JPS5952214B2 - Cooling method and cooling device for hot rolled wire rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cooling method and a cooling device for a hot rolled wire rod, and particularly a cooling method and a cooling device that can efficiently and uniformly cool a steel wire rod over the entire length of the wire rod on-line subsequent to the hot rolling process. , relates to a cooling device that can be used not only for carrying out this method but also for ordinary blast cooling.

In other words, carbon steel wire rods for machine structures used in strict quality applications such as automobiles, Ni, Cr, M.

Alloy steel wire rods, spring wire rods, etc. that contain special elements such as steel are usually subjected to various heat treatments before or during secondary processing.

The present invention provides a method for manufacturing a softened wire rod online following a hot rolling process, and a method for implementing the method, with the aim of omitting one of these heat treatments, for example, softening annealing applied to the wire rod. Another object of the present invention is to provide a cooling device that can also be applied to blast cooling for the purpose of rapid cooling.

After rolling, hot-rolled steel wire rods are placed on a conveyor in a non-concentric ring shape,
Methods of quenching and converging by blasting air during transport are well known in the art.

This method of quenching steel wire rods is applied to various medium-sized and high-carbon ordinary carbon steel wire rods, and the wire rods are processed into final products without the need for subsequent heat treatment.

However, some alloy steels and low carbon steels are not suitable for this rapid cooling method, and the desired quality may not be obtained unless they are slowly cooled at a slower cooling rate.

In particular, when the purpose is to soften high-grade steel wire rods, even slower cooling is required.

At the same time, strict cooling control is essential, and unless cooling is performed along the required cooling curve, the desired quality target value cannot be achieved.

Conventionally, as an online cooling method and apparatus for steel wire, a technique disclosed in Japanese Patent Application Laid-Open No. 51-64416 has been proposed.

In this method, hot-rolled steel wire is sent out in a coil shape by a winding head of a winding machine, and placed on the next transfer conveyor in a group of non-concentric, mutually synergistic rings. In order to ensure uniform cooling of the wire during transport of the group.

■Means for applying radiant heat to the wire according to the position between both sides of the ring, the intensity of which is approximately inversely proportional to the mass distribution of the wire with respect to the unit offer of the conveyor; ■Means that approximately correspond to the mass distribution of the ring; , depending on the position on both sides of the ring and in the middle, from the former there are radiators.

The method consists of a selective combination of three means: means for dissipating energy and suppressing it in the latter case; and (2) means for placing the ring in an enclosed environment to minimize cooling by convection of the wire.

In addition, the cooling device used in this method includes a conveyor that transports the wires forward in a synergistic shape, a cooling chamber that roughly covers the conveyor and the wire ring above it, and a cooling chamber that reflects the radiant heat from the wire ring. an inner wall of the cooling chamber, a fixed base and a selectively movable lid constituting the cooling chamber, an opening provided in a side wall of the cooling chamber whose opening degree can be adjusted, and an opening inside the cooling chamber. , provided facing the moving conveyor and separated from it, and having a plurality of heat dissipation surfaces,
Each heat dissipation surface is constituted by a selected combination of a plurality of independent temperature regulators, each of which is independently maintained at a predetermined temperature.

The purpose of this prior art is to perform precisely controlled slow cooling over the entire length of the wire as well as in its cross section, and to easily switch to high-speed cooling so that the temperature reaches 0℃/
An object of the present invention is to provide a method and a device that allow the cooling rate to be adjusted within a range of 20° C./see to 20° C./see.

As described above, the technical concept of Japanese Patent Application Laid-Open No. 51-64416 is to adjust the cooling rate by selectively controlling radiation rather than convection.

Specifically, should we focus on the wire mass distribution of a group of non-concentric polymerized rings per conveyor, and apply radiant heat to the wire rings that is approximately inversely proportional to this mass distribution? The purpose is to dissipate and suppress radiant energy approximately in accordance with the mass distribution.

In other words, the mass of the wire on the conveyor unit is maximum on both sides where each ring overlaps, and minimum at the center of the coil where the rings are separated from each other. Therefore, the center part of the ring radiates heat from both sides. easy.

Therefore, if the ring is allowed to radiate heat normally without being adjusted from the outside, the center of the ring will cool faster than the sides, so if you control the radiation rate from each part of the ring to avoid uneven cooling, you can achieve the desired result. 7 I am aware that it will be effective.

However, according to the research and experiments of the present inventors, the recognition of the above prior art is not necessarily correct, and even if this prior art is implemented, uneven cooling at each position of the wire ring cannot be completely avoided. It turned out that it was not profitable.

In particular, it has become clear that for high-grade steel wire rods that are difficult to soften, the desired softening of the bottom cannot be achieved by the cooling control of the prior art described above.

That is, as shown in FIG. 1, the present inventors have identified the outer surface portions of the wire coils that are placed and transferred non-concentrically and overlapping each other on the 20-ra conveyor (
, mu, the part indicated by the symbol ■) and the central part (Fig. 1 ■,
The temperatures of the wire coil and the roller conveyor (portions indicated by symbols A and E) were measured in an environment surrounding the wire rod coil and the roller conveyor (cooling room), and the results shown in FIG. 2 were obtained.

In this case, after the wire coil is actually hot-rolled and heated to about the temperature extracted from the winding machine, the upper atmosphere temperature in the surrounding environment (cooling room) is 650°C, and no θ convection occurs. state.

As is clear from Fig. 2, in each part of the coil in the width W direction, the temperature is higher on both sides than in the center depending on the mass distribution of the coil, but when viewed from the entire coil, the temperature is the highest. It can be seen that the part where the mass (density) is large is the central part (■, z) on both sides of the coil, and the part where the temperature is the lowest is the both sides of the lower surface of the coil (·, ■) that are in contact with the roller table.

