JPS5939486B2 - Cooling method for hot rolled wire rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves forming a wire rod immediately after hot rolling into a continuous ring shape using a winding machine, and sequentially placing the wire rod on a conveying device so that the center of the ring shape is shifted at a certain pitch. The present invention relates to a method for controlling cooling while continuously transferring the liquid in a state in which the liquid is cooled.

Taking advantage of the fact that the wire rod after hot rolling is at a temperature higher than the As point of steel, the wire rod after hot rolling is formed into a continuous ring shape, and the wire rod formed into the ring shape is transferred to a conveying device (e.g. A so-called direct particulate method is known, in which a ring is conveyed on a conveyor with its center shifted at a certain pitch while being controlled and cooled using a fluid such as air.

In this direct particulate fern method, for example, as shown in FIG.
After cooling to around 00°C, it is formed into a continuous ring shape using a winding machine 3, which is placed on a conveyor 4, which is a transport device, and is continuously transported with the center shifted at a certain pitch. However, when the wire rod passed through the winder 3 is placed on the conveyor 4 and moves on the conveyor 4 at a certain speed, the ring-shaped wire rod As shown in the figure, there are many overlapping lines at both ends of the conveyor 4, and the density is significantly higher than that near the center of the conveyor 4, so that the cooling rate is slower than near the center.

Further, as shown in FIG. 3, the ring-shaped wire 5 is held on a rail 6 provided on a conveyor, and is conveyed by the claws of a chain 7 provided along the rail 6.
The wire rods in the portions that are in contact with the rail 6 and the chain 7 are not cooled by the fluid 11 injected from the cooling fluid injection nozzle 8, resulting in a significant difference in cooling rate. For this reason, the cooling rate of the ring-shaped wire 5 differs depending on its position on the conveyor. Such a difference in cooling rate is due to differences in the steel's transformation start temperature, transformation end temperature, and time required for transformation, that is, the transformation rate, etc., of the steel in each part of the wire, resulting in structural differences in each part of the wire, and the mechanical properties, especially the tensile strength. They differ in strength and aperture value, and have disadvantages in terms of quality. Conventionally, as a solution to this problem, for example, the edge of the ring-shaped wire is rolled using a plurality of horizontal rollers that are installed facing each other at a predetermined interval smaller than the ring diameter of the wire on both sides of the conveyor and parallel to the traveling direction of the wire. A method has been proposed in which the rollers are moved up and down to reduce overlapping of the wire rods and to equalize the rolling speed between the edges and the center. There are disadvantages such as the occurrence of surface flaws that are harmful to the product at the contact area between the roller and the wire and the maintenance of the large number of rollers.

The present invention aims to eliminate the drawbacks of the conventional methods as described above and to provide a cooling method for obtaining a wire rod of uniform quality.

That is, the present invention forms a hot-rolled wire rod into a continuous ring shape, and uses a fluid to convey the ring-shaped wire rod on a conveying device with the centers of the rings shifted at a certain pitch. In this method, the conveyance device is divided into a plurality of units with appropriate lengths in the conveyance direction, and a vibration device using a vibration motor is attached to some or all of the divided conveyance devices to enable vibration in the vertical direction. This method of removing a hot rolled wire rod is characterized in that the wire rod on the transfer device is vibrated and removed by vibrating the transfer device in the vertical direction while the wire rod is being transferred.

Next, the method of the present invention will be explained in detail with reference to the embodiments shown in FIGS. 4 to 7.

First, as shown in Fig. 1, a hot rolled wire rod is sent out of a finishing mill 1 by the above-mentioned known method, then cooled to around 800°C by a water reeling device 2, and then continuously rolled by a winding machine 3. The rings are sequentially placed on a conveyor 4, which is a transport device, and are transferred with their centers shifted at a certain pitch while being heated to approximately 800°C using a fluid such as air.
The method of the present invention involves placing the ring-shaped wire rod 5 on a conveyor 4, which is a conveying device, and transporting the ring-shaped wire rod 5 with its center shifted at a certain pitch while cooling the ring-shaped wire rod 5 to a temperature of 400 degrees Celsius or higher. from a temperature of about 800°C using a fluid of 40°C.
When cooling to a temperature of 0°C or higher, the conveyor 4, which is a transporting device, is moved in the transport direction as shown in Fig. 5, centering on the transformation point (around 600°C) of all sizes and steel types of the wire to be cooled. As shown in L no 1) / -X MaJ /7'l =
c:/Ft+1J- Small 17tkLy Small *L
The width of the approximately 5m section between 4a (length in the conveyance direction) is approximately 500 mm.
The conveyor section 4b is divided into 10 parts of 4b of mm, and a vibration device 13 shown in FIG. By vibrating the conveyor part 4b in the vertical direction, gaps are created at the overlapping parts of the wire rods and the contact areas between the wire rods and the rails, the wire rods and the chains, etc., and a fluid such as air is blown into the gaps. The wire is melted at a melting speed of 50 CAeC, and the entire wire is melted uniformly.

Here, the vibration device used in the present invention will be explained based on the embodiment shown in FIGS. 4 and 5.

FIG. 4 is a cross-sectional view showing an example in which a vibrating device is provided on the divided conveyor portion 4b, and FIG. It is a diagram.

