JPH08176884A - Method for quenching tin plated steel strip and device therefor - Google Patents

Abstract

PURPOSE: To execute uniform quenching in the transverse direction of a steel strip and to effectively prevent the generation of quench stains by eliminating the 'C camber' arising at the steel strip right after introduction into cooling water in a method for quenching the tin plated steel strip. CONSTITUTION: This method is provided with support rolls 6, 7 in series between a conductor roll 3 installed in the lower part in a quenching tank 2 and a cooling water spraying device 5 installed right under the water surface of cooling water 21. The support roll 6 functions to position the tin plated steel strip S along the pass line extending perpendicularly below from a reflow furnace 1. The support roll 7 functions to push the tin plated steel strip S to the inner side. The occurrence of the 'C camber' is entirely eliminated according to the pushing in amt. of the support roll 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quenching method for tin-plated steel strip and an apparatus therefor, and more particularly to a tin-plated steel sheet from which quench stain is prevented.

[0002]

2. Description of the Related Art Generally, in the case of a tin-plated steel sheet, in order to give the surface a luster, a reflow treatment for heating the tin-plated steel strip to melt the tin on the surface and a re-flowed steel strip are performed. The quenching process of rapid cooling is continuously performed. However, by such a treatment, a dirty pattern (quench stain) is generated on the plated surface as if the dirty water had adhered to the plated surface and dried, and the commercial value thereof is significantly impaired.

As a conventional example for preventing such quench stain, for example, JP-A-51-12693.
Some are described in Japanese Patent No. 4 publication. In this example, just before the reflowed tin-plated steel strip enters the cooling water of the quench tank, a large amount of cooling liquid is passed through the slit-shaped spray nozzle provided above the water surface of the quench tank to the strip. The cooling liquid is sprayed uniformly in the entire direction, and if necessary, a cooling liquid is sprayed to the steel strip from a spray nozzle provided below the water surface in the quench tank. As a result, the position where the steel strip first comes into contact with the cooling water is kept the same in the width direction, and the pressure and water amount of the cooling liquid at each point in the width direction of the steel strip are kept uniform, so A method for uniform cooling has been proposed.

[0004]

However, the ordinary quenching device has a structure in which the steel strip introduced from above vertically is inverted by one conductor roll arranged in the cooling water and conveyed vertically above. Since there is no roll supporting the steel strip between this conductor roll and the roll at the top of the reflow furnace, the steel strip immediately after being introduced into the cooling water in the tank does not come into contact with the roll. A warp in the width direction in which the side surface is convex (hereinafter, referred to as “C warp”) occurs. Therefore, according to the above-mentioned conventional method, even if the cooling liquid is uniformly sprayed in the entire width direction by the spray nozzle immediately before the steel strip enters the cooling water of the quenching tank or in the cooling water, the C strip of the steel strip is accompanied. In addition, since the distance between the steel strip surface and the spray nozzle is different at each point in the width direction, there is a problem that quenching cannot be prevented because the steel strip is not uniformly cooled in the width direction.

The present invention has been made by paying attention to such problems of the prior art, and in the quenching method for tin-plated steel strip, the above-mentioned C that occurs in the steel strip immediately after being introduced into the cooling water. An object of the present invention is to provide a method capable of performing uniform cooling in the width direction of a steel strip by eliminating the warp and effectively preventing the occurrence of quench stain, and an apparatus therefor.

[0006]

In order to achieve the above object, the invention according to claim 1 introduces a tin-plated steel strip after reflow into a quench tank from above and arranges it in this quench tank. While changing the conveying direction of the steel strip in the conductor roll upward, while quenching the steel strip with cooling water in the quench tank, at least one position immediately before and immediately after the introduction into the quench water of the quench tank, In a quenching method for a tin-plated steel strip, which sprays cooling water uniformly across the width of the steel strip with a cooling water spraying device, the cooling water spraying is located upstream of the conductor roll and located at the most downstream side. A quenching method for a tin-plated steel strip, characterized in that the steel strip is supported by a support roll in cooling water on the downstream side of the apparatus.

The invention according to claim 2 is characterized in that, in the method according to claim 1, the steel strip surface is pushed by a predetermined amount by the support roll. Claim 3
The invention according to, is installed below the reflow furnace, quenching the tin-plated steel strip after reflow is rapidly cooled by cooling water, and the conveying direction of the steel strip in cooling water disposed in the quenching tank. A conductor roll that changes upward, a cooling water spraying device that sprays cooling water evenly across the width of the steel strip at at least one position immediately before and after introduction into the quench tank, and upstream of the conductor roll. Of the tin-plated steel strip, which is a side and is disposed in cooling water on the downstream side of the cooling water spraying device disposed on the most downstream side, and which comprises a support roll supporting the steel strip. A quench device is provided.

