JPH05154528A - Method for controlling temperature at inlet side in hot-continuous finish-rolling mill - Google Patents

Abstract

PURPOSE:To improve the productivity by approaching a waiting time based on temp. regulation at the inlet side of a finish rolling mill to a waiting time based on the regulation of a mill pacing control as nearer as possible. CONSTITUTION:At the inlet side of the finish rolling mill F, plural pieces of descaling headers 21-24 are arranged and also, the temp. of a material S to be rolled is measured with a thermometer 10 at this inlet side and combination of the descaling header obtaining the necessary cooling capacity for approaching the FET waiting time to the MPC waiting time from this measured temp. and the FET is selected. By using the selected descaling header, the material to be rolled is passed while spouting high pressure water.

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 temperature of a material to be rolled when hot-rolling a strip steel, and more particularly to maintaining the temperature of the material to be rolled supplied to a finish rolling mill at a predetermined target temperature. However, the present invention relates to a temperature control method capable of shortening the waiting time on the entry side of the finish rolling mill as much as possible.

[0002]

2. Description of the Related Art A material to be rolled supplied to a hot continuous finishing mill (hereinafter simply referred to as a finishing mill) does not collide with the tail end of a preceding rolling material, so that the finishing rolling is based on the regulation of so-called mill pacing control. Machine waiting time (MPC waiting time) and waiting time based on regulation of finish rolling machine target temperature that is set in order to obtain the required material and suppress the generation of secondary scale (FET waiting time) ) And, it is necessary to wait on the delay table on the entry side of the finishing mill for the longer time, whichever is longer.

Conventionally, as shown in, for example, Japanese Patent Laid-Open No. 62-289308, the FET waiting time is treated as one condition of MPC, and the FET waiting time is not particularly controlled.

[0004]

The above-mentioned MPC waiting time is inevitably determined by the pass schedule of the material to be rolled which is successively rolled by the finish rolling mill, the mill ability, etc., and this is unavoidable. However, although the FET standby time can be shortened as long as the target temperature can be obtained, it is waiting for the material to be rolled to cool on the delay table by cooling and to reach the target temperature. It was

In the case of normal rolling, the FET waiting time is often longer than the MPC waiting time because rolling is performed on the high temperature side in the rough rolling machine in order to secure the FET. Therefore, in the finish rolling mill, the rolling pitch is influenced by the FET waiting time, which hinders the productivity. In particular, the tip of the rolled material is hotter than the center because it is affected by the radiant heat from the furnace wall in the heating furnace, and the lock-on plate thickness and lock-on load for automatic plate thickness control are accurately measured. In order to obtain the same and to prevent the tip from plunging into the space between the table rollers, it is necessary to properly manage the FET.

The present invention solves the above-mentioned problems in the prior art by utilizing a scale breaker on the entry side of the finishing rolling mill.
An object of the present invention is to provide a method for controlling the inlet side temperature of a finish rolling mill that can prevent productivity from being hindered as much as possible by approaching the C standby time.

[0007]

The present invention is a method for controlling the inlet side temperature of a hot continuous finishing mill, wherein a plurality of high pressure water jet descaling headers can be selectively used on the inlet side of the finishing mill. In addition, the temperature of the material to be rolled is measured on the further inlet side of this descaling header, and the finishing-roller inlet-side standby time based on the temperature regulation is milled based on this measured temperature and the finishing-roller inlet-side target temperature. Select a combination of the descaling headers that provides the cooling capacity required to approach the waiting time of the finishing mill entry side based on the control regulations, and perform rolling while injecting high-pressure water using the selected descaling headers. By passing the material through the plate, the above-mentioned problems of the conventional technology are overcome, and further, the measured temperature is the temperature of the tip of the material to be rolled and the combination of the descaling header is selected. While jetting high-pressure water and,
At the leading edge of the material to be rolled, the waiting time of the material to be rolled and supplied to the finishing mill by adjusting the conveying speed and passing it can be made closer to the waiting time based on the regulation of mill pacing control. is there.