As shown in the drawing, the vibration device 13 includes a vibration motor 9 provided on both sides of the divided conveyor section 4b, a support member 14 fixed to both sides of the conveyor section 4b, a pedestal 15 fixed on the floor, and a support member. 14 and a support spring 10 mounted between a frame 15, and when driven by a vibration motor 9, the conveyor portion 4b is vibrated in the vertical direction via the support spring 10.

In addition, the lower part of the conveyor part 4b and the lower member 1 of the conveyor 4
A certain interval is provided to prevent contact with the upper part of 7 due to vibration, and a bellows 16 is used to seal the gap to prevent fluid such as air from flowing out.

The conveyor portion 4b of the conveyor, which is the conveying device in this embodiment, has a width (length in the conveying direction) of approximately 500 mm, and the width of the conveyor portion 4b is approximately 500 mm.
．． 5 to 13 Ttr/L), divided into approximately 5 m ranges around the center of the transformation point (around 600°C) of all steel types and 10
However, this embodiment takes into account that the transformation point (around 600°C) position of the wire rod to be removed on the conveyor differs depending on the size and steel type, and it is possible to uniformly remove all these steel types. This is a preferred example in which the wire rod is configured and arranged as shown in FIG. Of course, it is possible to select the width of the device (length in the transport direction) and the number of pieces to be divided.

Further, the frequency, amplitude, vibration direction, excitation force, etc. of the vibrating device can be arbitrarily varied depending on the size and steel type of the wire, the conveyance speed of the conveyor, etc.

Furthermore, in the method of the present invention, although air is generally used as the fluid, it is of course possible to use a fluid other than air as long as it is a refrigerant capable of cooling within the cooling rate range of 1 to 50 C/SeC. It is.

The reason why the cooling rate was set at 1 to 50°C/Sec was to take into account the cooling effect of all sizes and steel types of wire rods to be removed. Below 10C/SeC, there is no patenting effect, and at 50°C /SeC or higher, it becomes too thin and martensite etc. are generated, which is not preferable in terms of material quality. Next, the operation of the method of the present invention will be explained with reference to the embodiments shown in FIGS. 4 to 7.

By driving the vibration motor 9, the conveyor parts 4b are moved up and down relative to each other, and the link-shaped wire rod 5 is moved up and down, so that the wire rod 5 is moved as shown in FIGS. 6 and 7.
A gap is provided between the overlapped part of the wire rod 5 and the contact area between the wire rod 5 and the rail, and the wire rod 5 and the chain pawl 12, and a fluid 11 such as air is blown into this gap to uniformly wrap the wire rod 5. reject

According to the method of the present invention, even a slight movement of the wire rod due to vibration can be uniformly removed, so the wire rod does not come off the conveyor claw or the ring shape is deformed, and the wire rod can be uniformly removed without any problems during conveyance. can. Next, the results of implementation using the method of the present invention will be explained.

Test material: diameter 5.5 mm, C: 0.61%, Mn
: A 0.55% hard steel wire rod is used, and after the wire rod is hot-rolled, it is rapidly chilled to approximately 800°C using a known water heating device, and air is used as a cooling fluid while the wire rod is being transferred via a winding machine and a conveyor. The cooling rate of the wire was set to 8℃/Sec, and the temperature of the wire was 6508C to 550C.
In the conveyor section 4b, the vibration device shown in FIGS. 4 and 5 was installed on a ring-shaped wire rod with a ring diameter of 1050 nm whose centers were shifted at a pitch of 40 mm, and a vibration frequency of 5 Hz was applied.
, vibration was applied with an amplitude of 10 mm and an excitation force of 1000 kg.

As a result, the mechanical properties of the obtained wire are shown in Table 1.
As is clear from Table 1, the wire rod produced by the method of the present invention has significantly less variation in mechanical properties such as tensile strength than the wire rod produced by the conventional method, and can be obtained with uniform quality. You can get something more expensive than other things.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams of the conventional cooling method, in which FIG. 1 is a schematic front view, FIG. 2 is a plan view of the conveyor portion in FIG. 1, and FIG. 3 is a sectional view of FIG. Figures 4 to 7 are explanatory diagrams of the cooling method of the present invention, Figure 4 is a cross-sectional view showing one example of divided conveyor parts, and Figure 5 is a vibration device provided in the divided conveyor portion shown in Figure 4. Plan view showing an example of arrangement of things, Figure 6A
, b and FIGS. 7A and 7B are schematic diagrams comparing the effects of the conventional method and the method of the present invention. 4a. 4b... Conveyor part, 5...
Wire rod, 9... Vibration motor, 10...
Support spring fluid, 12...Claw, 13...
Vibration device support member, 15... Frame, 16...
...bellows.

Claims (1)

[Claims] 1. A method in which a wire rod after hot rolling is formed into a continuous ring shape, and the wire rod formed into a ring shape is cooled using a fluid while being transported on a conveying device with the center of the ring shifted at a certain pitch. , the conveying device is divided into a plurality of units with appropriate lengths in the conveying direction, and a vibration device using a vibration motor is attached to some or all of the divided conveying devices, so that the wire rod is vertically moved during conveyance. A method for cooling a hot rolled wire rod characterized by cooling it while vibrating it.