According to a fourth aspect of the present invention, in the apparatus of the third aspect, the support roll is arranged at a position where the steel strip surface is pushed in by a predetermined amount.

[0009]

According to the method of claims 1 and 2, the reflowed tin-plated steel strip introduced into the quench tank from above is the upstream side of the conductor roll and the cooling water located at the most downstream side. Since it is supported by the support rolls in the cooling water on the downstream side of the spraying device, the above-described C warp is unlikely to occur in the steel strip immediately after being introduced into the cooling water. As a result, the distance between the cooling water spraying device and the steel strip surface becomes the same or almost the same at each point in the width direction, so that cooling by the cooling water spraying device is performed uniformly in the width direction of the steel strip.

In particular, according to the method of claim 2, the support roll pushes the steel strip surface by a predetermined amount, so that the effect of preventing the above-described C warpage from occurring in the steel strip immediately after being introduced into the cooling water becomes large. That is, there is a correlation between the amount of indentation of the steel strip surface by the support roll and the degree of the C warp (C warp amount), and the amount of C warp is unlikely to occur depending on the diameter of the conductor roll and the support roll, the pushing direction, and the like. There is a pushing amount that can be performed, and this corresponds to the predetermined amount.

According to the apparatus of claims 3 and 4, the tin-plated steel strip after reflow is introduced into the quench tank from above, and is rapidly cooled by cooling water while being conveyed upward by the conductor rolls in this quench tank. Along with the conductor roll, in the cooling water on the downstream side of the cooling water spraying device arranged on the most downstream side, and supported by the support roll, the steel strip immediately after being introduced into the cooling water is described above. In a state in which the C warp is less likely to occur, the cooling water is uniformly sprayed over the entire width direction by the cooling water spraying device at at least one position immediately before and immediately after being introduced into the quench tank. As a result, when the cooling water is sprayed, the distance between the cooling water spraying device and the steel strip surface is the same or substantially the same at each point in the width direction, so that the cooling by the cooling water spraying device is performed in the width direction of the steel strip. It is done uniformly.

Particularly, in the apparatus of claim 4, since the steel strip surface is pushed by the support roll by a predetermined amount,
Similarly, the effect of not causing the above-mentioned C warpage in the steel strip immediately after being introduced into the cooling water becomes large.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of a quenching apparatus for tin-plated steel strips according to claims 3 and 4. This apparatus includes a quench tank 2 installed below the reflow furnace 1, a conductor roll 3 installed in the lower portion of the quench tank 2, and a tin-plated steel strip S emerging from the reflow furnace 1 in a predetermined path. A guide member 4 installed between the reflow furnace 1 and the quench tank 2 to be introduced into the quench tank 2 by a line, and cooling provided just below the water surface of the cooling water 21 stored in the quench tank 2. It is composed of a water spraying device 5 and support rolls 6 and 7 installed in series between the cooling water spraying device 5 and the conductor roll 3.

The guide member 4 is a guide plate in which plate members extending in the plate width direction are opposed to each other with a pass line of the tin-plated steel strip S interposed therebetween, and a slit for passing the tin-plated steel strip S is provided on the lower surface thereof. 41, and a slit-shaped spray nozzle (cooling water spraying device) 42 having a slit extending in the entire plate width direction inside thereof.
2, the cooling water is uniformly sprayed over the entire width direction on the tin-plated steel strip S immediately before being introduced into the quench tank 2.

The cooling water spraying device 5 is provided with the cooling water 21.
It consists of a slit-shaped spray nozzle having slits across the entire width of the plate, sandwiching the pass line of the tin-plated steel strip S immediately below the water surface inside, and by the spray nozzle,
The cooling water is uniformly sprayed over the entire width direction on the tin-plated steel strip S immediately after being introduced into the quench tank 2.

Of the support rolls 6 and 7, the support roll 6 disposed on the upstream side has a tin-plated steel strip S so that the tin-plated steel strip S can be along a path line extending vertically downward from the reflow furnace 1. Is fixedly installed at a predetermined position inside (on the side that contacts the conductor roll 3). Also,
The support roll 7 arranged on the downstream side is arranged outside the tin-plated steel strip S, and is horizontally movably installed so that the steel strip surface can be pushed inward.

According to this apparatus, the tin-plated steel strip S reflowed in the reflow furnace 1 is introduced into the quench tank 2 from above via the guide plate 41 of the guide member 4, and the conductor rolls are introduced in the quench tank 2. In the state in which the steel strip S immediately after being introduced into the cooling water 21 is less likely to be C-curved as described above while being rapidly cooled by the cooling water 21 while being conveyed upward in 3 and supported by the support rolls 6 and 7. By the spray nozzle 42 of the guide member 4 and the cooling water spraying device 5, the cooling water is sprayed uniformly in the entire width direction both immediately before and immediately after the introduction into the quench tank 2.

As a result, the method according to claims 1 and 2 is implemented, and at the time of spraying the cooling water in the guide member 4 and the cooling water spraying device 5, the distance between the spray nozzle and the steel strip surface is the same at each point in the width direction. Or, almost the same, cooling by spraying cooling water is uniformly performed in the width direction of the tin-plated steel strip S. Here, when the diameter of the conductor roll 3 is set to 400 mm and the diameters of the support rolls 6 and 7 are both set to 120 mm by this device, the support roll 7
FIG. 2 is a graph showing the results of examining the correlation between the indentation amount of the steel strip S and the above-described C warp amount. This C warp amount is
As shown in FIG. 3, the degree of protrusion of the surface on the side not contacting the conductor roll 3, which is the perpendicular line drawn from the protruding tip of the C-warp surface S _C to the reference line S ₀ when the steel strip S is a flat surface. It means the distance L.

As can be seen from this graph, when the steel strip surface is pushed inward by the support roll 7 in the above-mentioned apparatus, when the pushing amount is increased from "0", the C warpage amount is lowered and the predetermined amount (here However, if the pushing amount is further increased from here, the protrusion of the surface on the side in contact with the conductor roll 3 (C warpage is “−”)
When the pushing amount is further increased, the C warp amount increases again after passing through “0” at a predetermined amount (here, 18 mm).

That is, in this case, since there are two pushing amounts for which the C warping amount becomes "0", the C warping amount is set by arranging the support roll 7 so that the pushing amount becomes either value. When the amount is "0", cooling by spraying cooling water can be performed quite uniformly in the width direction of the steel strip. Further, with this device, the diameter of the conductor roll 3 is 400 mm, the diameters of the support rolls 6 and 7 are both 120 mm, the pushing amount of the steel strip S by the support roll 7 is “0” or 10 mm, and the cooling water spray is cooled. Only immediately after introduction into the cooling water 21 by the water spraying device 5, or just before introduction into the cooling water 21 by the guide member 4, or both, a plate thickness of 0.22 mm,
The tin-plated steel strip S having a plate width of 842 mm was quenched, and the amount of C warpage generated at that time and the quench stain generation rate of the obtained tin-plated steel sheet were examined. In addition, the quenching stain generation rate here means the ratio of the weight of the quenching stain generation part with respect to the weight before quenching.

As comparative examples, support rolls 6 and 7 are used.
In the case where the same quenching treatment was performed in the same apparatus as the above apparatus except that neither was installed, the amount of C warpage that occurred and the quench stain of the obtained tin-plated steel sheet were examined. The results are shown in Table 1 below.

[0022]

[Table 1]

As can be seen from the table, when the pushing amount of the steel strip S by the support roll 7 is 10 mm, the C warping amount becomes "0", and the quench stain generation rate becomes "0" by both cooling water spraying. It can be
Also, even if only one of the cooling water is sprayed,
The quench stain generation rate was 0.2%, which was close to "0".

Further, when the pushing amount of the steel strip S by the support roll 7 is "0", the C warping amount is 15 mm, and the quench stain generation rate is 1.0% only by spraying one of the cooling waters. To 0.8% by both cooling water sprays, and when neither of the support rolls 6 and 7 is installed, only one cooling water spray alone gives 1.7%, and both cooling water sprays 1. Compared with 5%, the incidence of quenching stain is low. As a result, there is no pushing of the steel strip S by the support roll 7,
It can be seen that even if the steel strip S is simply held on the pass line as it is (vertical direction in this case), the effect of lowering the quench stain generation rate than in the conventional case can be obtained. In addition,
If neither of the support rolls 6 and 7 is installed,
A large vibration occurred in the steel strip S at the position where it was introduced into the cooling water 21.

As described above, in the device of the first embodiment,
Generation of quench stain is effectively prevented, and a tin-plated steel sheet having excellent surface properties can be obtained. FIG. 4 shows claim 3.
It is a schematic block diagram which shows the 2nd Example of the quenching apparatus of the tin-plated steel strip which concerns on 4 and 4, Instead of the support rolls 6 and 7 in the apparatus of the 1st Example shown in the said FIG. The device has the same configuration as the device of the first embodiment except that it is arranged. Therefore, except for the following points, the same operation and effect as the first embodiment are obtained.

Of the support rolls 61, 71, the support roll 61 disposed on the upstream side is the reflow furnace 1
The tin-plated steel strip S is fixedly installed at a predetermined position outside the tin-plated steel strip S (on the side not contacting the conductor roll 3) so that the tin-plated steel strip S runs along a path line extending vertically downward from the. Further, the support roll 71 arranged on the downstream side,
It is arranged inside the tin-plated steel strip S and is movably installed in the horizontal direction so that the steel strip surface can be pushed outward.

With this apparatus, when the diameter of the conductor roll 3 is 400 mm and the diameters of the support rolls 6 and 7 are both 120 mm, the pushing amount of the steel strip S by the support roll 71 and the above-mentioned C warp amount are obtained. The result of examining the correlation of is shown in a graph in FIG. As can be seen from this graph, in the case where the steel strip surface is pushed outward by the support roll 71 in the apparatus, if the pushing amount is increased from "0", the amount of C warpage is lowered and the predetermined amount (here, 10) is obtained.
mm) becomes “0”, and when the pushing amount is further increased from this, the surface on the side in contact with the conductor roll 3 is protruded (the C warpage amount is “−”) and increases.

That is, in this case, there is one indentation amount at which the C warp amount becomes "0", and the C roll amount becomes "0" by arranging the support roll 71 so as to be this value. Therefore, it becomes possible to perform cooling by spraying cooling water completely uniformly in the width direction of the steel strip.
As described above, also in the apparatus of the second embodiment, the occurrence of quench stain is effectively prevented, and a tin-plated steel sheet having excellent surface properties can be obtained.

In each of the above-described embodiments, only the case where two support rolls are provided has been described, but the number of support rolls installed is not limited to this, and may be one or three or more. If there is at least one, better results than before can be obtained.

[0030]

As described above, according to the first and second aspects.
According to the above method, the occurrence of quench stain can be effectively prevented by a simple method of supporting the tin-plated steel strip by the support roll at a predetermined position in the cooling water in the quench tank. As a result, there is an effect that a tin-plated steel sheet having excellent surface properties can be easily obtained.

According to the apparatus of claims 3 and 4,
The advantage that the methods of claims 1 and 2 are preferably implemented can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a quenching apparatus for tin-plated steel strips according to claims 3 and 4.

FIG. 2 is a graph showing a correlation between a C warp amount and a pushing amount of a steel strip surface by a support roll in the first embodiment.

FIG. 3 is a schematic diagram showing a definition of a C warp amount in an example.

FIG. 4 is a schematic configuration diagram showing a second embodiment of the quenching apparatus for tin-plated steel strips according to claims 3 and 4.

FIG. 5 is a graph showing a correlation between a C warp amount and a pushing amount of a steel strip surface by a support roll in a second example.

[Explanation of symbols]

 1 Reflow Furnace 2 Quench Titanium 3 Conductor Roll 5 Cooling Water Spraying Device 6 Support Roll 7 Support Roll 21 Cooling Water 42 Spray Nozzle (Cooling Water Spraying Device) 61 Support Roll 72 Support Roll S Tinned Steel Strip

Claims (4)

[Claims] 1. A tin-plated steel strip after reflow is introduced from above into a quench tank, and a conductor roll disposed in this quench roll changes the conveying direction of the steel strip upward while While rapidly cooling the steel strip with cooling water, at least one position immediately before and immediately after the introduction of the quenching water into the cooling water, the cooling water spraying device to uniformly cool the cooling water across the width of the steel strip. In a quenching method of a tin-plated steel strip to be sprayed, in the cooling water on the upstream side of the conductor roll and on the downstream side of the cooling water spraying device arranged on the most downstream side, it is possible to support the steel strip by a support roll. Characteristic method of quenching tin-plated steel strip. 2. The quenching method for tin-plated steel strip according to claim 1, wherein the support roll pushes the steel strip surface by a predetermined amount. 3. A quenching tank installed below the reflow furnace to quench the reflowed tin-plated steel strip with cooling water, and a quenching tank disposed in the quenching tank for changing the conveying direction of the strip in the cooling water. A conductor roll that changes upward, a cooling water spraying device that sprays cooling water evenly across the width of the steel strip at at least one position immediately before and after introduction into the quench tank, and upstream of the conductor roll. Of the tin-plated steel strip, which is a side and is disposed in cooling water on the downstream side of the cooling water spraying device disposed on the most downstream side, and which comprises a support roll supporting the steel strip. Quench device. 4. The support roll is arranged at a position where the steel strip surface is pushed in by a predetermined amount.
Quenching device for tin-plated steel strip as described.