JPS59226122A - Immersion cooling pipe for wire rod and steel bar - Google Patents

Abstract

PURPOSE:To provide a titled cooling pipe which improves cooling capacity by setting the annular nozzles which are provided at both ends of a cylindrical body and ejects cooling water toward the inside of the cylindrical body at adequate sectional areas according to the flow rate of the cooling water and the bore of the annular nozzles. CONSTITUTION:A cooling pipe 1 is provided with inlet and outlet guide parts 5, 6 at both ends of a horizontally disposed cylindrical body as well as jackets 3 fitted onto the outside circumference thereof and a draining port 7, etc. on the bottom surface in the central part, ejects the cooling water introduced from cooling water supplying pipes 4 through said jackets 3 toward the inside of the body 2 from annular nozzles 8 provided concentrically with the body 2 and cools a wire rod body 9 such as a wire rod, steel bar or the like traveling through the axial center part of the body 2 while filling the cooling water in the body 2. The total Amm.2 of the sectional areas of the slits of said nozzles 8 of such cooling pipe is so set as to satisfy 40.Q<=A<=1,200.Q/D<1/2> (where D; the bore of the annular nozzle, mm., Q; the flow rate of the cooling water, m<3>/hr).

Description

[Detailed description of the invention] The present invention relates to an immersion cooling pipe for wire rods and steel bars.

As is well known, wire rods, steel bars, and other wire rods manufactured in one step during hot rolling are processed in a cooling zone installed after the finishing mill row in order to control mechanical properties and suppress scale formation. , the high temperature immediately after hot rolling is cooled down to a predetermined temperature. In such cooling zones, water is usually used as the cooling medium. For this water cooling,
It is important to uniformly cool the wire around the wire, in the longitudinal direction and in the cross-sectional direction, and to achieve high cooling performance. Improving the cooling capacity has the advantage that the flow rate of cooling water required to obtain a predetermined temperature drop can be reduced, so that the pump power can be reduced.

In addition, in continuous hot rolling, cooling water is supplied to the rolled material in an inter-stand cooling zone, such as between an intermediate rolling mill row and a finishing rolling mill row, and then the rolling material is rolled again by the finishing rolling mill row.
E extension is being carried out. This controlled rolling is a hot rolling method in which heating temperature, rolling temperature, rolling reduction rate, etc. are fully controlled, and the purpose is to make the crystal grains fine and uniform in the wire material and improve the mechanical properties. In this state, it is possible to produce a wire material having the same structure and mechanical properties as the normalized material. In order to realize the full temperature pattern of controlled rolling, the inter-stand cooling zone must have as high a cooling capacity (heat transfer coefficient) as possible and must have a wide control range.

Conventionally, various types of cooling pipes have been used in cooling zones in the various rolling processes described above.

For example, from the slits arranged at regular intervals in the circumferential direction of the inner tube near both ends of the inner tube of the cooling tube, the rolled material is There is a spray type that sprays cooling water in the direction of travel.

This one-spray type has the disadvantage that the cooling capacity is high in the areas where the high aqua regia is directly in contact with the rolled material, but low in other areas, which is compared to the length of the cooling zone, the flow rate of the cooling water, and the pump power. Therefore, the cooling efficiency is low.

Therefore, the applicant of the present application provided an immersion type cooling pipe with excellent cooling performance in KOKOKU No. 57-14965.

According to this, the cooling water is jetted out from annular nozzles provided at both ends of the cooling pipe in opposite directions to form a water film that covers the opening of the cooling pipe, and at the same time, Cooling water was supplied into the pipe, and the inside of the pipe was filled with cooling water. According to this immersion type cooling pipe, the high-temperature wire material running along the axis of the cooling pipe is immersed in the cooling water filling the pipe, and the contact time with the cooling water is long. Extremely high cooling performance can be obtained by providing uniform cooling. This immersion type cooling pipe was developed with the main focus on how to fill the pipe with cooling water.

However, subsequent research has revealed that the cooling capacity of immersion-type cooling pipes is greatly affected by the state of the flow of cooling water within the pipes. The flow condition is affected by the amount of cooling water supplied, the pressure of the cooling water supply (nozzle pressure), and the distribution of cooling water pressure in the circumferential direction of the annular nozzle in the cooling water supply, and these ultimately affect the disconnection of the annular nozzle. It turns out that it depends on the area.

Therefore, based on the above research, an object of the present invention is to provide an immersion cooling pipe for wire rods and steel bars whose cooling capacity is improved by making the slit cross-sectional area of the annular nozzle μ appropriate. shall be.

Therefore, the feature is that the cooling water is spouted inward from the annular nozzle μ provided at both ends of the cylinder having a horizontal axis and concentrically with the axis to cool the inside of the cylinder. In a cooling pipe filled with water and immersed to cool a wire rod or steel bar that runs through the axial center of the cylinder, the sum (-) of the slit cross-sectional areas of the annular nozzles at both ends is 40.Q≦ A≦1,200・Q/σ However, D: Inner diameter of the annular nozzle (w) Q: Cooling water flow rate (go/hr).

Hereinafter, embodiments of the present invention will be described in detail based on all the drawings.

The immersion type cooling pipe (1) according to the present invention shown in FIG.
A cylindrical body (2) arranged horizontally, a jacket (3) fitted around the outer peripheral surface of both ends of the cylindrical body (2), and the jacket t
- The cooling water supply pipe (4) connected to (31) and the inlet guide part (5) extending concentrically to both end surfaces of the cylinder (2).
) and an exit guide part (6). Entrance guide part (5
) has a tapered inner surface.

A drain port (7) is provided on the lower surface of the axially central portion of the cylinder (2).
) has been established. The parts located inside the jacket (3) at both ends of the cylindrical body (2), the entrance guide part (5) and the exit guide part (6) are respectively connected to the jacket (
3) An annular nozzle 1v that communicates between the inside and the inside of the cylinder (2)
(81) This nozzle (8) is concentric with the axis of the cylinder and opens inward of the cylinder (2), and the orientation angle with respect to the axis of the cylinder (2) is shown in Figure 1. 01 on the entrance side,
The exit side sound θ is set so that 30″≦(θ1, θ,)≦60″. In addition, the annular nozzle IV (inner diameter 0 of 81 is approximately 60w5~120m, total length of cylinder body (2))
The amount of water is approximately 7 to 1,000 m, and the amount of water supplied per cooling pipe is 15 to 5 oz/hr.

The slit width (1) of the annular nozzle (8) is set so that the total slit cross-sectional area (-) satisfies the following: 40.Q≦A≦1.200.Q/σ.

Next, the reason why the total slit cross-sectional area (~) is set as described above will be explained.

Using the immersion type cooling pipe (1), we varied the nozzle orientation angle (, slit width (1), and cooling water supply amount 0) to create a cooling pipe (1) that is thought to affect the cooling performance. ) We observed the flow of cooling water inside.

As a result, as a general trend, as the number of cooling water supply parts θ) increases, and even for the same amount of cooling water Q, the slit width (
1) becomes smaller, the jetting speed of the cooling water from the nozzle )v(81 increases, and accordingly, more air is sucked in from the inlet and outlet sides of the cooling pipe (1). 1) The amount of bubbles generated increases.

Also, if the slit width (1) is the same, the nozzle orientation angle C
) was found to be more likely to generate bubbles.

The generation of bubbles causes a heat insulating layer to exist between the wire material such as a wire rod or steel bar and the cooling water, which is undesirable because of the removal of a boiling film from the cooling surface, resulting in a decrease in cooling performance.

The degree of bubble generation is considered to depend on the jetting speed of the cooling water, that is, the level of pressure within the cooling water supply section (inside the jacket (3)).

Therefore, using a cooling pipe (1) with a nozzle orientation angle (0) of 60≦θ≦60°, a pressure gauge was attached to the cooling water supply part (3), and each cooling condition (cooling water supply amount @, nozzle orientation Cooling water supply section (3) at angle (of, slit width (t))
The pressure was measured and the bubble formation status at that time was investigated.

