JPS5931830A - Method and device for cooling metallic strip - Google Patents

Abstract

PURPOSE:To prevent the generation of shape defects in a metallic strip by cooling the metallic strip with cooling rolls which permit cooling of a gaseous heat medium sealed therein and evaporating at high temp. with heat transmission tubes for cooling provided in said rolls. CONSTITUTION:A metallic strip 1 is put on >=1 pieces of hollow cooling rolls 2 provided in a cooling zone in a heat treatment line and is brought into contact with the rolls 2, by which the strip is cooled. The gaseous heat medium 5 sealed in the rolls 2 is cooled and condensed on the outside surface of heat transmission tubes 12 for cooling and forms liquid drops 13, which fall onto the inside walls of the rolls 2 and stick thereon, then the medium is again gasified by the heat from the strip 1. The temp. difference between the temp. at which the contact of the strip 1 initiates and the temp. of the rolls 2 is maintained within a permissible limit by a method of controlling the gaseous pressure of the medium 5, etc. and the generation of the shape defects in the strip 1 is prevented according to the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in the cooling power of hot metal strips and devices thereof.

Conventionally, continuous annealing of ordinary steel strips has been mainly used for annealing -C and Q plates for tin plating. In this case, the strip temperature in the annealing furnace
As shown in the figure. In this case, the strip is cooled by the cryogenic cooling tube in slow cooling! l? 1 indirect cooling,
In addition, in the rapid cooling zone, a cooling method in which low-temperature reducing atmosphere gas is directly applied to the strip has been mainly adopted.

Recently, a technology has been developed to obtain cooled steel sheets with excellent drawability and workability by continuous annealing instead of the conventional bunch annealing method. Since the steel stock is high and costs can be reduced, there is a tendency for continuous annealing (Jiti) to be used more and more in the future. The temperature diagram of the strip in this case is shown in Figure 2.

The temperature diagrams in Figures 1 and 2 indicate that the strip should be quenched at a rate higher than the metallurgically required minimum cooling rate (19h is the quenching zone of 21Y1), and as much as possible
1) Cooling with old, cheap cost and equipment (f'l
For example, a rapid cooling zone shown in Figure 1 or a cooling zone shown in Figure 2 is required.In this case, it is difficult to obtain a high cooling rate by directly blowing low humidity gas as described above, 'The sound is also J+.

Therefore, a method of rapidly cooling the strip by bringing a so-called water-cooled roll, which circulates cooling water inside the roll, into contact with the strip was previously proposed and has been put into practical use. However, although this cooling of the strip by the water-cooled roll does not cause any particular problem in terms of rapid cooling, the drawback is that the strip of the cooling shield is likely to suffer from defects in shape such as wrinkles and wilting. The reason for this is that cold-rolled strips usually have some roughness (hainobi or nakanobi) after 01%iiJ, and because of this, there is insufficient contact with the part that is in good contact with the water-cooled roll and is rapidly cooled. This causes uneven cooling and thermal stress, which causes shape defects such as wrinkles and wilting.

As a result of research into the relationship between strip cooling methods and shape defects that occur in strips, the present inventors have previously found that
[Ijj chanting cooling method using rolls” (special; black bean paste 55
-9-7482, Japanese Patent Application No. 55-97483). The gist of these is that, for each strip temperature at the start of contact between the strip and the cooling roll, the temperature difference between the cooling roll temperature and the strip temperature at the start of contact with the liquid is as follows. By keeping the temperature within 1 historical difference, it is possible to suppress shape defects to a level that does not cause any practical problems.In the case of the water-cooled roll according to the method described in Section 4 above, the temperature of the cooling water flowing inside the water-cooled roll is Ha, ma
x.

100 C or less (generally 80 t:? or less), and if the measured tube temperature is ()), the temperature difference ΔT exceeds the above-mentioned tolerance limit, resulting in a defective shape.

The present invention was proposed for the purpose of eliminating the drawbacks of the above-mentioned proposed method, and the present invention is aimed at resolving the drawbacks of the above-mentioned proposed method. In the method of cooling by letting the material flow in contact with the material, a hollow roll filled with a heat carrier gas that evaporates at a high temperature is used as the cooling roll, and a cooling medium is allowed to flow inside. The present invention relates to a method for cooling a metal strip, which involves exchanging heat between the cooling heat blue and the heat carrier gas.

Further, the present invention provides a high-temperature metal strip 1-' running at a predetermined speed in a continuous metal strip processing line.
In the metal strip cooling method in which the J-shaped roller is brought into contact with the outer circumferential surface of the cooling roll, the cooling roll is made hollow, and a heat carrier gas that evaporates at high temperature is placed inside the hollow cooling roll. The present invention also relates to a metal strip cooling device characterized in that a cooling heat transfer tube through which a cooling medium flows is inserted into the heating medium gas.

The present invention will be specifically explained below with reference to FIG.

