

The present invention has been made to solve the above-mentioned conventional problems, and provides a method for controlling the extraction of a heating furnace in a hot rolling line, which can reliably prevent a mismatch in DHCR synchronization operation. The purpose is to:

[0009]

SUMMARY OF THE INVENTION The present invention relates to a hot rolling line including a DHCR-executing heating furnace for operating a continuous casting and a hot rolling in synchronization with each other. This problem has been solved by predicting and calculating the empty furnace distance of the DHCR, and adjusting at least the extraction order and the extraction pitch of the DHCR-executing heating furnace according to the prediction calculation result.

In addition, the charging-side empty furnace distance at a predetermined time in the future is calculated from the charging-side empty furnace distance at the present time to the total width of slabs to be charged from the current time to the predetermined time (including the slab interval). ) Is subtracted and the sum of the widths of the slabs (including the slab intervals) extracted from the current time to the predetermined time is also calculated.

When the extraction adjustment of a certain heating furnace and the extraction adjustment of another heating furnace are contradictory, the frequency of each action is determined by a non-linear function, and adjustment is made based on the magnitude relation. .

Further, the distance of the nearest air furnace and the distance of the future air furnace are both predicted and calculated. In accordance with the distance of the future air furnace, the furnace is moved greatly in units of band immediately after charging the heating furnace, and the distance to the nearest air furnace is determined. Accordingly, adjustment is made immediately before the extraction.

In the present invention, the distance of the empty furnace on the inlet side of the heating furnace interior (when the value is negative, the charging side has a dub) is predicted and calculated. Since the pitch (pitch up / pitch down / pitch down) and the extraction pitch (pitch up / pitch down / pitch down) are adjusted in advance, it is possible to reliably prevent a mismatch in the DHCR synchronization operation.

As shown in FIG. 1, a slab 8 cast by a continuous casting machine 10 is conveyed to a slab yard 14 by a directly connected carriage 12, and is pushed from conveyors 16 and 18 provided in the slab yard 14 by pushers (shown in FIG. 1). For example, four heating furnaces 21, 22, 23, 2
4, and the slab 8 heated by the heating furnaces 21, 22, 23, 24 is extracted to the rolling line 28 from the opposite side.

According to the present invention, as shown in FIG. 2, the air furnace distance on the inlet side inside the heating furnace at a certain point in the future is predicted. Specifically, first, the charging-side empty furnace distance Yf after x minutes from the present is predicted by the following equation.

Yf = Yp−Sin + Sout (1)

Here, Sin is the total width of the slab to be charged in the next x minutes (the sum of the slab width Wy and the slab interval Py in FIG. 2), and is the result of continuous casting, the tapping speed, and the direct connection bogie. 12 and the like. Also, Sout is
From this, the sum of the slab widths extracted in x minutes (similarly, the sum of the slab width Wy and the slab interval Py) can be calculated from the in-furnace time prediction used in the combustion control of the heating furnace.

When the charging-side empty furnace distance Yf x minutes after the present can be predicted by the equation (1), the extraction pitch of each furnace is increased according to a nonlinear function as shown in FIG. ), And instruct pitch down as it is. This can, for example, give instructions to the operator or automatically give an automatic extraction function. Here, when the pitch adjustment of a certain heating furnace and the pitch adjustment of another heating furnace are contradictory (when a certain heating furnace is pitched up, another heating furnace is relatively pitched down), each action is performed. (The vertical axis in FIG. 3) is determined based on the magnitude relationship, and, for example, the one with the higher frequency can be prioritized.

In particular, the distance of the nearest air furnace and the distance of the future air furnace are both predicted and calculated. Accordingly, when the adjustment is performed immediately before the extraction, more accurate adjustment can be performed.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 4, the apparatus for carrying out the present invention includes a scheduled charging time calculating section 30, a scheduled extracting time calculating section 32, an empty furnace distance estimating section 34, and a stop / go determining section 36. It is composed of

The estimated charging time calculating unit 30 has dozens of uncharged materials of each furnace as a table (referred to as a charging order table) (No. 1 to No. 3 heating furnaces 21, 22, and 23). For example, the estimated charging time for each slab is calculated for each slab, for example, about 15 pieces each, and the No. 4 heating furnace 24, which is a DHCR operation heating furnace, for example, about 40 pieces.

The items in the charging order table for each furnace include, for example, cycle number + extraction order, standard, tracking position, charging route, chargeable furnace (furnace charged in each furnace-specific cycle), and charging. An entry number (temporary) (equally allocated to each of the furnaces that can be charged), a slab length, a slab width, a slab weight, an estimated charging time, an experiment number, and the like.

The estimated charging time Tin is estimated with respect to the DHCR material based on the on-line standard estimated heating furnace arrival time Tar as shown in the following equation, and corrected based on the results such as casting start and torch cutting.

Tin = Tar + (the latest result−prediction) (2)

On the other hand, for the materials other than the DHCR material, only the materials on the conveyors 16 and 18 are targeted, and for the other yard materials, there is no loading delay, and the estimation is made by the following equation.

Tin = Tp + Tcv + Tlift + Ttable (3)

Here, Tp is the current time, Tcv is the conveyor transfer time (a function of the position and the number of sheets), Tlift is the lifter time (a constant in a pattern), and Ttable is the table transfer time (a function of the route and the heating furnace number). .

The scheduled extraction time calculation unit 32 includes all the slabs existing in the soaking zone in the latter half of the heating furnace,
Calculate the extraction pitch on the rolling line 28 side and the heating furnace extraction pitch from the viewpoint of the degree of burning of the heating furnace for one of the pieces to be entered (a margin), and set the later value of both as the scheduled extraction time. .

The air furnace distance estimating section 34 calculates the nearest air furnace distance Ynf at the time of starting the extraction of the key slab (for example, a second slab to be taken out) at the time of calculation by the following equation.

