KR100527064B1 - Injection nozzle and Method for manufacturing strip wire using it - Google Patents

Abstract

The present invention relates to a spray nozzle for cooling a high temperature wire rod and a method for manufacturing a hard steel wire rod using the same. More specifically, the mechanical properties of the wire rod due to cooling can be made uniform because the speed and particle size range of the droplets ejected through the nozzle can be made uniform. The present invention relates to a spray nozzle capable of increasing physical properties and a method for producing a hard steel wire rod using the spray nozzle, wherein the spray nozzle of the present invention is for supplying air at a constant pressure and is in linear communication with the spray pipe (112). A first supply pipe 114 and a second supply pipe 116 vertically connected to the first supply pipe 114 and the injection pipe 112 to supply water at a predetermined pressure, and the spray nozzle In the method of manufacturing hard steel wire using the step of preparing the highlighting material of the billet at a certain weight%, the billet formed in the step according to the wire rod rolling process Cooling and cooling to a temperature of 800 ~ 850 ℃ before winding the wire, dropping and transporting the overlapping density of the wire rod after winding, and mixing air and water with a constant pneumatic and water pressure using a spray nozzle. Cooling the wire rod by spraying, adjusting the moving speed of the wire rod to 0.30 to 0.60 m / s, and adjusting and controlling the output of the blower to 30% from the bottom of the wire rod.

Description

Spray nozzle used to cool high temperature wire and method for manufacturing hard steel wire using it {Injection nozzle and Method for manufacturing strip wire using it}

The present invention relates to a spray nozzle for cooling a high temperature wire rod and a method for manufacturing a hard steel wire rod using the same. More specifically, the mechanical properties of the wire rod due to cooling can be made uniform because the speed and particle size range of the droplets ejected through the nozzle can be made uniform. The present invention relates to a spray nozzle capable of increasing physical properties and a method for manufacturing a hard steel wire using the same.

In the hot rolling process, the wire is transferred to a high temperature state, and a cooler is used to cool it. Referring to Fig. 1, the cooling process of the conventional wire rod is as follows. The wire rod transferred from the rolling mill 10 is moved to the winder 30 in a state where the temperature is lowered while passing through the water cooling device 20. In the winding machine 30, the moved wire rod 40 is dropped on the table roller 50 of the cooler (stallmore cooler) in the form of a concentric ring, and the dropped wire rod is placed on the table roller 50 in a stacked state. Is transferred. The transported hot wire 40 is cooled by the air blowing from the blower 60 installed in the lower portion of the table roller 50, the final wire product having the mechanical properties desired by the customer is produced through this cooling process.

In the forced cooling method by the blower 60, referring to FIG. 2, the rolled hot wire 40 passes through the winder 30 and falls in a coil ring form in a straight line to form a table roller 50. When it is transported in the state of), the wire rod is forcibly cooled by air while being in contact with low-temperature wind blowing from the blower 60 installed in the lower portion. In the blower 60, wind is generated from a propeller (not shown) by the rotational force of the blower motor 62, and a direction in which the blower 60 is supplied by the damper 64 mounted therein is changed. Stallmore sidewalls 66 are provided at both end portions of the table roller 50 to prevent the wire rod 40 from being separated during the transfer.

However, the following problem occurs in the forced cooling method as described above. That is, since the wire falling from the winder 30 is dropped in a non-concentric ring state, there is a relatively high overlap density between the rings and a low overlap density, and thus the cooling is not uniform, thus forced air cooling. There are many difficulties in reducing the cooling deviation even by the method. Therefore, there was a difficulty in producing wire rods with mechanical properties desired by customers.

In order to solve this problem, a cooling apparatus and a method using a cooling medium other than air have been developed. One of these is Direct Lead Patenting, a salt bath cooling facility that combines water and salt baths developed by Kimitsu Steel Mill in Nippon Steel Corporation. By artificially controlling the wire products produced in the winding machine to pass through the salt bath, a product of about 15% higher tensile strength, which is a mechanical property, was produced than the wire products produced by the conventional Stelmore cooling method.

In addition, in Sumitomo Steel Mill, the company developed a new wire rod cooling system called Easy Drawing Conveyor, which uses boiling water instead of air, to commercialize products with improved mechanical properties.

In addition, in case of TOA Steel, the cooling medium is introduced with a spray method of mixing water and air in the air, thereby cooling the wire product through coaxial collision of water and air and atomization of particles. Was performed. As a result, commercialization of products with improved mechanical properties of wire rod products has been carried out since 1988.

