JPS6158528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling method for rolling easily bendable materials such as wire rods and steel bars (herein referred to as wire rods).

Conventionally, in this type of wire rod, hot steel is generally water-cooled upon exiting the finishing mill to facilitate handling in subsequent steps and to suppress scale formation. However, in the following explanation using a wire rod as an example, for example, in a Stelmore type direct heat treatment wire cooling equipment, the wire passes through a water cooling zone at a high speed of 60 m/s. In this case, in order to cool the entire wire, if high-pressure water is jetted out before the wire enters, the wire itself bends easily and enters at high speed, so the tip of the wire bends due to the high-pressure water. , troubles tended to occur within the water-cooled zone. As a result, a method of starting high-pressure water injection after the wire has entered has been necessary. Also,
The subsequent wires also continue with a small interval, so
In order to prevent problems with subsequent wires, the water injection must be stopped when the end of the first wire is approached. Therefore, the tip and rear ends of each wire become unwater-cooled parts. If this uncooled part existed, there was a problem in that the material could not have excellent mechanical properties.

This invention solves the above-mentioned conventional problems at once. By water-cooling the material at the front stage of the intermediate rolling mill or the finishing mill, it is possible to produce a material that is homogeneous and of good quality over the entire length of the material, such as The purpose is to manufacture non-thermal treated high tensile strength wire rods for cold forging, non-thermal treated high tensile strength wire rods for concrete piles, high strength HiC wire rods, low strength steel wire rods, etc.

The present invention will be explained below using specific examples shown in the drawings. In FIG. 1, a first water cooling zone 3 and a second water cooling zone 4 are arranged upstream of a finishing rolling mill 2 for wire rod 1.
Roughly cooled in the first water cooling zone 3, and then cooled roughly in the second water cooling zone 4.
In this case, cooling is performed with high accuracy to a predetermined temperature, and overall cooling control is performed with higher accuracy. 5 is a first material detector arranged in front of the first water-cooled zone 3 consisting of a photocell etc. for detecting the wire 1; 6 is the second water-cooled zone 4
A second material detector placed in front.

A cooling water supply pipe 7 is installed in the first water cooling zone 3, and this supply pipe once branches into two systems and then joins again to communicate with a jet nozzle (not shown).
A piston valve 8 is attached to the branch pipe.
A cooling water supply pipe 9 is installed in the second water cooling zone 4, and this supply pipe 9 includes a main pipe 9a and a branch pipe 9b.
The cooling water is discharged from each jet nozzle. The main pipe 9a is provided with a flow rate regulating valve 10, a flow rate detector 11, and a piston valve 12, and the branch pipe 9b is provided with a sub piston valve 13.
is provided.

Reference numeral 14 denotes a material temperature detector disposed at the front stage of the finishing rolling mill 2, and this temperature signal is recorded in a recorder 15, inputted to a temperature indicating controller 16, and further sent to a flow rate indicator via a first contact 17. It is input to the controller 18. On the other hand, the cooling water flow rate signal from the flow rate detector 11 is directly sent to the flow rate indicating controller 18.
Alternatively, it is input to the flow rate indicating controller 18 via the averaging circuit 19 and the second contact 20. A control device 21 receives signals from each device and outputs control signals as shown in the figure.

In the cooling equipment configured in this way, when the wire 1 reaches the first material detector 5, a timer (not shown) operates based on the detection signal, and after a predetermined time, the piston valve 8 operates, and the branch pipe Cooling water flows through the wire rod 1 at a constant flow rate, and water cooling is performed over the entire length of the wire rod 1 by on/off control of the piston valve 8. In this case, the first water cooling zone 3 would require a long water cooling zone if only the second water cooling zone 4 was used, and stripes would occur due to variations in temperature distribution, which would require a high-grade control device for temperature control. Therefore, when the material is lowered to a certain appropriate temperature and the wires reach the second cooling zone, the entire material is almost uniformly heated by the heat conduction of the wires themselves. From this point of view, cooling water should be constantly discharged during operation.
The first material detector 5 and piston valve 8 may be omitted.

In the second water cooling zone 4, before the wire 1 reaches the piston valves 12 and 13, both are closed, the second contact 20 is inserted, and the cooling water passes through the flow rate control valve 10, which is open. A constant amount of A is flowing. When the wire 1 reaches the second material detector 6,
A timer (not shown) is started, and after a predetermined period of time, the first contact 17 is closed, and the piston valve 12 and the sub-piston valve 13 are activated to open the flow path. As a result, the tip end of the wire 1 is cooled with water at a flow rate of A+B in addition to the flow rate B of the sub-piston valve 13. When this state continues for, for example, 2 seconds and the cooling of the tip ends, the first contact 17 is switched, the auxiliary piston valve 13 is closed, and the reheating of the wire 1 passing through the second water cooling zone 4 is completed. In order to correct the difference between the temperature indicated by the material temperature detector 14 installed at the location and the set temperature, the flow rate indicator controller 18 operates,
The flow rate is controlled and the temperature of the wire 1 is controlled. This temperature control is continued until the rear end enters the second water cooling zone. In order to improve the control characteristics (responsiveness) of the flow control valve 10 immediately after switching to the first contact 17, that is, switching to control by the control valve 10 on the body of the wire 1, The average value of the flow rate of cooling water when cooling the body of the wire rod 1 is averaged and stored by the averaging circuit 19, and
It can be set in advance when cooling. The rear end of the wire 1 is switched to the second contact 20 by an off signal that reaches the first material detector 6 or a previous detector (not shown) and a signal from a timer activated based on that signal, and The auxiliary piston valve 13 is operated to open the flow path, and cooling water in an amount of A+B is injected from the nozzle, and the rear end is cooled for, for example, 2 seconds.

