JPH04284913A - Method for controlling water cooling of wire rod - Google Patents

Abstract

PURPOSE:To provide a water cooling control means to reduce a cutoff amount of a tip of a wire rod. CONSTITUTION:A water cooling area 11 in a rolling process of the wire rod is divided into plural zones and cooling water supply tubes 14 to supply cooling water are connected independently to each zone. A timing to open a flow regulating valve at each zone and a necessary amount of cooling water in a water cooling area 11 are obtained by a cooling water arithmetic control unit 12 from indication values of thermometers 15, 16, water cooling indication values of the front end and the entire length of water cooling area, etc., installed on the inlet and the outlet sides of this water cooling area. Then, an amount of cooling water of each zone is obtained by a percentage distribution device 13 to control the flow regulating valve of each zone. An amount of cooling water supplied until the material in the water cooling area directly after the end of preceding water cooling area passes through this water cooling area can be controlled nearly to constant. The temperature of the material after it is cooled by water hardly gets drastically out of a target temperature. The yield of the wire rod can be improved.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a water cooling control method in the rolling process of wire rods (including steel bars), and more specifically, the temperature of the wire rods is controlled by dividing the water cooling zone into a plurality of zones and distributing the amount of cooling water in proportion. It relates to a method of cooling to a target temperature.

0002

[Background Art] In the wire rolling process, when cooling the wire to a target temperature with cooling water, the required amount of cooling water is determined according to the deviation between the actual wire cooling temperature and the target temperature, and this flow rate is accurately controlled. There is a need to. A common method for controlling water cooling of the wire is to measure the temperature of the wire and control the amount of cooling water.

FIG. 5 is a schematic diagram showing an example of a conventional wire water cooling control method, in which 1 is a water cooling zone, 2 is a cooling water amount calculation control device, 3 is a flow rate control valve, 4 is an inlet thermometer of the water cooling zone, and 5 is a diagram showing an example of a conventional wire water cooling control method. is an outlet thermometer, and 6 is a wire rod. That is, in this method, the temperature at the inlet and outlet of the water cooling zone of the wire is measured and input to the cooling water amount calculation control device 2, where the required amount of cooling water in the water cooling zone is calculated according to the deviation from the target temperature after cooling the wire. This method controls the flow control valve 3 so that the amount of cooling water obtained is the same.

0004

By the way, in the process of rolling wire rods, it is common to perform non-water cooling control on the tip end in order to improve the wire conductivity. This tip non-water cooling control is a method in which cooling is performed from the middle of the wire without supplying cooling water only to the tip of the wire. When this method is implemented using the conventional water cooling control method shown in FIG. 5, cooling water is supplied to the wire in the water cooling zone immediately after the tip of the wire 6 leaves the water cooling zone 1. Water cooling zone 1 immediately after water cooling is completed
The amount of water that is supplied to the wire rod portions within the wire rods before they complete passage through the water cooling zone differs depending on their position, and many portions of the wire rods that are cooled significantly deviate from the target temperature after cooling, resulting in a large amount of end truncation in the product.

FIG. 6 shows the wire temperature when entering the water cooling zone using the conventional water cooling control method, FIG. 7 shows the total amount of water supplied while passing through the water cooling zone, and FIG. 8 shows the wire temperature after water cooling. It is. That is, in the conventional water cooling control method, the total amount of water supplied to the portion of the wire rod 6 immediately after leaving the water cooling zone 1 while passing through the water cooling zone is as shown in FIG. As shown in FIG. 8, since inclined water cooling is used, the wire temperature when leaving the water cooling zone often exceeds the target temperature as shown in FIG. 8, resulting in poor yield.

In order to solve the above-mentioned conventional problems, the present invention takes into account the water volume balance within the water-cooling zone, and reduces the amount of water applied to the portion existing in the water-cooling zone immediately after the end is cooled while passing through the water-cooling zone. The purpose of this paper is to propose a water cooling control method that can maintain the temperature almost constant regardless of the position within the band and minimize the portion where the temperature deviates from the target temperature after cooling.

[0007]

[Means for Solving the Problems] The present invention is a method for controlling the amount of water on the outlet side of the water cooling zone to be larger than the amount of water on the inlet side. The system controls the amount of cooling water independently, and calculates the required amount of cooling water in the water cooling zone from the water cooling zone inlet temperature and outlet temperature of the wire, the wire target temperature after water cooling, the wire rolling speed, and the material size. The gist of this method is to water-cool the temperature of the wire by allocating the amount of water to each zone.

[0008]

[Function] The water cooling zone is divided into a plurality of zones, each of which is connected to a cooling water pipe with a flow rate control valve, creating a piping system in which the amount of water can be set independently for each zone. The timing to open the flow rate control valve of each zone is performed t seconds after the time when the material is detected on the inlet side of the water cooling zone. Here, t
is calculated using the following equation 1.

[0009]

[Math 1]

In Equation 1, lH is the distance (m) from the material detector installed on the water-cooled zone entrance side to the water-cooled zone entrance, lW is the total length of the water-cooled zone (m), l is the tip unwater-cooled indicated value, and v is the This is the wire rolling speed. The flow rate control valve of each zone opens after t seconds determined by the above equation 1, and the required amount of cooling water in the water cooling zone at this time is calculated by the following equation 2.