[0008]

[Function] A plurality of descaling headers installed on the entry side of the finishing rolling mill can be selectively used by combining one set up and down or by combining a plurality of descaling headers. Depending on the choice, the required cooling can be carried out. Then, the temperature of the material to be rolled is measured further on the entry side of the descaling header. This temperature measuring position is preferably at the tip of the material to be rolled. This is because, as mentioned above, the temperature of the tip is high, the lock-on plate thickness and lock-on load for automatic plate thickness control can be accurately obtained, and the tip is prevented from plunging between the table rollers. by.

From the temperature thus measured, a predetermined FET can be obtained by taking into consideration the subsequent cooling during the transportation of the material to be rolled and the cooling by normal descaling.
Find the waiting time. Then, a combination of descaling headers is selected that has a cooling capacity that allows the FET standby time to be as close as possible to the MPC standby time. In this case, instead of the FET waiting time, the temperature on the entry side of the finishing rolling mill is estimated from the measured temperature and the MPC waiting time of the material to be rolled, and the descaling header is calculated from the cooling capacity required to bring the estimated temperature closer to the FET. The same is true even if a combination of is selected. By using the descaling header selected in this way to pass the material to be rolled while injecting high-pressure water, the FET standby time is reduced as much as possible.
It becomes possible to approach the C waiting time.

For finer temperature control, after selecting the combination of descaling headers as described above, the tip of the material to be rolled passes through the position of the descaling header in order to adjust the cooling during descaling. Adjust the transport speed of the roller table. For example, when the combination of the selected descaling headers causes a slight overcooling, the conveyance speed of the roller table is increased, and when the cooling is insufficient, the MPC is passed through the jetted high-pressure water to slow down the MPC. An accurate FET can be obtained with a waiting time that is almost equal to or slightly longer than the waiting time.

Since the FET is not required so accurately except for the tip of the material to be rolled, it can be represented by the temperature measured only at the tip, or if necessary, the temperature is sampled to measure the descaling header. It is also possible to change the combination of use, and since it is easy to cool the water other than the tip part for riding water, the injection of high pressure water from the upper and lower descaling headers of 1 to 2 sets automatically stops after passing the tip part. It may be allowed to. However, the transport speed depends of course on the rolling speed because the tip of the material to be rolled has already been caught in the finishing mill.

Here, the temperature measurement position of the tip is not particularly strict at a position of about 1 to 2 m from the tip of the material to be rolled, and the length of the tip is the length when it exits the finishing rolling mill. The length is equivalent to about 40 to 100 m when converted.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an arrangement example of equipment on the entrance side of a finishing rolling mill for carrying out the present invention, FIG. 2 shows an example of selecting a descaling header, and FIG. An example of adding speed adjustment is shown. In FIG. 1, F
Is a finish rolling mill, F ₁ is the first stand, F ₂ is the second stand, and the stands of the subsequent stages are not shown.
FS is a flying shear, which cuts and removes the crop at the tip of the rolled material S. In this example, four sets of upper and lower descaling headers 21 to 24 are installed on the inlet side of the finishing rolling mill F as the finishing inlet scale breaker FSB, and the shutoff valves 41 to 44 are provided on the respective pipelines 31 to 34. The four descaling headers 21 to 24 are installed so that one set or a combination of a plurality of sets can be selectively used. Reference numeral 10 denotes a radiation thermometer provided further on the entrance side of the descaling headers 21 to 24. Next, the temperature of the material to be rolled S ₂ supplied to the finishing rolling mill F is measured, and the temperature measurement result is sent to the arithmetic unit 11. To transmit. In the arithmetic unit 11, the MPC waiting time TM obtained from the rolling schedule by this arithmetic unit or a higher-level arithmetic unit and the FET are stored, while the cooling capacity SB by each combination of the descaling headers is as follows, for example. Has been entered in. Therefore, the cooling capacity at that time can be easily calculated from the plate thickness, temperature, plate passing speed, etc. of the material to be rolled.