In other words, the temperature difference between the center part of both sides, where the mass distribution of the coil is maximum, and the lower surface part is the largest, and is 100° C. or more.

This is due to the fact that the central part of both sides with high mass distribution (■, 4 is the most difficult to dissipate heat, and is instead kept at a high temperature by the retained heat brought in from the rolling of the ring forming the coil, while the lower surface of the coil (■, 4) , ■) are in contact with the circumferential surface of the roller, and since the roller bearing is installed outside the cooling chamber to prevent heat loss, heat dissipates most easily from both sides of the lower surface of the coil (・, ■) closest to the bearing. This is thought to be due to the low temperature.

Therefore, as in Japanese Patent Application Laid-Open No. 51-64416, radiant heat is simply applied in inverse proportion to the mass distribution in the width W direction of the wire coil, or radiant energy is dissipated on both sides in accordance with the mass distribution, and the radiant energy is dissipated in the central part. However, even if measures are taken to suppress radiation, the central part (■,
It is impossible to eliminate the temperature deviation between AB and the lower surface (., m, .) and it is impossible to avoid uneven cooling.

In particular, in the prior art, proper cooling of the lower surfaces (., ■) on both sides of the coil is promoted.

It is also hot-rolled and placed directly on the transfer conveyor.

In the case of transfer, the wire rod retains rolling heat,
Effectively utilizing this retained heat in the cooling chamber is advantageous in terms of energy conservation, but the prior art described above shows an example in which a radiant tube (radiant heat regulator) is placed in the cooling chamber to impart radiant heat to the wire. Therefore, the heat retained in the wire is not necessarily utilized effectively.

The present inventors have obtained the following findings in view of the above points and the results of various experiments.

(1) In order to slowly cool the wire rod after hot rolling online, it is advantageous to do it in as short a time and on a short line as possible in terms of equipment layout and equipment cost. It is preferable that the upper wire ring has as high a density as possible.

In other words, it is necessary to use a thick coil.

(2) Cooling control is required to achieve uniform cooling by minimizing the temperature deviation of each part of the wire coil during slow cooling.

(3) The rolling heat carried over from the hot rolling process has enough heat to be used for subsequent slow cooling.
Utilizing this effectively is more effective in terms of energy conservation.

(4) For steel types that are conventionally difficult to soften, considering the above-mentioned constraints on short processing times and short lines,
Extremely efficient and precise temperature control along the desired cooling curve is required.

(5) It is preferable to use cooling equipment that can quickly perform not only the above-mentioned slow cooling but also blast cooling in the same line.

Based on the above-mentioned points, the present invention has been developed so that when hot-rolled steel wire rods are placed on a transfer conveyor from a winding machine and transferred, the wire rods are arranged in a non-concentric overlapping manner and are slowly moved by thick-layered coils. A hot-rolled steel wire rod capable of uniformly cooling the coil by loosening the coil one or more times while being transferred and spraying a refrigerant to the loosened portion to perform accurate slow cooling based on a desired cooling curve. The purpose of this invention is to provide a slow cooling method.

Another object of the present invention is to provide a precise slow cooling method that makes it possible to sufficiently soften steel to a target value even for steel types that are difficult to soften using conventional cooling methods.

Furthermore, another object of the present invention is to rationally improve the temperature deviation between the center part of the coil and the lower surface part shown in FIG. Our goal is to provide a cooling system that can.

Furthermore, another object of the present invention is that in addition to being able to effectively carry out the above-mentioned slow cooling method, it is also possible to easily switch to rapid cooling (blast cooling) in the same cooling line as necessary. The object of the present invention is to provide a cooling device for steel wire that can be used.

The characteristics of the present invention are that the wire rod is placed on a conveyor as a thick layered coil, and the thick layered coil is slowly transferred in an surrounding environment such as a heat insulating cover, and in this surrounding environment, the wire rod is placed on a conveyor. Minimize the application of radiant heat from the coil to generate body temperature in the surrounding environment, and maintain the outer surface temperature of the coil at a substantially uniform temperature by the heat retained in the wire coil;
And the thick layered coil is loosened one or more times, or at the same time as the loosened portion is sprayed with a refrigerant to promote heat dissipation in the high temperature area of the coil (near the center of the thick layered areas on both sides of the coil). The purpose is to reduce the temperature deviation of each part of the ring forming the coil, and to compensate for the temperature of the low-temperature part of the surface (lower surface of the coil) where the coil contacts the transfer means, if necessary.

In addition, the cooling device of the present invention is characterized by providing a removable heat insulating cover that surrounds the thick layer coil on the transfer conveyor following the winding machine, making this a cooling zone, and forming the cooling zone into a desired wire cooling curve. The heat insulating cover is divided into a plurality of sections to enable cooling, and has an atmosphere stirring means inside or outside the heat retaining cover to make the atmosphere temperature within the cover uniform, and furthermore, at least during the transfer of the thick layer coil. The purpose is to provide a means for unraveling the coil once and a means for spraying refrigerant at this unraveling point.

In the present invention, the form of the wire coil placed on the conveyor is defined as a thick layer coil, but this thick coil is defined as a layered coil in which the wire rings falling from the laying head of the winding machine are flattened one after another while being slightly eccentric. This refers to coils that are superimposed on each other.
A coil that weighs ~550 kg is called a thick layer coil.