The spray cooling has a cooling mechanism that cools and atomizes the liquid droplets obtained from the liquid column by colliding and pulverizing the liquid column injected through the nozzle with high-speed air kinetic energy. It is possible to develop an independent cooling system utilizing the characteristics of the spray nozzle without significantly changing the mower cooler.

However, the final wire product with uniform material variation can be produced only by controlling the change of the injection pressure of air and water through the spray nozzle and the uniform particle velocity and particle input, and the velocity and particle diameter of the droplet particles ejected through the nozzle. If the range is not uniform, there is a disadvantage that the quality temperature is caused by the deviation of the cooling temperature and the tensile strength, which is a mechanical property of the material.

3 is a cross-sectional view showing a structure of a spray nozzle 90 that is conventionally used, wherein a water supply pipe 94 for supplying water is formed in the center, and an air supply pipe 92 for supplying air along its periphery is formed. Formed. The internally mixed two-fluid spray nozzle 90 has a characteristic of generating fine droplets by colliding a gas (air) having a large velocity component (kinetic energy) with a liquid column, which is a spray liquid, in the spray nozzle 90. In the discharge part (the ends of the water supply pipe 94 and the air supply pipe 92), the velocity and particle size of the droplets are not uniform to maintain uniform cooling in the process of being released into the atmosphere by the collision of the two fluids. Occurred. It has almost no gap between the two fluid impact points and the point where it is ejected into the atmosphere, so that the mass flow rate of the particles and the particle size of the liquid column are uniformly crushed when the liquid collision occurs due to high-speed air energy. It is caused by not being able to. Therefore, many trials and errors and repeated experiments have to be carried out in order to set up the optimum spraying conditions.

The present invention is to solve the above problems, an object of the present invention is used to cool the hot wire that can evenly spray droplets having a fine and uniform particle diameter in the collision of water and air injected at high speed To provide a spray nozzle.

Another object of the present invention is to provide a method for producing a hard steel wire which can produce a wire rod having improved mechanical properties without changing the structure of a conventional air cooling device or a spray device by using a spray nozzle having an improved spray uniformity.

Referring to the present invention for achieving the above object is as follows.

The spray nozzle of the present invention is for supplying air at a constant pressure, the first supply pipe which is in linear communication with the injection pipe, and for supplying water at a constant pressure, and is perpendicular to the first supply pipe and the injection pipe. Consists of a second supply pipe connected, the method for producing hard steel wire using the spray nozzle, the step of forming the highlighted material of the billet to a certain weight%, the billet formed in the step according to the wire rolling process winding the wire rod Cooling to a temperature of 800 ~ 850 ℃ before, dropping and transporting to adjust the overlap density of the wire rod after winding, and by spraying a mixture of air and water at a constant pneumatic and water pressure using a spray nozzle Cooling, adjusting the moving speed of the wire rod to 0.30 ~ 0.60m / s, and adjusting the output of the blower to 30% from the lower part of the wire rod. It includes the steps:

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4 is a schematic configuration diagram of a cooling device 100 having a spray nozzle 110 according to the present invention. As shown, the spray nozzle 110 is installed at a predetermined distance from the upper side of the table roller 50 to which the wire rod 40 is transferred. Although only one spray nozzle 110 is shown in the figure, three spray nozzles are actually provided with nine spray nozzles in three rows to simultaneously perform a spray function.

The spray nozzle 110 is connected to a pipe for supplying water and air, and each pipe is supplied with water and air at a constant pressure. The structure of such a cooling device is essentially similar to a device using a conventional spray nozzle. However, in the present invention, water and air pressure are changed to optimize the spraying characteristics of the spray nozzle 110. As the wire 40 is transported on the table roller, the water is injected through the spray nozzle 110 and the blower 60 installed at the lower portion of the table roller is operated at a constant efficiency to supply air for cooling. The blower 60 functions not only to cool the air but also to distribute the molecules of the water sprayed evenly. In order to maintain the optimum cooling conditions, the air and water pressure, the feed rate of the wire rod 40 of the table roller, the cooling temperature before winding, etc. are first set, and these values can be obtained through repeated experiments. . 1 and 4, the manufacturing method of the present invention will be described later.

Detailed structure of the spray nozzle 110 according to the present invention will be described with reference to FIGS. 5 and 6a and 6b.