(1) When only SB ₁ = 24 is used (2) When SB ₂ = 24 and 22 is used (3) When SB ₃ = 24 and 23 is used (4) SB ₄ = 24 And when using 22 and 23 (5) SB ₅ = when using all descaling headers Then, in the computer 11, the measured temperature of the thermometer 10 and the descaling headers normally used from the FET (in this example, (( 1))
Is used to find the FET waiting time T in the case of conveyance while performing descaling, and the combination of the descaling headers is selected so that this T is as close as possible to the MPC waiting time for not colliding with the preceding rolled material S _1. To do.
An example of this case is shown in FIG. In FIG. 2, as described above, the cooling capacity when only the descaling header 24 is used (1) is SB ₁ , and the FET standby time in this case is T 1.
_{It is 1} , which is longer than the MPC waiting time TM by Td. Therefore, the computing unit 11 selects the combination (3), which is the cooling capacity SB ₃ that is longer than TM and provides the closest standby time, from the combinations of descaling headers. That is, the waiting time becomes T ₃ , and the time saving of Td ′ can be achieved. In the above description, the FET waiting time T ₁ is obtained and brought close to TM. However, the temperature of the material to be rolled when waiting for a predetermined TM is estimated, and this temperature is the FET. As described above, the same result can be obtained by selecting a combination of descaling headers as described above.

Next, in the case of finely controlling the temperature
An example will be described with reference to FIG. SB in the case shown in FIG.₃
The combination (3) that is
Material S ₂The transport speed of the
The cooling capacity when passing the positions of the headers 21 to 24 is SB
₃’ Therefore, the waiting time T₃Is T₃′
It is possible to save Ta time more than in the case of Fig. 2 and
As a result, it has become possible to shorten the Td ″ time.

Although it is conceivable to install a flow rate adjusting valve in the high pressure water pipes 31 to 34, it is not preferable because of a maintenance problem. The inlet side temperature control method of the finish rolling mill according to the present invention shown in FIG. 3 was carried out in a hot continuous finishing mill having an average coil weight of 20 t.
We were able to reduce the waiting time based on ET regulations from 23.7 hours / month to 16.4 hours / month by about 30%.

[0017]

By implementing the present invention, the waiting time of the material to be rolled on the entry side of the finish rolling mill can be significantly reduced, so that not only the productivity is improved but also the operating rate is improved. The economic effect will be enormous.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of arrangement of equipment on the entrance side of a finish rolling mill for carrying out the present invention.

FIG. 2 is an explanatory diagram showing an example of selecting a descaling header according to the present invention.

FIG. 3 is an explanatory diagram in the case where a conveyance speed adjustment of a rolled material tip portion is further added to the example of FIG. 2.

[Explanation of symbols]

 10 Thermometer 11 Computer 21-24 Descaling Header 31-34 Pipeline 41-44 Shutoff valve F Finishing mill S Rolled material

Claims (2)

[Claims] 1. A method for controlling an inlet side temperature of a hot continuous finishing mill, wherein a plurality of high-pressure water jet descaling headers are selectively installed on the inlet side of the finishing mill and the descaling is performed. The temperature of the material to be rolled is measured on the inlet side of the header, and the waiting time on the finishing mill entrance side based on temperature regulation is calculated from this measured temperature and the target temperature on the finishing mill entrance side to the finishing mill entrance side based on mill pacing control. It is characterized in that a combination of the descaling headers that provides a cooling capacity necessary for approaching the waiting time is selected, and the material to be rolled is passed through while jetting high-pressure water using the selected descaling header. Entry-side temperature control method for hot continuous finishing mill. 2. The measured temperature is the temperature of the tip of the material to be rolled, and a combination of descaling headers is selected to inject high-pressure water, and at the tip of the material to be rolled, the conveying speed is adjusted. A method for controlling the inlet side temperature of a hot continuous finish rolling mill, which is characterized by passing through a strip.