In particular, when performing cooling at a cooling rate of 0.05 to 0.2 °C/sec or less, the weight is 100 to 500 kg/m, and when performing cooling at a cooling rate of 0.2 °C/~1.0 °C/sec. Preference is given to coils with a layer thickness resulting in a weight of 30 to 70 kg/m.

The transfer density (coil thickness) of this layer thickness coil is uniquely determined by the relationship between the winding speed and the conveyor transfer speed (coil thickness), but if the transfer density becomes too large, the wire coils will become too dense and the conveyor transfer Since it is difficult to properly loosen the inside, the prior art shown in FIG. 2 cannot be expected to have much of an effect in reducing temperature deviation.

Furthermore, if the transfer density is low, it is disadvantageous in terms of equipment layout and equipment cost, and it becomes impossible to effectively utilize the heat held by the wire coil.

Therefore, in the present invention, a coil having a transfer density such that the wire ring weighs 30 to 550 kg per 1 m is defined as a thick-layer coil based on the examples described later, and the distinction from conventional coils is clarified.

In addition, the outer surface temperature of a thick coil means the outer surface of a group of wire rings forming the coil in a cross section perpendicular to the direction of transfer of the thick coil, and is the most easily understood temperature in this specification. The aspects are the symbol △ of the prior art shown in FIG.
It refers to the so-called outer surface portion corresponding to the parts marked with ■, mu, . . .

Furthermore, the term "dense layered parts on both sides of the coil" means the parts where the density of the rings is high in the vicinity of both sides in the cross section perpendicular to the transfer direction of the thick layered coil formed by the group of wire rings, The vicinity of the center of the part means the part that includes the part with the highest density.

For example, the easiest to understand aspect in this specification is the first
Refers to the part corresponding to the figure symbol 口,■.

The term "refrigerant" refers to a fluid that can be used industrially, such as air, inert gas, or steam.

Among these refrigerants, the most preferable one is that the atmospheric gas in the surrounding environment that is passed through the thick-layered coil is blown onto the wire ring from a nozzle, either as it is or by adjusting the temperature to form the thick-layered coil.

The temperature of the refrigerant may be equal to or lower than the temperature of the dense layered portion of the wire coil.

Therefore, the surrounding environment means a heat insulating cover equipped with device components that can cool the above-mentioned thick-layered coil along an optimal cooling curve, and the surrounding environment of the present invention actively prevents convection phenomena. For example, JP-A-51-6441
6 and JP-A-51-73910, which do not utilize body temperature phenomena, are not included.

' Also, compared to what has been known so far, this surrounding environment maintains the temperature of the above-mentioned outer surface of the thick-layered coil approximately evenly, and at the same time reduces the heat dissipation near the center of the dense layered areas on both sides of the coil. The difference is that a means for promoting the temperature deviation of each part of the ring group forming the coil is provided;
It is a new siege environment.

In addition, in order to slowly cool the wire using the apparatus of the present invention, J
The optimum cooling mode (cooling pattern) is selected depending on the quality setting target obtained using the steel type specified by IS, and the cooling mode recommended by the present inventors is summarized below.

That is, during hot rolling of steel wire rod, when cooling after passing through the final rolling stand, there is a step of rapidly cooling the final rolling temperature to a temperature of 700° C. or higher and 800° C. or lower using a cooling means (water cooling zone), and the layer thickness is The thick coil is placed on a conveyor while being formed into a coil, and the entire thick layer coil is heated to a temperature of 700°C or higher at 775°C.
holding or cooling the coil to a temperature below 800°C, and during the time of passing the coil through the surrounding environment while being transferred on a transfer conveyor, the entire portion of the coil is heated to a temperature of 800°C or above 67°C.
0.025~0.25℃ per second up to temperature range below 5℃
After the slow cooling step, the thick layered coil is cooled at a cooling rate of It is a heat treatment that combines the rapid cooling step in an integrated manner.

Based on this final cooling mode, JIS specifies that cooling is performed under the conditions specified in the claims.

For example, 545C, SCM'435. SUP'6 (7)
The quality is second to none, and the tensile strength is obtained through stable industrial production.

Steel type (JIS) Tensile strength (kg/mtM) S
45C<;68 SCM435 ≦80 SUP 6 ≦100, and the second
The temperature deviation of the layer thickness coil corresponding to the figure can also be greatly improved.

The present invention will be explained in detail below based on embodiment equipment shown in the drawings.

In addition to being able to effectively implement the slow cooling method described above, this embodiment of the equipment can also perform blast cooling for the purpose of rapid cooling in the same cooling line as needed.

This figure shows an example of a steel wire cooling device that can be easily switched to

FIG. 3 shows a line in which a cooling device 80 according to the present invention is arranged behind a water-cooled nozzle 1, a pinch roll 2, and a rolling head 3 of a winding machine following a hot rolling mill.

As shown in the figure, a conveyor, that is, a roller conveyor 5□, is arranged directly below the laying head 3 to place and transfer the steel wire 4 falling in a ring shape, and this roller conveyor 5 is moved at a predetermined speed. By driving the ring group weight (30
A layer thickness coil with a layer thickness of ~550 kg/m) is formed.

A transfer table that conveys the thick coil at a predetermined speed, that is, an elevating roller table 6 is installed at a position continuous with the roller conveyor 5, and the elevating roller table 6 loosens the thick coil one or more times. The structure is such that it is possible to add one or more steps in the direction of travel.

The conveyor 5 may be a chain conveyor instead of a roller conveyor.

In the illustrated example, the elevating roller table 6 is of a tilting type, but since the table only has to play the role of loosening the coil as shown in the figure, a fixed type may be used as long as there is a step.

However, the roller table 6 shown in this embodiment can adjust the height of the step and keep the transfer surface at the same level by operation. There is an advantage that the coil can be taken out in an emergency.