[0011]

[Math 2]

In Equation 2, F is the required amount of cooling water in the water-cooled zone, T1 is the indicated value of the water-cooled zone inlet thermometer (°C), T2 is the indicated value of the water-cooled zone outlet thermometer (°C), and Tm is the target temperature of the wire after water cooling. (℃). Next, when the required amount of cooling water in the water-cooled zone is calculated using Equation 2, the amount of cooling water in each zone of the water-cooled zone is calculated using Equation 3 below, and each flow rate control valve is controlled.

[0013]

[Math 3]

That is, the amount of cooling water in each zone of the water-cooled zone is smaller on the inlet side of the water-cooled zone, and increases toward the outlet side.
The ratio is distributed so that the zone on the exit side of the water cooling zone has the largest amount of cooling water. Therefore, the amount of water applied to the water-cooled wire rod while it passes through the water-cooled zone immediately after the end of the water-cooled wire rod is almost constant regardless of the position of the water-cooled zone, and the wire rod temperature after water cooling will not deviate significantly from the target temperature. It will disappear.

[0015]

[Embodiment] Fig. 1 is a schematic diagram showing an example of a water cooling control system for carrying out the method of the present invention, in which 11 is a water cooling zone having a plurality of zones 111 to 11n divided in the wire running direction, and 12 is a cooling water amount. 13 is a ratio distribution device, 14 is a cooling water supply pipe, 15 is an inlet thermometer, 16 is an outlet thermometer, 17 is a material detector, and V1 to Vn are flow control valves.

That is, the water cooling control system shown in FIG. 1 divides the water cooling zone 11 into a plurality of zones 111 to 11n,
Cooling water is supplied independently through cooling water supply pipes 14 connected to each zone. The flow control valves V1 to Vn of each zone are controlled to open and close according to commands from the ratio distribution device 13. The cooling water amount calculation and control device 12 receives the instruction values T1 and T2 inputted from the thermometers 15 and 16 provided on the inlet and outlet sides of the water cooling zone 11, the tip uncooled instruction value l input in advance, and the water cooling zone temperature. From the total length lw, the distance lH from the material detector to the water cooling zone entrance, and the wire rolling speed v, the timing to open the flow rate control valves V1 to Vn of each zone is determined using the above equation 1, and the timing for opening the flow rate control valves V1 to Vn of each zone is determined using the above equation 2.
The required amount of cooling water is determined and instructed to the ratio distribution device 13. The ratio distribution device 13 determines the amount of cooling water F1 to Fn in each zone using the above equation 3, and sets and controls the flow control valves V1 to Vn so that the amount of cooling water is supplied to each zone.

As an example, FIG. 2 is a diagram illustrating the amount of cooling water F1, F2, and F3 in each zone by the water cooling control system when the water cooling zone 11 is divided into three zones, and FIG. FIG. 4 is a diagram showing the total amount of water applied until the wire passes through the water cooling zone 11, and FIG. 4 is a diagram illustrating the wire temperature after water cooling in the same as above.

That is, when the water-cooled zone is divided into three zones, as shown in FIG. 2, the amount of cooling water supplied to the water-cooled zone 11 is controlled so that it is small on the inlet side of the water-cooled zone and large on the outlet side. The total amount of cooling water applied while the wire rod 6 passes through the water cooling zone 11 is as shown in FIG. Therefore, the wire temperature after water cooling is as shown in Figure 4.
If the material temperature after water cooling is considered to be a good product up to the target temperature (Tm±ΔT), the yield will be improved by Lm.

[0019]

[Effects of the Invention] As explained above, according to the method of the present invention, the flow rate of the cooling water in one water-cooled zone can be set partially independently, so that the portion existing in the water-cooled zone immediately after the end is cooled with water is The amount of cooling water applied until the material passes through the water cooling zone can be kept almost constant regardless of the location of the water cooling zone, and as a result, the material temperature after water cooling will not deviate significantly from the target temperature, resulting in a reduction in the amount of end truncation. can be reduced and the yield of wire rods can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a water cooling control system for implementing the method of the present invention.

FIG. 2 is a diagram illustrating the amount of cooling water in each zone when one water cooling zone is divided into three zones.

FIG. 3 is a diagram showing the total amount of water applied while the wire passes through the water cooling zone in FIG. 2;

FIG. 4 is a diagram showing the wire temperature after water cooling in FIG. 2;

FIG. 5 is a diagram showing an example of a conventional wire rod water cooling control method.

FIG. 6 is a diagram showing the wire temperature when entering the water cooling zone in FIG. 5;

7 is a diagram showing the total amount of water supplied while the wire passes through the water cooling zone in FIG. 5. FIG.

FIG. 8 is a diagram showing the wire temperature after water cooling in FIG. 5;

[Explanation of symbols]

11 Water cooling zone 12 Cooling water amount calculation control device 13 Ratio allocation device 14 Cooling water supply pipe 15 Inlet thermometer 16 Outlet side thermometer 17 Material detector

Claims (1)

[Claims] Claim 1. A method for controlling water cooling of wire rods in a water cooling zone of a wire rod rolling process, in which one water cooling zone is divided into a plurality of zones, and the amount of cooling water is independently controlled for each zone, and the water cooling zone entrance for the wire rods is The required amount of cooling water in the water cooling zone is determined from the temperature and outlet temperature, the wire target temperature after water cooling, the wire rolling speed, and the material size, and the required amount of cooling water is distributed to each zone in proportion to the temperature of the wire rod. A method for controlling water cooling of a wire rod.