JPS6045254B2 - Cooling method for hot rolled wire rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cooling a hot rolled wire rod, and more particularly to a method for uniformly cooling a wire rod coil having a high polymerization density while transporting it in an surrounding environment.

Hot-rolled steel wire is wound into a coil by the rolling head of a winding machine, and then placed on a transfer conveyor in a group of overlapping rings shifted at a fixed interval, and transferred using the rolling heat during rolling. It is known to perform slow cooling while cooling.

In this case, the wire coil is usually passed through an surrounding environment such as a heat insulating cover. However, conventional cooling methods cannot satisfactorily eliminate the temperature deviation between the outer surface of the coil and the center of both edges, which overlap and have high density, due to the difference in the polymerization density of the wire coil. It was difficult to measure the uniformity of cooling. The present invention solves the problems of the prior art, reduces temperature deviations due to differences in polymerization density of wire coils, and as a result achieves uniform cooling of the wire and obtains a product with small quality variations. The purpose of the present invention is to provide a method for cooling hot rolled wire rods.

In order to achieve the above-mentioned object, the present invention transports a hot-rolled wire rod which has been wound into a coil shape by a winding machine, through an surrounding environment in the form of a group of overlapping rings shifted at a constant interval. Before inserting the wire coil into the surrounding environment, predict in advance the position of the layer-dense part (portion with high overlap density) of the thick-layered coil formed in the surrounding environment, This coil position is also selectively cooled.

Another feature of the present invention is that, in addition to meeting the above-mentioned requirements, the refrigerant is sprayed onto the high-temperature portion of the coil while loosening the coil passing through the surrounding environment. When a wire rod is passed through an enclosed environment such as a heat insulating cover in the form of a thick coil, as shown in Figure 1, the overlapping state of the coil is as shown in Figure 1, where the center overlaps the most and the density is lower at both edges. The overlapping density increases as the transition progresses, and both edges have the highest overlapping density (this part is particularly referred to as the dense layer area A).

The dense layer A of this coil has a slower cooling rate than the other outer surface parts of the coil, and therefore becomes a high temperature part, which is also a cause of an increase in temperature deviation from the low temperature part of the outer surface of the coil. . Various cooling methods and devices have been proposed in the past to focus on cooling this layered area, but the reality is that they have not been as effective as expected. By adopting the above-described configuration, the present invention lowers the temperature of the layered portion by selectively cooling the layered portion before forming the layered coil. This is to ensure uniform cooling of the wire.

In addition, before forming the layered coil, by selectively cooling the portion that will become the layered layer in advance, the temperature of the layered layer is lowered while passing through the surrounding environment, and in the process of passing, 1 This method attempts to uniformly cool the wire by spraying refrigerant onto the high-temperature parts of the coil while loosening the coil more than once. The contents of the present invention will be explained below based on the drawings.

Figure 2 shows a wire rod sent through a hot rolling mill and a water-cooled trough (not shown), wound into a coil by a winding head 1 of a winding machine, and immediately followed by a transfer conveyor 2 (roller conveyor). ) and is then charged into the heat retaining cover 3 at a certain distance. Inside the heat retaining cover 3, the wire is formed into a thick coil 4. In addition, here, the layer thickness coil 4 is 1T in the coil transfer direction.
This means that 50 to 550 rings exist per rL. In the above, a relatively short air cooling zone 5 is provided between the winding head 1 of the winding machine and the inlet of the heat retaining cover 3 for operational reasons.

In the first aspect of the present invention, a refrigerant having a temperature lower than the coil temperature is blown through the nozzle 6 at the position of the air cooling zone 5, that is, at the time when the wire coil is not formed into a thick coil or when the coil is falling from the laying head 1. It is something to attach. The target position of this refrigerant spray nozzle 6 is a position corresponding to the dense layer part (part A in FIG. 1) when the thick layer coil 4 is formed in a later process. The position of each ring in the circumferential direction is almost determined when the wire is discharged from the laying head 1 in a coil shape, and the layer thickness coil 4 is formed as it is, so the desired portion of each ring (layer density There is no problem in cooling the part (the part that becomes the part) because it becomes a dense part.

Since the refrigerant spray nozzle 6 sprays the refrigerant onto both edges of the wire coil, its main line of spray is directed toward approximately the edges of each ring, and moreover, the refrigerant is oriented toward the edges of each ring from both sides of the ring. I'm trying to aim.

Moreover, the refrigerant spray nozzles 6 may be provided in a pair on both sides, or may be provided in a plurality of pairs. Further, the spraying direction of the nozzle 6 is preferably arranged downward toward the direction in which the wire coil falls. One specific example of the nozzle 6 is shown in FIG. 5A.