Next, in a certain range along the traveling direction of the lifting roller table 6, an surrounding environment surrounding the roller table 6 and the thick layer coil placed thereon, that is, a heat retaining cover 7 is provided. The heat retaining cover 7 is divided into one or more zones (four in the illustrated example) in the direction of travel, thereby forming a cooling zone in which the thick-layered coil is cooled along a desired cooling curve while being transferred. ing.

A transfer roller conveyor 9 is connected to the exit side of the heat retaining cover 7, and the transfer roller conveyor 9 is equipped with a blast cooling unit 8 at the bottom for rapidly cooling the thick coiled steel wire 4 that has been cooled as desired. At the end of the roller conveyor 9, a focusing device 10 is arranged to collect the cooled steel wire 4 to the final stage.

Note that the cooling section 8 is not limited to the illustrated example, and may be provided above the conveyor 9 perpendicularly, diagonally, or on both sides.

In addition, the elevating roller table 6 is also provided with a blast cooling section in the same way as the conveyor 9, or is installed below the table 6, so that the cooling section 8 can only function during blast cooling. It can be done.

Details of the heat insulation cover 7 per zone are shown in Figures 4 and 5.
As shown in the figure, the heat insulating cover 7 can be attached to the pillar 11 at an arbitrary height.
It consists of a lower base 7a with a groove-shaped cross section that is supported by and penetrates and holds a plurality of rollers 6a constituting the elevating roller table 6 in the middle direction, and an upper cover 7b that is combined with the lower base 7a. Although not shown, it can be attached and detached by a crane or opening/closing device, and can be applied to both slow cooling and blast cooling without any problems.

For this reason, for example, blast nozzles 13 following the blast blower 12 are arranged near both sides of the heat insulating cover 7.
3 has a split structure at the top and can rotate, and when the heat insulating cover 7 is in the installed state, it is retracted as shown in Figure 4, and the heat insulating cover 7 is in the detached state (i.e., the blast cooling (time), it can be rotated as shown in Figure 7, and blast air can be blown from both sides of the wire coil on the conveyor.

In addition to the illustrated example, the blast nozzle 13 can also be incorporated below the roller table 6 so that it can only function during blast cooling. Not restricted by.

However, the illustrated structure has the advantage of being simple in structure.

In addition, the surrounding environment, that is, the upper cover 7 of the heat insulation cover 7
A plurality of atmosphere stirring fans 14 are installed on the inner surface of the ceiling of the heat retaining cover 7 to generate convection within the heat retaining cover 7 to maintain a substantially uniform temperature inside the cover. A rectifying plate 15 is provided to improve the flow.

Further, a lifting device 16 is provided directly below the ceiling surface of the upper cover 7b.
A heat storage plate 17 whose angle is variable is suspended,
The heat storage plate 17 is displaced according to the transfer state of the layered coil to achieve more uniform heat retention (FIG. 5).

In addition, in the present invention, it is preferable to attach a gas burner 18 or an electric heater to the side wall of the heat retaining cover 7 in order to compensate the ambient temperature inside the heat retaining cover 7 or as a preheating measure in preparation for slow cooling operation. .

The bearings of each roller 6a of the elevating roller table 6 are arranged outside the heat retaining cover 7 as shown in the figure to prevent damage due to heat, and one of them is connected to the roller drive device 19, and the others are interlocked by a chain. This roller drive device has a variable roller rotation speed so that the transfer speed of the layered coil can be changed as appropriate.

Since the bearings of the lifting roller table 6 are provided externally, each roller 6a is cooled to below the ambient temperature by heat dissipation from the bearings.
The contact lower surface side of the thick-layered coil placed on the roller 6a (particularly the lower surface portions on both sides of the coil near the bearing) is easily cooled down to the lowest temperature, so as shown in FIGS. Although it is necessary to interpose a coil lower surface heat compensator, for example, an electric heater 20, on both sides between 6a, it is not necessary to keep the electric heater 20 in operation all the time, especially when the temperature of the lower surface of the coil drops. Temperature compensation is performed temporarily only when this is detected.

In addition, a prevention plate 21 is provided at the center position between each roller 6a to prevent the tip of a ring falling from above at a stepped portion of the elevator conveyor 6 from plunging between the rollers. You can leave it there.

On the other hand, as for the elevating roller table 6, as shown in FIGS. 5 and 6, the heat retaining cover 7 is designed to be able to move up and down using one group of rollers 6a as a unit in the direction of travel of the layer thickness coil as a fulcrum. A table lifting device 22 is connected and installed at the lower part of the entrance side.

This arrangement of the elevating roller table 6 is intended to provide a loosening effect at least once during the cooling of the thick layered coil transferred thereon, and the height difference is within a range of about 0 to 500 mm to prevent the coil from slipping. It is possible to take into account that this will not occur and to change it appropriately depending on the purpose of cooling, and in the case of blast cooling, it can be arranged at almost the same level as the first roller conveyor 5.

In addition, as shown in the figure, a nozzle 23 is installed at the coil unwinding position (step position) of the elevating roller table 6 to direct the refrigerant to the hot spots on both sides of the wire ring that is unraveled and falling at the step position. (Atmospheric gas of the heat insulating cover 7 adjusted to a temperature slightly lower than the coil temperature) is blown onto the coil.

The refrigerant is supplied to the nozzle 23 by sucking atmospheric gas around the cover from a suction port provided on the downstream side of a roller table consisting of a group of rollers, and passing the refrigerant through a refrigerant circulation blower 24 installed in the middle. It is sufficient that the water is branched and sent to a pair of nozzles 23 via a pipe 25 and a header pipe 26.