Note that the body other than the leading end and the trailing end is further cooled in cooling equipment after the existing finishing rolling mill, and is cooled to a uniform target temperature over the entire length of the wire 1 during winding.

FIGS. 2 and 3 show examples of temperature control in the first water cooling zone 3 and the second water cooling zone 4, respectively.

FIG. 4 shows a different example, in which cooling equipment similar to the cooling equipment of the second water cooling zone 4 of the above-mentioned example is also provided in the first water cooling zone 3. Therefore, in this example, the cooling equipment of the first water cooling zone 3 is made the same number by simply adding a dash (') to the cooling equipment.

In this equipment, there are two methods for cooling: In the first method, when only the tip and rear ends of the wire rod 1 are cooled in the first water cooling zone 3, the tip of the wire rod 1 is cooled after a predetermined time using the tip detection signal of the wire rod 1 from the first material detector 5 and the timer. For example, the rear end portion is cooled for about 2 seconds, and the rear end portion is cooled for about 2 seconds by the rear end off signal from the first material detector 5. In this case, the second contact 20' is inserted,
Also, the piston valves 12' and 13' are in an open state.
In the second water cooling zone 4, temperature control similar to that of the second water cooling zone in the previous example is performed.

The second method is to apply a method similar to the cooling temperature control method of the second water cooling zone described above to the first water cooling zone 3 and the second water cooling zone 4.

According to these latter methods, compared to the former method (shown in the first diagram), it is possible to perform control that allows cooling to the target temperature more reliably. An example of this temperature control is shown in FIG.

It goes without saying that the cooling method according to the present invention may be used upstream of the intermediate rolling mill. This invention method is particularly effective in producing the wire rods mentioned above.

As described above, since this invention cools the wire rods at the front stage of the rolling mill, there is no need to cool the tip and rear ends with water as in the conventional method, and as a result, uniform mechanical strength is achieved over the entire length. A product with uniform properties can be obtained. Therefore, when combined with the well-known direct heat treatment wire cooling method such as the Stelmore method, it has the advantage of being able to obtain a product of quality equivalent to lead patented material, and its practical value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of the cooling method of the present invention, FIGS. 2 and 3 are diagrams showing examples of temperature control in the first and second water cooling zones, respectively, and FIG. 4 is a cooling method with different modes. A system diagram of the method, FIG. 5, is a diagram showing an example of temperature control. 1... Wire rod, 2... Rolling machine, 3... First water cooling zone, 4... Second water cooling zone, 5, 6... Material detector,
8... Piston valve, 10... Flow rate adjustment valve, 11...
...Flow rate detector, 12...Piston valve, 13...Sub-piston valve, 14...Material temperature detector, 15...
Recorder, 16... Temperature indicating controller, 18... Flow rate indicating controller, 19... Averaging circuit, 21... Control device.

Claims (1)

[Scope of Claims] 1. In a stage upstream of an intermediate rolling mill or finishing mill of rolling equipment for wire rods, rough cooling is performed in a first cooling zone located far from these rolling mills, and a first cooling zone located close to these rolling mills is used for rough cooling. In fine cooling in the second cooling zone, the body of the wire rod is cooled in the usual controlled manner according to the average cooling degree of the body of the wire rod that passed through the previous time, and the tip and rear ends are cooled. 1. A cooling method for rolling wire rods, characterized in that strong cooling is performed with added weight to the cooling, and further, in cooling equipment after the finishing rolling mill, a body portion other than the tip portion and the rear end portion is cooled. 2. The cooling method for rolling wire rods according to claim 1, wherein the rough cooling in the first cooling zone cools only the leading end and the rear end of the wire rods. . 3. The cooling method for rolling wire rods according to claim 1, wherein the rough cooling in the first cooling zone cools the entire length of the wire rods. 4 Normally controlled cooling of the body of the wire rod during fine cooling in the second cooling zone is performed by detecting the temperature of the wire rod after cooling in the second cooling zone, feeding back the detected temperature, and taking this into consideration. A cooling method for rolling wire rods according to claim 1, characterized in that controlled cooling is performed. 5. The rough cooling in the first cooling zone detects the temperature of the wire after cooling in the first cooling zone, and controls the cooling by feeding back the detected temperature. A cooling method for rolling wire rods according to scope 1.