As a result, when the pressure head Φ) in the cooling water supply section (3) becomes approximately 4 m or more, in any cooling condition, there is a It was found that the generation of bubbles due to air suction becomes considerably large.

Therefore, in this type of immersion type cooling pipe (1), in order to completely prevent the cooling capacity from decreasing due to the formation of air bubbles, the pressure of the cooling water supply part (3) must be 664 m (0.4 atmospheres or less)...・・・・・・・・・・・・
・・・・・・・・・・・・・・・■ It is desirable.

By the way, in the cooling pipe (1), the relationship between the cooling water supply amount (Qm/h), the slit cross-sectional area of the nozzle (AIF/), and the pressure (hfn) of the cooling water supply part (3) is an incomplete equation. expressed.

Q = Q! A item ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・■C3;
Nozzle coefficient 60.80 g; From gravitational acceleration h=C・(S)2 ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・■Δ 0 = −r−−7,97x 10−”0.2g From the above formulas ■ and ■, the nozzle is 664 m/ L' (8)
The slit cross-sectional area (Ari range is = sq, 4Q = 40Q...■).

For uniform cooling, it is preferable that the fluctuation of the flow rate in each part of the circumferential direction of the annular nozzle is as small as possible.

However, in the annular nozzle A/(8), a pressure difference occurs between the top and bottom ends due to the height difference, and if the pressure of the cooling water supply section (3) at the top is 'k(h), then the pressure at the bottom end is pressure d
(h+nX1o). As mentioned above, in the present invention, since h≦4ffi and the pressure is low, the pressure difference due to the zero inner diameter of the annular nozzle A/(81) cannot be ignored.

Since it is desirable that the fluctuation in flow rate due to this pressure difference be at least about 1096 or less, the equation 0 is satisfied.

Therefore, it is formula 0) h≧4.26 X 10 D (4,26X 1O-
4D atmospheric pressure)...■.

Therefore, from formula 0 and formula 0, the unit is A (-), Q Cm'/hr)
, D (fi).

Therefore, according to equations ① and 0, the optimal slit cross-sectional area (gradient) is 40・Q≦A≦1200・Q/F.

Figure 2 is a graphical representation of the above relationship, and D
The slit cross-sectional area (the chrysanthemum range is shown) for the predetermined cooling water flow rate Q for -60 vn, 90 ro, and 120 baits. In each case, the value (A) within the diagonal line in the graph may be adopted.

According to the cooling pipe (1) according to the present invention, the predetermined pressure (
h) The cooling water is supplied to the jacket (3) through the supply pipe (4).
The cooling water is supplied from the annular nozzle (8) to the cylinder (
2) It is ejected inward. This nozzle A/(81
The jet flow from the cylinder (21) flows toward the center of the cylinder (21), collides at the center, and tries to fill the cylinder (21).At this time, some of the cooling water flows through the drain port (7). However, the remaining part of the supplied cooling water is discharged from openings at both ends of the cylinder (2), filling these openings with water flow.

As a result, after the start of water supply, the inside of the VC body (2) is quickly filled with cooling water and reaches an immersion state.

Therefore, in the immersed state, the entrance guide part (5)
By running the wire material (9), which is a flat wire material or a steel bar, through the axial center of the cylinder (2), the wire material (9) is cooled while being immersed in cooling water. Ru.

In this immersion cooling, the slit cross-sectional area (A) of the nozzle (8) is set to 40Q≦A≦1200Q//P, so the amount of bubbles generated in the cooling pipe (1) is small, and the annular nozzle Since a uniform flow rate of cooling water can be obtained from each part in the circumferential direction into the cooling pipe, cooling performance and uniformity of cooling can be improved.

Table IVC, in the immersion type cooling pipe (1) of this h
Table 1 shows a comparison of the cooling capacity when = 0.6rn and 5ffl. Comparison of cooling capacity in immersion type cooling pipes As is clear from Table 1 (b = 0.6 m, 11 = = 5 - J: the cooling capacity is excellent. In other words, h = 0.6) The material satisfies 40·Q≦Ai, and is found to provide excellent cooling performance704.

In addition, in the cooling pipe (1), since the drain port (7) is provided on the side surface of the cylindrical body (2), an effective replacement rate of cooling water (cooling water supply) in the cooling pipe (1) is provided. Amount Qc of cooling water discharged from the cooling pipe center drain port (7) relative to the amount 0
O ratio; QO/Q > e could be increased.

In general, for immersion type cooling pipes, if the effective displacement rate of this cooling water is low, it means that some of the cooling water remains in the cooling pipe, and the pooling of cooling water causes the average As the water temperature rises, the cooling capacity for the stationary part of the rolled material becomes lower than the cooling capacity for the leading end of the rolled material. That is,
There is a difference in cooling water temperature between the tip of the wire material and the stationary part.
This results in non-uniform cooling in the longitudinal direction.

In contrast, cooling water is supplied into the pipe from the center of the cooling pipe,
If the cooling pipe has a conventional structure that drains water from both ends of the cooling pipe (as described in British Publication No. 57-14965), if the length of the cooling pipe is short, the cooling water will be replaced well. This is not a problem, but if the length of the cooling pipe becomes long (in this example, the inner diameter of the cylinder (2) is about 60 m to 120 m, and the length is about 700 m to 1,000 m), some of the cooling water will leak into the pipe. As a result, the cooling water replacement rate decreased, which was not preferable.

In this embodiment, the drain port (7
), the effective replacement rate of cooling water was increased, and this problem of uneven cooling was solved.

Note that the present invention is not limited to the above embodiments,
As shown in Fig. 6, the cooling pipe (1) is also applied to the cooling pipe (1) in which exhaust holes are provided along the longitudinal direction on the upper side of the cylindrical body (2). tube(
1) Air bubbles generated inside can be effectively discharged, further improving cooling performance.

According to the present invention, since 40.Q≦A≦1200Q/i, the jetting speed of the cooling water from the annular nozzle is small, and the generation of bubbles is prevented to improve the cooling capacity, and the cooling pipe Since the pressure in the cooling water supply section (the pressure at the nozzle section) can also be small, it is possible to significantly reduce the power cost of the cooling water supply pump.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a cooling pipe employing the present invention, and Fig. 2 is a 40・Q≦A≦ for the supply water amount of 0 and the annular nozzle diameter (maximum).
A graph showing the relationship of 12ooQ/Jp and FIG. 3 are cross-sectional views showing another embodiment according to the present invention. (1)...Cooling pipe, (2)...Cylinder, (3)...
Jacket (cooling water supply section), (81... annular nozzle. Patent applicant: Kobe Steel, Ltd. Procedural Amendment (Spontaneous, August 311, 1982) 1. Display of 11 1981 Patent Application No. 1 (l O032shi3
2. Name of the invention, immersion cooling pipe for steel bars 3, relationship with Nagisa 1, which performs IF 1 seal of notification (sleeve ll-1 order II publication) 7
, Correction details Ill Mei II F, msNth row zs gtv r
(Qm3/h)” is corrected to r (Qm”/hr)J 〇(2) Same, page ro, line 13, “A knee Q, 10°” 3600 J Seven of them are 1 Italy: Correct as Aku-・Q--J.h 3600

Claims (1)

[Claims] 1. Cooling water is jetted toward the inside of the cylinder from annular nozzles provided at both ends of the body having a horizontal axis and concentric with the axis, so that the inside of the cylinder is completely filled with cooling water. In the cooling pipe for immersion cooling the wire or rod m running through the axial center of the cylinder, the total A(-) of the cross-sectional areas of the annular nozzles μ at both ends is 40·Q≦ A immersion cooling pipe for wire rods and steel bars, characterized in that A≦1,200·Q/, /T, D: inner diameter of annular nozzle (m) Q: cooling water flow rate (g/hr).