Note that the refrigerant suction and the path for sucking the refrigerant are not limited to those shown in the drawings.

In addition, the nozzle 23 for spraying the refrigerant is installed so that the refrigerant hits the densely layered portion of the coil, thereby efficiently radiating heat from the vicinity of the center of the slaughtering portion on both sides of the thickly layered coil.

Another example of refrigerant spraying is as shown in FIG.
7, the refrigerant may be branched to each step position via the pipe 28 and each refrigerant spray may be guided to the nozzle 23.

In this case, it is preferable that the temperature of each refrigerant sprayed through the nozzle 23 and the hot air is controlled to an optimum temperature by interposing a temperature controller 29 in a branch pipe from the pipe 28, for example.

Moreover, in order to further promote the convection within the heat retaining cover 7, it is also possible to adopt a structure in which the heat is sucked from an upper high-temperature part within the heat retaining cover 7 and is blown out from below the cover using a circulation blower.

Further, as shown in FIG. 9, the hot air intake port of the hot air discharge pipe 30 is opened at the low temperature lower part of the heat retaining cover 7, and
A fan 31 is installed in the upper part of the high temperature, and cool air is sent from the upper part.

It is also possible to discharge low-temperature hot air from the lower part to maintain a uniform temperature in front of the atmosphere inside the heat retaining cover 7.

Note that, unlike the method shown in FIG. 9, the temperature may be lowered only in the upper region of the heat retaining cover 7.

Furthermore, the entrance and exit of the heat insulation cover 7 is made of a thick layered coil.

An opening large enough for loading and unloading is required, and atmospheric air is blown in through the opening, which causes fluctuations in the atmospheric temperature inside the cover.

For this purpose, for example, as shown in FIG. 10, hot air is sucked from the heat insulating cover 7 through the hot air suction pipe 32, and is ejected from the nozzle 35 provided below the inlet (or outlet) of the heat insulating cover 7 by the blower 34. At least form an air curtain.

The air curtain may eject air not only from below but also from above or from the side of the entrance/exit.

The material of the heat retaining cover 7 is a cross-sectional material covered with an iron skin.

Further, the number of sections of the heat retaining cover 7 may be determined as appropriate based on the quality of the wire, cooling conditions, equipment layout, etc.

Furthermore, the means for loosening the inside of the heat retaining cover 7 is not limited to the step conveyor method shown in the drawings, and other known loosening means may be adopted, and the number of loosening times is also independent of the number of sections of the heat retaining cover. You can decide it arbitrarily.

FIG. 11 shows an example in which the holding position of the thick layered coil within the heat insulating cover is moved upward.

As shown in the figure, a burner 36 is installed at the bottom of the heat retaining cover 7, and a heat storage plate 37 such as an iron plate is arranged on the lower surface of the roller 6a.

As the heated air rises to the upper surface of the cover due to combustion in the burner 36, the upper part of the cover becomes relatively hotter than the lower part, so that the coil atmosphere temperature is maintained at a high temperature.

This makes it possible to maintain a high temperature in the lower surface of the thick-layered coil, which is particularly susceptible to low temperatures.

FIG. 12 shows an example for adjusting when the ambient temperature of the heat retaining cover 7 becomes, for example, a set temperature or lower.

As shown in the figure, the rectifier plate 15 is arranged so as to surround the thick-layer coil 4, and the heating device 48 is connected to the upper cover 7 of the heat retaining cover 7.
It is placed between the

A feature of this example is that when the ambient temperature of the heat insulating cover 7 becomes lower than the set temperature due to the rolling cycle, rolling or other troubles, the temperature can be compensated for.

That is, during normal operation, the ambient temperature of the heat insulating cover 7 is determined by the control valve 50 of the cold air intake port 49 and the air volume control valve 51.
This is maintained by adjusting the opening of the fan 14 and generating convection by stirring the fan 14.

However, when the above trouble occurs, there is no heat input, and the ambient temperature inside the cover falls below the set temperature.

At this time, the heating device 48 is activated to ensure a normal ambient temperature.

The heating device 48 is selected from among an electric heater, a radiant tube, a gas burner, and other industrially practical elements in consideration of economic efficiency, maintainability, and the like.

FIG. 13 shows an example of an adjustment method when the ambient temperature of the heat retaining cover 7 exceeds the set temperature.

During smooth operation, the ambient temperature of the heat retaining cover 7 may exceed the set temperature due to heat balance.

In such a case, the opening of the gate valve 53 attached to the pipe 52 is adjusted, and while the atmospheric gas from the cover 7 is removed by the blower 54, the atmospheric gas is brought to a predetermined temperature via the cooling device 56 by the operation of the control valve 55, and the pipe is closed. It is circulated and supplied to the heat insulation cover 7 from 57.

Thereby, the ambient temperature of the cover 7 can be maintained normally.

Also, in the same figure, a conduit 58 for guiding the exhaust gas of the heating furnace is shown in the pipe 5.
An example of connection to 2 is also shown.

When using this exhaust gas, operate the gate valve 53,
By suppressing the flow rate of atmospheric gas from the heat retaining cover 7, exhaust gas can be supplied to the cover 7 at a predetermined temperature via the cooling device 56 when the temperature is high, and via the heating device 59 when the temperature is low.

Note that the heating device 59 can also be used when the atmospheric gas of the heat retaining cover 7 is recycled as described above.

Next, the operation of the present invention will be explained using slow cooling of a steel wire as an example.