5 is a cross-sectional view of an embodiment of the spray nozzle 110 of the present invention, for supplying air at a constant pressure, and is connected in a straight line by a pipe and a spray pipe 112 to which water is directly sprayed. The first supply pipe 114 and the second supply pipe 116 for supplying water at a constant pressure are connected with the pipe perpendicularly to the first supply pipe 114 and the injection pipe 112.

The injection pipe 112 is for spraying the spray generated by the collision of air and water, the spray hole 112a is formed on the surface. In addition, the first supply pipe 114 is for supplying air at a constant pressure (Pa), the second supply pipe 116 is for supplying water at a constant pressure (Pw). Whereas the first supply pipe 114 is connected to the injection pipe 112 in a straight line through a pipe, the second supply pipe 116 for supplying water is the first supply pipe 114 and the initial supply portion Maintain parallelism and bend vertically. The bent end is coupled to communicate with an intermediate portion of the pipe connecting the injection pipe 112 and the first supply pipe 114.

The spray nozzle 110 according to the present invention causes the collision between two fluids, air and water, from the point where the collision occurs, so that the primary atomized droplets are nozzles along the pipe set about 40 to 60 mm (preferably about 50 mm). Through the tunnel, there is a secondary secondary collision due to surface tension and inertia between the droplets, and the particle diameters are uniformly ejected into the atmosphere, thereby maintaining uniform droplet velocity and particle size according to the air and water pressure changes. You can do it.

Referring again to Figure 5 describes the relationship between the pressure of water and air as follows. Where Pa is the pressure for supplying air, Pw is the pressure for supplying water, and Px is the pressure at the point where air and water collide. In addition, ΔPa is a value obtained by subtracting the pressure change (Px) at the point where air and water collide with each other from the pressure of the incoming air (Pa), (△ Pa = Pa-Px; Pa = constant), and ΔPw is the It is the value obtained by subtracting the pressure change at the point where air and water collide in pressure (ΔPw = Pw-Px; Pw = constant). Using this pressure value, the spraying effect of the spray nozzle 110 of the present invention will be described.

Assuming that the pressure of air in the incoming air and water is constant, △ Pa and Px have an inverse relationship, so if the pressure at the point of collision is increased, the pressure change at the point of collision of air and water at the pressure of incoming air is This increases the mass flow rate of the water and increases the particle size of the overall droplets, but the particle velocity is relatively low.

On the contrary, if the pressure at the point where the collision occurs is reduced, the pressure change at the point where the collision between air and water occurs at the pressure of the incoming air becomes smaller, and thus the mass flow rate of the water becomes smaller, resulting in a smaller particle size and an overall drop size. Speed becomes relatively large. This correlation can be seen from the above equation.

In addition, when the water pressure, which is the mass flow rate of the water, is gradually increased to increase the diameter of the particles, the particle size and the particle size distribution range of the particles become large, resulting in contact between the hot material and the atomized spray particles The cooling effect of the boiling (boiling) effect is gradually reduced so that the overall cooling capacity is relatively lower than when the diameter of the particles.

On the other hand, if the mass flow rate of the water is reduced and the air pressure is increased, the particle size of the particles becomes relatively smaller than the increase of the water pressure, resulting in an extremely fine atomization phenomenon. The effect of becoming slightly more uniform than the mass flow rate of water may occur, but the cooling capacity in this case may be lower than that of the mass of water.

This is because, when the particle size of the particles is excessively atomized, evaporation proceeds before the droplets contact the hot wire surface, and the cooling effect may be significantly reduced.

In order to solve this problem, proper spraying conditions, particle velocity, and particle size selection are important factors through continuous and repeated experiments. In conclusion, when the cooling of the hot wire rod product proceeds, the large particle size of the droplets does not necessarily cool well, and the small particle size does not mean that the cooling is not performed. In the case of surface contact cooling by spray particles of hot wire, liquid film generation by boiling phenomenon is essential, and the cooling effect due to the uniform thickness formation of the liquid film may be changed. For this purpose, an optimal embodiment of the manufacturing method according to the optimum state using the spray nozzle 110 of the present invention will be described later.

6a and 6b show the appearance of the spray nozzle 110 of the present invention, it can be clearly seen the arrangement of the injection pipe 112, the first supply pipe 114 and the second supply pipe 116. In particular, looking at the front state of the injection pipe 112, the spray hole (112a) is formed in an elliptical shape. This is to control the temperature variation for each width part caused by overlapping density difference of wire products by inducing the total mass flow value of water during spraying into elliptical spraying area. The spray hole (112a) has a length of 10mm long axis, 4mm short axis, the dimension (A) of the injection pipe 112 is 40mm, the body formed by the first supply pipe 114 and the second supply pipe 116. It is preferable that the dimension B of becomes 75 mm.