In FIG. 6, 1 is a metal strip to be cooled, 2 is a hollow cooling roll, and 3 is a roll bearing. 5 is a gaseous heat medium sealed inside the hollow cooling roll 2;
6 is a supply pipe for the gaseous heat medium 5, and 7 is a rotary joint for the supply pipe. 8 is a cooling medium population, 9 is a water seal, 110 is a cooling medium amount 1], 11 is an I surface of the water seal, and 12 is a cooling heat exchanger tube provided in the heat medium gas.゛Moto Genmei equipment-
VII is constructed as described above, and the method of the present invention is carried out as described below. That is, the metal strip 1 releases heat, )li! In the line, the hollow cooling roll 2 provided in the cooling zone or (i+) is rolled around and cooled by cooling from the contact surface with the cooling roll 2. , will be 1+. The gaseous heat medium 5 that has been transferred to the cooling roll 2 is cooled on the external surface of the cooling heat transfer tube 12, and is captured and condensed into droplets 16, which fall and drop into the cold droplet 2. Attach 7 to the inner wall of circle 1i175B, then from Strisozo 1? '6,',:
(Due to the heat transmitted through the 2 walls of Ironil 11), it evaporates into a gaseous state, but at this time it takes away more heat of evaporation than the rolls 11 and 1 river.

Since cold, ξ1 medium and 1~teζ plain water are used,
Cooling heat transfer/if 12's surface temperature can be maintained at 50 to 80 C at all times by flowing cooling water inside. As is well known, when a major change such as condensation or evaporation is involved, the heat growth coefficient is large, so there is an advantage that the camellia face bond can be small. Also, cooling roll 2
In the inner hollow part, the heat medium vapor 5 and /I11. (i-miya i
15, the cooling roll 2's lifetime iX° is reduced compared to the case where a liquid medium is sealed, and the shaft, load, 4I, and roll drive power are reduced, which is an advantage. 1 <, there is no need to stir the heat medium.

Furthermore, by controlling the gas pressure of the gaseous heating medium 5, the steam temperature of the gaseous heating medium 5 is controlled, thereby controlling the vorticity of the cold JBI roll 2, and adjusting the cooling rate. The gaseous heat medium 5 is evaporated with high crystallization (20 to 700), and 20
Suitable materials are those that can be condensed and liquefied at 0U or less and have good fluidity at C. For example, biphenyl (boiling point 254
:4-anchor degree 528C), Decerin (boiling point 185-195
C1 critical temperature 408-419C) etc. are used. Although not shown in No. 61.1, it is also possible to add fins to the cooling roll 12 to further improve heat conduction.

In short, the present invention provides a method for cooling a high-temperature metal strip running at a constant speed of H1 on a continuous processing line for IJ tubes by bringing it into contact with the outer peripheral surface of a cooling roll. As the cooling roll, a hollow roll in which part 21 is filled with a heating medium gas that evaporates at +W+ temperature is used, and a cooling heat exchanger tube in which a cooling and operating body is passed through and wetted, and a heat recording medium are used. According to the present invention, since the gist is a method for cooling an IJ tube (metals) characterized in that the gas and
The present invention has the practical effect of being able to overcome the drawbacks of the cooling method previously proposed by the present inventors.

In addition, Honzua Akira has a continuous processing line K for metal strips.
G is a high temperature metal string that runs at a predetermined speed.
In a metal slab cooling device that comes into contact with the outer circumferential surface of a cooling roll, the cooling roll is hollow, and a heat carrier gas that evaporates at 1 liter (I temperature) is sealed inside the hollow cooling roll. In addition, since the gist of the present invention is a cooling device for a metal strip, the device is characterized in that a cooling heat transfer tube through which a cooling medium flows is inserted into the heat transfer gas. According to this method, the above-mentioned cooling method can be implemented easily and reliably, which is a practical effect.

4 [commercial quantity 1'+i] jy explanation] Figure 1 is a diagram showing the temperature of the string in the annealing furnace and the force of the fitting, Figure 2 is the temperature diagram of the strip in continuous annealing equipment. FIG. 6, a diagram showing an example, is a schematic longitudinal sectional view of an example of the arrangement of the present invention.

In Figure 3, 1: metal IJ knob, 2: hollow cooling roll, 3
: Bearing, 5: Heat medium gas, 6: Heat medium gas common supply pipe, 7:
Rotating joint, 8: Cooling medium population, 9: Cooling medium water seal (Yu,
10: Cooling medium outlet, 11: Cooling medium water''1, 12
: Heat transfer for cooling 3;.

Claims (2)

[Claims] (1) Gold, (・In the continuous processing line of the strip, a high temperature metal strip running at a predetermined speed is brought into contact with the outer circumference +j:' of the cooling hole... ;11! In the cooling method, a hollow roll having a heating medium gas that evaporates at a high temperature inserted therein is used as the cooling roll, and a cooling heat transfer tube through which a cooling medium is circulated and the above-mentioned (Metals whose special punishment is to exchange heat with heat carrier gas) IJ tag cooling power f people. (2) A metal strip in which a high-temperature gold maple strip running at a predetermined speed in a metal strip processing line is brought into contact with the outer peripheral surface of a cooling roll.
+a'', the above cooling roll is made hollow, and the inside of the hollow cooling roll is filled with a heat carrier gas that evaporates at a temperature of i A cooling device for a metal strip, characterized in that it is formed by inserting a cooling roll through which the metal strip is circulated.