After the hot-rolled steel wire is cooled to a desired temperature by a water-cooled nozzle 1, it is sent to a winding machine by pinch rolls 2, and then sent to the next roller conveyor 5 by its laying head 3.
A continuous eccentrically superimposed layer thickness wall 4 is formed and placed on top.

The thick layer coil 4 is transferred on the roller conveyor 5 and enters the heat insulating cover 7, and is then transferred to the third layer by the next lifting roller table 6.
While being conveyed at m2/HIH+, it is cooled along a desired cooling curve.

Each zone within the heat retaining cover 7 is maintained at a predetermined ambient temperature.

The thick-layered coil 4 contained within the heat retaining cover 7 itself has rolling heat, and since the heat is radiated within the cover, the ambient temperature is controlled using the heat retained in this wire.

It is not necessary to apply thermal energy from the outside.

Inside the heat insulating cover 7, the atmospheric temperature is kept uniform both above and below by the stirring fan 14 and/or other convection means, and the outer surface of the layered coil 4 to be transferred is uniformly slowly cooled.

A heat storage plate 17 inside the cover helps to maintain a uniform backside temperature of the coil.

Among the outer surfaces of the thick-layered coil 4, the lower surfaces on both sides of the coil, which are particularly susceptible to low temperatures, may be compensated for the temperature of the lower surface by operating the lower surface heat compensator 20 provided between the rollers 6a as necessary.

Further, the thick layered coil 4 transferred on the elevating roller table 6 is loosened one ring at a time at the step position, falls onto the next stage roller table and is loosened, and at the same time returns to this loosened position. The atmospheric gas, which is circulated and sent from inside the heat retaining cover 7 and whose temperature is below the ambient temperature of the cover 7, is used as a refrigerant and is sprayed onto the falling wire rod while being loosened by the nozzle 23.

By performing the operation of blowing the refrigerant at the same time as removing the coil 4, it is possible to effectively dissipate heat from the center of both sides of the coil 4, which is the hottest part of the thick layered coil 4, and its vicinity.

Therefore, the thick layered coil 4 whose outer surface temperature has been made uniform by the above-mentioned atmosphere stirring (temperature compensation of the lower surface part as necessary) is also heat radiated from the center side by the above-mentioned stripping and refrigerant spraying. The overall length and cross-sectional temperature of the wire ring to be formed are uniform at each location.

This is based on the fact that the coil provides loosening or loosening one or more times, and the refrigerant is sprayed from a nozzle near the center of the slaughtering area.
This is a drawback of the prior art shown in FIG.

This means that the temperature deviation between the center and bottom of the coil has been significantly improved.

As a result, the coil 4 does not have a suitably cooled part and no untransformed part remains in the center, and the desired softening can be achieved regardless of the steel type.

The thick-layered coil thus loaded into the heat-retaining cover 7 and transferred by the lifting roller table 6 is cooled by successively moving through the divided cooling zones, completes its transformation, and is carried out from the heat-retaining cover 7.

After the transformation, the layered coil is transferred by the next roller table 9, while using a stepped conveyor, the speed of the succeeding conveyor is increased (1) to reduce the transfer density, and the blast cooling section 8 is used to reduce the transfer density to the desired value. It is quenched to temperature and focused by a focusing device 10.

Furthermore, in the above explanation, the cooling rate of the steel wire is 0.1°C/sec.
In this case, uniform cooling of 0.05 to 1.0° C./See can be performed by selecting the conveyor speed.

Moreover, slow cooling at a cooling rate of 0.2 to 1.0° C./sec can also be performed.

Furthermore, the cooling device of the present invention can be easily switched to blast cooling (cooling rate 10 to 20° C./5ee) on the same line.

When performing blast cooling, remove the upper cover 7b of the heat insulating cover 7 as shown in FIG.
3 to the fixed position, and the lifting roller table 6
The lifting device 22 is operated to adjust the level difference and increase the speed of the roller table.

In this state, while the hot-rolled wire coil is being transferred on the roller table 6, the blast blower 12 blows cold air from blast nozzles 13 onto the coil from both sides to rapidly cool the coil.

In this case, the cooling rate of the wire is 910~b.Also, an example of the control system for this purpose according to the present invention is shown in FIG. .

In the figure, 38 is a non-contact Koidell thermometer installed near the coil removal part, 39 is a roller speed meter (pulse generator), 40 is a control unit, 41 is a blower, 142 is a control valve, 43 is a flow meter, 44 is a thermometer.

The coil temperature of each adjacent zone is measured by the coil thermometer 38, the roller rough speed is detected by the speed meter 39, the signal is input to the control unit 40, the cooling rate between the zones is calculated, and this is used as the target cooling. Compare with speed.

When the cooling rate has not reached the target rate, the amount of warm air blowing and the temperature to be corrected are calculated based on the difference, and a signal thereof is output to the control valve 42.

Accordingly, hot air whose blowing amount and temperature are adjusted to a desired value is blown from the blowing nozzle 23 toward the coil, and the coil temperature is maintained appropriately.

The thermometer 44 detects the temperature of the refrigerant from the blower 41 and the temperature of the refrigerant from the nozzle 23.

In addition, when performing slow cooling in a thick-layered coil state, it is preferable to shorten the interval between the leading and trailing coils as much as possible in order to improve productivity. The starting end of the trailing coil overlaps with the starting end of the trailing coil, causing various troubles.

For this purpose, as shown in FIGS. 15 and 16, a boundary plate 45 is inserted between the leading and trailing coils, and conveyor conveyors 46 behind the heat insulation cover 7 are arranged in two rows, and a side shift device 47 is placed on this conveyance line. are set up to prevent problems.