It describes a method for producing a hard steel wire using the spray nozzle 110 of the present invention having the configuration as described above.

FIG. 10 is a flowchart illustrating a manufacturing method according to the present invention. First, a billet is manufactured by continuously casting a high carbon steel hard wire having a certain chemical composition. This billet is Japanese Industrial Standard JIS SWRH72B (corresponding to Korean Industrial Standard KS D 3559) which is widely used in wire rod manufacturing.The chemical composition is C: 0.60 ~ 0.75% by weight, Si: 0.15 ~ 0.30% by weight, Mn: 0.60 ~ 0.90 % By weight, P: 0.04% by weight, S: 0.60 to 0.05, and the rest is composed of Fe and unavoidable impurities. The billet is hot rolled to a diameter of 5.5 mm∮ and cooled to a cooling start temperature range of 800 to 850 ° C.

The billet continuously cast as described above is rolled through the usual hot rolling process, and the temperature of the wire is cooled to 800 to 850 ° C. before winding to supply it to the winding machine.

After winding the linear wire rod cooled as above through a winding machine in the form of concentric circles, forced cooling is performed by spray cooling to 500 ° C. on the cooling table under the cooling conditions shown in the following table. At this time, in order to increase the efficiency of cooling, it is desirable to minimize the overlapping density of the wire rod coils.

Referring to FIG. 4, the spray nozzle 110 according to the present invention is sprayed by installing a total of nine in three rows in each of three sides at both sides and a central portion from the surface of the wire 40 to an upper side of about 300 to 500 mm. The diameter of the spray particles to be sprayed is optimized to have a size of 10 ~ 20㎛, the pressure of the water and air to be sprayed and the installation height of the spray nozzle can be adjusted to achieve this. The feed rate was set to 0.3 m / s before spraying.

When the height of spray nozzle is adjusted to 500mm or more in actual application, the particle diameter becomes 20㎛ or more, and it does not help to improve the cooling performance by forming excessive liquid film when cooling with high temperature material. This is because, when adjusted to, the diameter is distributed to 10 μm or less due to an increase in the particle velocity, and vaporized before contact with a high temperature material, thereby significantly lowering the cooling capacity.

By spraying through the spray nozzle 110 as described above to perform spray cooling and at the same time set the feed rate of the wire coil to 0.3 ~ 0.4m / s. In addition, the blower was set to about 30% of the maximum output to distribute the spray particles evenly on the upper and lower surfaces of the high temperature wire.

The air and water pressures of the spray nozzles were 1.0 x 1.5 kgf / cm ² , 1.5 x 2.0kgf / cm ² , 2.0 x 2.5kgf / cm ² , 2.5 to obtain the particle size of the droplets to increase the cooling efficiency of the wire rod. x 3.kgf / cm ² , 3.0 x 3.5kgf / cm ² , 3.5 x 4.kgf / cm ^2, 4.0 x 4.5kgf / cm ² , 4.5 x 5.0kgf / cm ² . This is uniformly distributed between the range of the optimum particle diameter in the installation conditions of the spray nozzle 110 is a value that increases the efficiency when cooling with a high temperature material.

When the air and water pressure is set to 5.0 x 5.5 kgf / cm ² or more, the mass flow rate of water decreases, and thus the particle diameter is distributed to 10 μm or less, resulting in a decrease in cooling efficiency, and 0.5 x 1.0 kgf / cm ² or less. This is because the air pressure is low in this case, and the kinetic energy of the air which causes atomization of the liquid column by the water pressure is extremely low.

The results using the spray nozzle of the present invention and the forced cooling method using a conventional blower are shown in Table 1 below. Installation conditions of the spray nozzle is the same as that described above, a state where the air and the water injection pressure is set as each of ^{1.0kgf / cm 2, 1.5kgf / cm} 2.

In the case of spray cooling 1,2,3 coiling, it can be seen that the variation in tensile strength is comparable to that of the conventional 4,5,6 coiling using the Stelmore cooler as a comparative material. However, it can be seen that the tensile strength value for improving the strength is improved by 15% on average.

Particularly, when spray cooling is performed on high temperature wire rods, the speed of the table rollers in the Stellamore cooling section is lowered to 0.3 ~ 0.4m / sec, which is 40% of the conventional level, so that spray cooling for each wire coil portion can proceed sufficiently. This results in uniform cooling throughout the coil length.