Ynf = Yp + Z1-Fl (5)

Here, as shown in FIG. 5, Yp is the current distance of the empty furnace on the charging side, and Z1 is the distance from the furnace port to the head of the key slab, and uses the in-furnace tracking result. Also, Fl
Is the charging furnace length up to the extraction of the key slab, and is the total sum of the widths of the slabs (see the charging order table) to be charged into the furnace from the present to the scheduled start time of the key slab extraction.
In the case of reactors 2 to 4, the slab spacing (for example, 70
mm) x number of sheets.

Further, with respect to the DHCR operating furnace, the future empty furnace distance Yff at the time of completion of the isotropy extraction is calculated using the following equation.

Yff = Yp + Z2-F2 (6)

Here, as shown in FIG. 6, Z2 is the distance from the furnace port to the head of the second heating zone head slab, and F2 is the charging furnace length until the second heating zone head slab is extracted. In addition,
The calculation method of the distance Z2 and the furnace length F2 is as follows:
This is the same as in the case of F1.

The stop / go determination unit 36 uses the future furnace distance Yff calculated by the furnace distance estimating unit 34 to perform a “future replacement” operation in which the furnace is largely moved immediately after charging of the heating furnace in band units. Using the empty furnace distance Ynf, “nearest replacement” is performed to adjust immediately before extraction (about 10 to 30 minutes).

More specifically, in the latest replacement, as shown in FIG. 7, the frequency of the action is determined by a three-stage nonlinear function of advancing (U) / as is (S) / decreasing (D) in the order of extraction. . FIG. 7 (A) shows the first reactor, FIG. 7 (B) shows the second reactor,
Reactor No. 3 and FIG. 7 (C) shows the nonlinear function of Reactor No. 4. Here, as for the No. 4 reactor, a lift-up charger is provided, and a considerable empty furnace is also permitted. Therefore, if "as is", the empty furnace distance is long.

On the other hand, in future replacement in which the future is viewed for about 30 minutes to one hour from the present time, as shown in FIG. 8, (STAY), pitch up (PU) / pitch down (D), large pitch up (PU) ² ) The frequency of action is determined by a five-step nonlinear function of large pitch down (PD ² ). Fig. 8 (A) is the first reactor, Fig. 8 (B) is the second reactor,
FIG. 8C shows a No. 3 furnace, and FIG.

In this way, by performing the up / down or pitch up / pitch down of the extraction order using both the latest and future charging side air furnace distances Ynf and Yff as parameters, accurate extraction without mismatch is performed. be able to.

Note that examples of the non-linear function for performing the latest replacement and the future replacement are not limited to FIGS. Further, only one of the latest replacement and the future replacement may be used.

[0041]

According to the present invention, the distance of the empty furnace on the charging side is used as a parameter, so that the order of extraction from the heating furnace and the extraction pitch can be accurately controlled, and the mismatch can be prevented even in the DHCR operation. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration example of a hot rolling mill to which the present invention is applied.

FIG. 2 is a plan view showing the situation inside the heating furnace.

FIG. 3 is a diagram illustrating an example of a non-linear function for determining an action frequency used in the present invention.

FIG. 4 is a block diagram showing an overall configuration in an embodiment of the present invention.

FIG. 5 is a plan view for explaining the principle of calculating the latest air furnace distance in the embodiment of the present invention.

FIG. 6 is a plan view for explaining the principle of calculating the future furnace distance in the same manner.

FIG. 7 is a diagram showing an example of a non-linear function for immediate replacement used in the stop / go determination unit of the embodiment of the present invention.

FIG. 8 is a diagram showing an example of a non-linear function for future replacement as well.

[Explanation of symbols]

 8 ... Slab 10 ... Continuous casting machine 12 ... Directly connected carriage 14 ... Slab yard 16,18 ... Conveyor 21,22,23,24 ... Heating furnace 28 ... Rolling line 30 ... Scheduled charging time calculation unit 32 ... Scheduled extraction time calculation unit 34: empty furnace distance estimating unit Ynf: nearest empty furnace distance Yff: future empty furnace distance 36: stop / go determination unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-330152 (JP, A) JP-A-5-59438 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 37/00 C21D 9/00

Claims (4)

(57) [Claims] 1. A hot rolling line including a DHCR heating furnace for operating a continuous casting and a hot rolling in synchronization with each other, and predicts and calculates an empty furnace distance on a heating furnace interior entrance side at a predetermined time in the future. According to the prediction calculation result, at least the extraction order and the extraction pitch of the DHCR-executing heating furnace are adjusted in advance to prevent a mismatch of the DHCR synchronization operation, thereby extracting the heating furnace from the hot rolling line. Control method. 2. The method according to claim 1, wherein the charging-side empty furnace distance at a predetermined time in the future is calculated from a charging-side empty furnace distance at a current time to a total width of slabs to be charged from the current time to the predetermined time. Hot rolling characterized by subtracting the slab spacing (including the slab spacing) and adding the sum of slab widths (including the slab spacing) also extracted from the current time to the predetermined time. Line heating furnace extraction control method. 3. The method according to claim 1, wherein when the extraction adjustment of a certain heating furnace and the extraction adjustment of another heating furnace are contradictory, the frequency of each action is determined by a non-linear function, and the adjustment is performed based on the magnitude relation. A heating furnace extraction control method for a hot rolling line. 4. The method according to claim 1, further comprising predicting and calculating both the latest air furnace distance and the future air furnace distance, and moving the air furnace greatly in band units immediately after charging the heating furnace according to the future air furnace distance.
A method for controlling the extraction of a heating furnace in a hot rolling line, wherein the adjustment is performed immediately before the extraction in accordance with the latest air furnace distance.