That is, the preheated boundary plate 45 is placed on the final end of the thick layered coil coming out of the laying head 3, the next coil is placed on top of it, and the next coil is transferred inside the heat retaining cover 7, and when it leaves the cover, ``1 coil'' Every other time, they are delivered onto separate conveyors by the side shift device 47 and conveyed.

The boundary plate 45 is removed after the coils are separated and only the coils are focused.

The side shift device 47 is lifted after shifting and returned over the next coil.

As explained above, according to the method of the present invention, it is possible to accurately and uniformly slowly cool the wire in the state of a thick layered coil,
Even wire rods of steel types that are conventionally difficult to soften can be sufficiently softened.

Furthermore, the present invention allows extremely effective use of rolling heat, which is advantageous in terms of energy saving.

Furthermore, in the present invention, heat can be removed from the center on both sides of the thick-layered coil, making uniform cooling possible for the first time by equalizing the cooling rate of each part of the thick-layered coil.

Further, the cooling device of the present invention can effectively implement the above-mentioned slow cooling, and at the same time can easily switch to blast cooling, which is useful for simplifying the line.

Moreover, the entire equipment is short and has a structure that allows effective use of rolling heat, and it is also equipped with a mechanism that can unravel thick coils while cooling, making it ideal as a cooling device for wire coils. I can say it.

The present invention will be explained in detail below.

In this example, slow cooling was tested using the apparatus shown in FIGS. 3 to 7, 10, and 14.
Representative examples of the conditions and results are shown in Table 1.

In addition, each steel type in the table had the composition shown in Table 2.

As is clear from Table 1, Test Nos. 1 to 6 are heat treatments aimed at omitting low-temperature annealing, with cooling rates of 0.05 to 0.
．． Slow cooling at 2°C/Sec was performed using the conventional method (Test No. 4.
5).

Further, Test Nos. 7 to 10 indicate slow cooling at a cooling rate of more than 0.2 to 1.0° C./sec for the purpose of softening annealing to improve roughness, along with the conventional method (Test No. 8.10).

As described above, the method according to the present invention performs cooling along a cooling curve according to the processing target.
O.1 and 3 were tested under the test conditions shown in Table 1 along the cooling curve shown in FIG.

As is clear from Table 1, test No. 2゜3,
5. 7. The present invention of No. 9 was tested in Test No. 4. 6. 8
It can be seen that the temperature deviation between the outer surface of the layered coil and the slaughtering area is greatly improved compared to the conventional method of 10°C.

As an example of improving this temperature deviation, the temperature deviation of Test No. 1 is shown in FIG. 18, and when compared with FIG. 2, it can be seen that it has been greatly reduced.

It can be seen that due to such an improvement in temperature deviation, the variation in tensile strength is suppressed to be smaller than that in the conventional method, and sufficient softening is achieved.

The cooling device used in the above test was changed as shown in Figure 7.
25.

Mn0,47. P'0.012. So, 012%)
A wire rod with a wire diameter of 5.5 mmφ and a force of 106 to 108 kg/mm2 was obtained.

Therefore, the device of the present invention is a useful device that can be applied not only to slow cooling but also to blast cooling.

As described above, the present invention can greatly improve the temperature deviation between the outer surface of the coil and the slaughtered area during slow cooling, which was a drawback of the prior art, and thereby stabilize softening. It has effects of high industrial value, such as the ability to achieve

In particular, these effects can be obtained by unraveling the thick coil one or more times while maintaining a uniform atmosphere inside the heat insulating cover, and then spraying the refrigerant onto the unraveled area. The inventive device provides novel and beneficial effects.

For example, it is a device with high industrial value, such as being able to perform slow cooling over a short distance, saving space, improving temperature deviations in each part of the coil, saving energy, and being able to perform blast cooling. .

Note that the embodiments of the present invention include the following.

Embodiment 1 A method for cooling a hot-rolled wire rod, characterized in that the outer surface temperature of the coil is maintained approximately uniformly by selectively temperature-compensating both sides and/or the lower surface of the thick-layer coil.

Embodiment 2 In an apparatus for continuously cooling hot-rolled steel wire, there is provided a transfer table that forms or is capable of forming a stepped portion on which the steel wire is placed and transferred as a layer thickness coil, and a layer thickness on the transfer table. A removable heat insulating cover that surrounds the coil transfer path and is divided into one or more sections, and the inside of the heat insulating cover and/or
Alternatively, a cooling device for a hot rolled wire rod comprising an atmosphere stirring device provided externally and a refrigerant blowing device provided at a step position of the transfer table.

Embodiment 3 In an apparatus for continuously cooling hot-rolled steel wire, a transfer table that forms or is capable of forming a stepped portion on which the steel wire is placed and transferred as a thick-layer coil, and a layer-thick coil transfer on the transfer table. a removable heat insulating cover divided into one or more sections surrounding the path; an atmosphere stirring device provided inside and/or outside the heat insulating cover; a refrigerant spraying device provided at a step position of the transfer table; A cooling device for hot-rolled wire, comprising a blast cooling section provided at the inner thigh of the transfer table and/or in the vicinity of the transfer table.

Embodiment 4 In an apparatus for continuously cooling hot-rolled steel wire, there is provided a transfer table that forms or is capable of forming a stepped portion on which the steel wire is placed and transferred as a thick layer coil, and a layer thickness coil on the transfer table. A removable heat insulating cover that surrounds the coil transfer path and is divided into one or more sections, and the inside of the heat insulating cover and/or
Alternatively, it is characterized by comprising an atmosphere stirring device provided externally, a refrigerant spraying device provided at a step position of the transfer table, and a side and/or bottom surface heat compensation device of a thick-layered coil placed on the transfer table. A cooling device for hot rolled wire rods.