7 and 8 are graphs showing the velocity and particle size distribution of droplets under certain conditions. FIG. 7 shows the velocity distribution of the droplets in the condition of spraying air and water at 1.0A x 1.5W and the spray height is 300mm, and FIG. 8 shows that the spraying condition is also 1.0A x 1.5W and the particle size distribution of the droplets is It shows that it is 10.11-20.04 micrometers.

In Fig. 9, the graph shows the distribution of tensile strength by the method of the present invention and tensile strength by the conventional method under the above conditions. As shown, it can be seen that the tensile strength of the wire rod by the spray (Mist) of the present invention is increased as 1.65: 1.54 as a result of comparing the average value.

Thus, according to the present invention, it is possible to evenly spray droplets having a fine and uniform particle diameter in the collision of water and air injected at high speed, and by using a spray nozzle having an improved spray uniformity, conventional air cooling apparatus or spray There is an effect that can produce a wire rod with improved mechanical properties without changing the structure of the device.

1 is a configuration diagram of a forced air blowing facility for cooling the hot wire used in the prior art,

2 is a structural diagram of a blower for cooling the wire rod,

Figure 3 is a side cross-sectional view showing a structure of a conventional spray nozzle,

Figure 4 is a schematic view of the operating state of the spray nozzle according to the present invention,

5 is a structural cross-sectional view of the spray nozzle according to the present invention;

Figure 6a is a plan view showing the appearance of the spray nozzle of the present invention,

6B is a front view of the injection pipe of FIG. 6A,

7 is a graph showing the velocity distribution of droplets according to the present invention;

8 is a graph showing a particle size distribution of droplets according to the present invention;

9 is a graph showing a wire rod tensile strength distribution according to the present invention,

10 is a flowchart illustrating a method for manufacturing hard steel wire of the present invention.

※ Explanation of symbols about main part of drawing ※

10: wire rod mill 20: water cooling device

30: winding machine 40: wire rod

50: table roller 60: blower

62: blower motor 64: damper

66: sidewall 70: accumulator

90: spray nozzle 92: air supply pipe

94: water supply pipe 96: spray

100: spray cooling apparatus 110: spray nozzle

112: injection pipe 112a: spray hole

114: first supply pipe 116: second supply pipe

Claims (5)

In the spray nozzle for injecting air and water by mixing at a constant pressure, The first supply pipe 114 for supplying air at a constant pressure, and the first supply pipe 114 connected in a straight line by the injection pipe 112 and the pipe, and for supplying water at a constant pressure, the first supply pipe 114 and the powder It is composed of a second supply pipe 116 is connected to the pipe perpendicular to the pipe 112 and the connection portion of the pipe constituting the first supply pipe 114 and the second supply pipe 116 of the injection pipe 112 Spray nozzle, characterized in that the distance to the spray hole (112a) is in the range of 40 ~ 60mm. The method of claim 1, Spray nozzle, characterized in that the spray hole (112a) of the spray nozzle is composed of an oval. In the method for producing a hard steel wire using the spray nozzle of claim 1, The highlighting material of the billet is C: 0.60 to 0.75% by weight, Si: 0.15 to 0.30% by weight, Mn: 0.60 to 0.90% by weight, P: 0.04% by weight, S: 0.60 to 0.05, and the rest is composed of Fe and unavoidable impurities And cooling the billet formed in the step according to the wire rolling process and cooling to a temperature of 800 to 850 ° C. before winding the wire, and dropping and transferring the wire density to adjust the overlap density of the wire rod after winding. Cooling the wire rod by mixing and spraying air and water with a constant pneumatic and water pressure using a nozzle, adjusting the moving speed of the wire rod to 0.3 to 0.4 m / s, and outputting the blower from the bottom of the wire coil. Hardwood wire manufacturing method comprising the step of driving to adjust to 30%. The method of claim 3, The pressure of air and water supplied from the spray nozzle is 1.0 x 1.5 kgf / cm ² , 1.5 x 2.0 kgf / cm ² , 2.0 x 2.5 kgf / cm ² , 2.5 x 3.kgf / cm ² , 3.0 x 3.5kgf / cm ² , 3.5 x 4.kgf / cm ^2, 4.0 x 4.5kgf / cm ² , 4.5 x 5.0kgf / cm ^{2 It} is variable steel rod manufacturing method characterized in that the adjustable. The method of claim 3, Hard steel wire manufacturing method, characterized in that the separation distance between the spray nozzle and the wire is in the range of 300 ~ 500mm.