FIG. 5A is a perspective view of FIG. 2, and the opening in the figure is an enlarged view of the discharge port 7 of the nozzle 6. That is, the discharge port 7 of the nozzle 6 has a slit shape as shown in the figure, and the discharge port 7 faces in the advancing direction (falling direction) of the wire coil group 4a sprinkled and falling from the laying head 1. .
Further, this nozzle 6 is configured to be able to adjust its angle with respect to the traveling direction of the wire ring group 4a, and this angle adjustment is performed by mutually connecting a support mechanism 8, which also serves as a fulcrum, and a compression drive device (for example, an air cylinder) 9. It is done by action. Therefore, the wire ring group 4a is transferred to the transfer conveyor 2 (
Even if the manner in which the refrigerant falls into the air cooling zone 5) changes due to the action of the raining head 1, the nozzle 6 can properly spray the refrigerant and fully fulfill its intended purpose. In the illustrated case, blast (high pressure air) is used as the refrigerant. Further, the cooling rate of the air cooling zone 5 is desirably 1 (generation)/Sec or less. As described above, in the present invention, since the part of the thick-layered coil that becomes the dense layer is cooled in advance, the temperature difference between the dense-layered part and the thin-layered part of the thick-layered coil 4 inside the heat insulating cover 3 is It is contracted at the inlet and transferred in this contracted state within the cover, achieving substantially uniform cooling along the desired cooling curve. Inside the heat insulating cover 3, the coil 4 is loosened at the stepped portion 10 constituting the transfer conveyor 2, and a refrigerant (industrially usable at a temperature lower than the ambient temperature inside the heat insulating cover) is supplied from the refrigerant spray nozzle 11. Refrigerant) is sprayed onto the high temperature section of the coil.

This coil loosening and refrigerant spraying to the high-temperature part of the coil can be repeated one or more times depending on the quality setting (purpose). Almost uniform cooling is achieved along the line. Of course, in the present invention, it is also possible to use means (for example, locally heating the low-temperature portion of the coil) for reducing temperature deviation even within the heat retaining cover.

Figure 3 is a chart showing the wire temperature after winding in relation to the elapsed time, and the chain line a indicates the layered part ( 0 in Figure 4), the chain line b is the temperature curve of the outer surface when no cooling is applied (representatively, the lowest temperature is indicated by ● and ? in Figure 4), The solid line c is the temperature curve of the layered part when both edges of the wire coil are cooled before inserting the heat insulating cover as in the present invention, and the solid line d is the temperature curve outside the coil when the cooling method of the present invention is applied. The temperature curves of the surface portion are shown respectively.

As can be seen from the figure, when the method of the present invention is applied, the temperature deviation between the high-temperature part and the low-temperature part of the coil is suppressed to a small level up to the entrance of the cover, so the deviation does not increase significantly even within the subsequent cover, resulting in a uniform It is clear that it will be possible to achieve significant cooling. In addition, as shown in FIG. 6, in addition to the cooling in the air cooling zone 5 according to the present invention, the refrigerant is sprayed from the refrigerant spray nozzle 11 to the high temperature part of the coil while loosening the wire coil 4 at the stepped portion 10 within the heat retaining cover 3. Curve C'' shows the results obtained by cooling using the same method as in Fig. 3. As shown in A and b, it can be seen that the temperature deviation between the high-temperature part and the low-temperature part of the coil widens from the winding up to the entrance of the cover, and that the deviation tends to further widen even after entering the cover.As explained above, According to the cooling method of the present invention, since the dense layered portion of the thick-layered coil is cooled in advance during cooling, the temperature deviation due to the difference in overlap density in the coil cross section, which is a problem when cooling the thick-layered coil, can be reduced. It can be kept small and greatly contributes to uniform cooling of the wire.

Another advantage is that the cooling operation is easy because it is performed while the wire coil is outside. Furthermore, in the present invention, in addition to cooling in the air cooling zone, the coil is loosened and a refrigerant is sprayed inside the heat insulating cover to cool the high temperature part of the coil, so uniform cooling has the beneficial effect of improving the insulation layer. .

[Brief explanation of drawings]

Figure 1 is a plan view showing the wire coil in a polymerized state;
The figure is an explanatory diagram showing an example of equipment for carrying out the method of the present invention,
Fig. 3 is a diagram showing the relationship between time and wire temperature to explain the effects of the present invention, and Fig. 4 is a schematic diagram showing the high temperature part (dense layer part) and low temperature part (thin layer part) in the cross section of the coil. , Fig. 5A is an enlarged perspective view of the detailed main part of Fig. 2, the opening in the figure is an enlarged perspective view of the main part of the nozzle, and Fig. 6 is the relationship between time and wire temperature to explain the effects of the present invention. This is a chart showing the following.

Claims (1)

[Scope of Claims] 1. When a wire rod that has been hot-rolled and wound into a coil shape by a winding machine is passed through an surrounding environment in the form of a group of overlapping rings shifted at a constant interval and cooled,
A method for cooling a hot-rolled wire rod, characterized in that a portion of the thick-layered coil transported in the surrounding environment with a high overlap density is selectively cooled before being charged into the surrounding environment. 2. When the hot-rolled wire rod is wound into a coil by a winding machine, it is cooled by passing it through an surrounding environment in a group of overlapping rings spaced apart from each other by a certain distance.
selectively cooling the densely overlapped portion of the thick-layered coil being transported through the surrounding environment before charging it into the surrounding environment, and loosening the coil as it passes through the surrounding environment; A method for cooling a hot-rolled wire rod, the method comprising: spraying a refrigerant onto a high-temperature portion of the coil to cool the coil.