Embodiment 5 The cooling device according to Embodiment 4, wherein the atmosphere stirring device is a stirring fan provided on the heat insulation cover.

Embodiment 6 The cooling device according to Embodiment 5, characterized in that the refrigerant spraying device comprises a nozzle that sprays the atmosphere sucked from inside the heat insulating cover as it is or after adjusting the temperature.

Embodiment 7 The cooling device according to Embodiment 6, characterized in that a heat source and/or a cooling device for adjusting the atmospheric temperature inside the heat retaining cover is provided.

Embodiment 8 The cooling device according to Embodiment 7, characterized in that the transfer table for imparting loosening to the layered coil one or more times is an elevating roller table.

[Brief explanation of the drawing]

Fig. 1 shows a cross section perpendicular to the longitudinal direction of the thick-layered coil, and is an explanatory diagram showing the side-heated parts, and Fig. 2 shows the temperature deviation of the coil parts corresponding to Fig. 1 when slow cooling is performed using the prior art. The graphs and FIGS. 3 to 18 show one embodiment of the present invention. FIG. 3 is an explanatory diagram of a cooling device arranged in a wire rod rolling line, and FIGS. A detailed explanatory diagram of the thermal cover, Fig. 6 is an explanatory diagram showing the elevating roller table and an enlarged view of the nozzle for refrigerant spraying, Fig. 7 is an explanatory diagram showing an enlarged view of the state switched to blast cooling, and Fig. 8 9 is an explanatory diagram showing another example of refrigerant spraying, FIG. 9 is an explanatory diagram showing another example of generating convection within the heat retaining cover, FIG. 10 is an explanatory diagram showing a method of sealing the entrance and exit of the heat retaining cover, Figures 11, 12, and 13 are explanatory diagrams showing other examples of atmospheric temperature compensation inside the heat insulation cover, Figure 14 is an explanatory diagram showing the control method, and Figures 15 and 16 are leading and trailing diagrams. An explanatory diagram showing an example of shortening the interval between coils, FIG. 17 is an example of a target cooling curve, and FIG. 18 is a graph showing temperature deviation of the coils. 1...Water cooling nozzle, 2...Pinch roll, 3...
Laying head, 4... Steel wire rod, 5... Roller conveyor, 6... Lifting roller table, 6a... Terra,
7... Heat retention cover, 7a... Base, 7b... Top cover, 8... Blast cooling unit, 9... Transfer roller conveyor 10... Concentrating device, 11... Support column, 12...
Blast blower 113... Blast nozzle, 14... Atmosphere stirring fan, 15... Straightening plate, 16... Lifting device, 17... Heat storage plate, 18... Gas burner, 19...
・Drive device, 20...Electric heater (thermal compensation device), 2
1... Wire rod hook is a prevention plate, 22... Table lifting device, 23... Refrigerant spray is a nozzle, 24... Refrigerant circulation blower 125... Piping, 26... Header Pipe, 27...Hot air circulation blower-128...Piping, 2
9... Temperature controller, 30... Hot air discharge pipe, 31...
・Fan, 32... Hot air suction pipe, 34... Blower
135... Nozzle, 36... Burner, 37...
Heat storage plate, 38... Non-contact coil thermometer, 39...
Roller speed meter (pulse generator), 40...control unit, 41...blower 142...regulating valve, 43...
・Flow meter, 44... Thermometer, 45... Boundary plate, 46
...transport conveyor, 47...side shift device, 4
8...Heating device, 49...Cold air suction town 50...
・Adjustment valve, 51... Air volume adjustment valve, 52... Piping, 5
3...Gate valve, 54...Blower 155...Control valve, 56...Cooling device, 57...Piping, 58...
Conduit, 59... heating device, 80... cooling device.

Claims (1)

[Scope of Claims] 1. A method for cooling a wire rod substantially uniformly over its entire length following hot rolling, wherein the wire rod after hot rolling is placed on a conveyor while being formed into a thick coil; The thick coil is transferred by a conveyor while passing through an enclosed environment where the atmosphere is stirred, and during the transfer within this one surrounding environment, the temperature of the outer surface of the thick coil in a cross section perpendicular to the coil transfer direction is roughly measured. By simultaneously holding the layered coil uniformly and loosening it one or more times, the heat dissipation near the center of the thick layered parts on both sides of the thickened coil is promoted, and the temperature of each part of the ring forming the coil is reduced. A method for cooling a hot rolled wire rod, which is characterized by cooling while reducing deviation. 2 In a method of cooling a wire rod substantially uniformly over its entire length following hot rolling, the wire rod after hot rolling is placed on a conveyor while being formed into a thick coil, and the thick coil is placed on a conveyor. The outer surface temperature of the layered coil in the cross section perpendicular to the direction of coil transfer is approximately equal to -
At the same time, by loosening the thick-layered coil one or more times and spraying a refrigerant onto the loosened portion, heat dissipation near the center of the dense layered areas on both sides of the thick-layered coil is promoted, and the coil is A method for cooling a hot-rolled wire rod, characterized by cooling the ring while reducing the temperature deviation of each part of the ring. 3. A device for continuously cooling hot-rolled steel wire, which includes a conveyor for placing and transferring the steel wire as a thick-layered coil, a heat retention zone divided into one or more sections surrounding the transfer path of the thick-layered coil, and the an atmosphere stirring means for keeping the atmospheric temperature uniform within the heat zone; a means for applying loosening to the thick-layered coil in the heat retention zone one or more times; and a means for spraying a refrigerant onto the coil at the loosening position. 1. A cooling device for hot rolled wire, characterized in that it is comprised of: