JP2698516B2 - Rolling equipment for hot metal plating bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll apparatus in a hot-dip metal plating bath for obtaining a hot-dip coated steel sheet having excellent uniformity of coating weight.

[0002]

2. Description of the Related Art The demand for hot-dip galvanized steel sheets, mainly alloyed hot-dip galvanized steel sheets, has been increasing sharply in recent years along with the increasing trend of rust prevention in the industrial world. The level of quality that is provided is also becoming more sophisticated than before. Above all, the uniformity of the coating weight has a dominant effect on the corrosion resistance, weldability, adhesion of the coating layer, etc. of the plated steel sheet, and therefore, the importance of the technique of making the coating weight uniform is increasing.

[0003] The first major cause of the uniformity of the coating weight is the warpage in the width direction of the plated steel strip at the plating amount control position, that is, the gas wiping position (hereinafter referred to as C warpage). As a result, a difference occurs in the distance between the gas spray nozzle and the plated steel strip at the end and the center in the width direction of the plated steel strip. The purpose is to make the plating adhesion amount non-uniform. The second factor is vibration of the plated steel strip at the gas wiping position, so-called fluttering. Fluttering is a phenomenon in which the position of the plated steel strip oscillates with time based on the center position of the gas blowing nozzle pair.At a certain moment, the surface of the plated steel strip approaches the nozzle and the gas collision pressure on the surface side decreases. As a result, the surface plating adhesion amount becomes thicker than that of the rear surface. This fluttering is to periodically reverse the surface adjacent to the gas spray nozzle, and if considered on one surface, thick and thin portions with a large amount of coating adhered periodically appear in the longitudinal direction of the plated steel strip. Will be. Such uniformity of the coating weight in the longitudinal direction results in non-uniformity in the longitudinal direction of the corrosion resistance, plating adhesion, weldability, and other qualities. This leads to a difference in color tone on the plating layer surface,
A color tone pattern in the longitudinal direction appears, resulting in poor appearance.

Conventionally, there have been disclosed techniques for improving the uniformity of the coating amount in the width direction of the plated steel strip and some techniques for improving the uniformity of the coating amount in the longitudinal direction of the coated steel strip. There is no example of a technique for simultaneously solving the uniformity of the plating amount in the width direction and the longitudinal direction of the band. As a technique for improving the unevenness in the sheet width direction, that is, the C warpage of the plated steel strip at the wiping portion, for example, JP-A-2-265854
Japanese Patent Laid-Open Publication No. H11-163873 also proposes a technique for adjusting the position of a sink roll and a support roll in the horizontal direction. However, the present inventors have studied in detail that the technique described in the above-mentioned publication eliminates C warpage. For this reason, the rigidity of the plated steel strip itself is reduced, rather, fluttering is emphasized, and the amount of plating applied in the longitudinal direction varies, and the above-described poor color tone pattern in the longitudinal direction becomes apparent. Also, it is not impossible to use the support roll without driving, but even if the support roll is not driven, it will only cause poor rotation,
Rather, fluttering becomes apparent due to poor rotation.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and simultaneously reduces the non-uniformity of the coating amount in both the width direction and the longitudinal direction of the coated steel strip. An object of the present invention is to provide a roll apparatus in a hot-dip metal plating bath at low cost to obtain a hot-dip coated steel sheet having an excellent uniformity of the applied coating weight.

[0006]

A roll apparatus in a molten metal plating bath according to the present invention which solves the above-mentioned problems is a roll apparatus in a molten metal plating bath in which a sink roll and a support roll are arranged in a plating tank. In the above, at least the support roll located immediately above the sink roll is a non-driving roll, and at least one
And the support roll can be controlled in the horizontal direction orthogonal to the roll axis.
In such a molten metal plating bath roll apparatus, a support roll is a support roll pair consisting of the non-driving roll and an upper roll for defining a pass line, and at least one of the support roll pairs is a plating bath depth. It is more preferable that the position can be controlled also in the direction.

[0007]

In the above-described apparatus for rolling in a molten metal plating bath, the plating steel strip sent to the molten metal plating bath in the plating tank through the snout is converted in the sink roll by a passing direction through the support roll. The hot-dip metal plating is performed on the front and back surfaces while being pulled up, as in the case of this type of conventional apparatus. However, in the present invention, an appropriate inter-mesh amount is set according to the thickness and steel type of the plated steel strip. Sink roll and at least one
If both the support roll and the support roll are controlled in the horizontal direction perpendicular to the roll axis, the support roll positioned immediately above the sink roll is a non-drive roll, and at the same time, the C warpage and the fluttering are prevented. Both are eliminated, and the nonuniformity of the coating amount in both the width direction and the longitudinal direction of the plated steel strip can be simultaneously solved.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plating tank in which a molten metal plating bath is placed, 2 is a sink roll which is installed at the bottom of the plating tank 1 and converts the passing direction of the continuously plated steel strip 11 which is continuously fed, 3 Is a support roll installed above the sink roll 2, and the sink roll 2 and the support roll 3 are located in a molten metal plating bath. The support roll 3 is a single roll in the first embodiment shown in FIG. 1, but is a support roll pair composed of a lower roll 3a and an upper roll 3b in other embodiments shown in FIGS. . And, at least one of the support rolls 3 located immediately above the sink roll 2 is a non-driving roll. That is, when the support roll 3 is a single roll, this single roll is used as a non-driving roll,
When the support roll 3 is a support roll pair, the lower roll 3a located immediately above the sink roll 2 is a non-drive roll. Also, at least the sink roll 2
Use one support roll with water perpendicular to the roll axis.
Position control is possible in the horizontal direction. Note that at least one
One support roll 3 is a support roll as shown in FIG.
This support role when roll 3 is a single role
3 itself, while supporting as in other embodiments
When there are two or more rolls 3, at least one of them
At least one support role,
The position of both the sink roll 2 and the sink roll 2 can be controlled in the horizontal direction orthogonal to the roll axis, as shown in FIG. Further, when the support roll 3 is a support roll pair as shown in FIGS. 2 to 4, at least one of the lower roll 3a and the upper roll 3b can be position-controlled in the plating bath depth direction. The means for rotating each of the sink rolls 2 and the means for controlling the position of the sink rolls 2 and the support rolls 3 in the horizontal direction may be a well-known rotating mechanism or position control mechanism.
Generally, when the support roll is driven, for example, as shown in FIG.
Is rotated by a motor 6. In the figure, reference numeral 7 denotes a gas spray nozzle which is installed above the support roll 3 at a position higher than the surface of the molten metal plating bath, and 8 denotes a snout.

When such a roll apparatus in a molten metal plating bath is incorporated in a continuous molten plating line, a snout 8
When the plated steel strip 11 is fed into the molten metal plating bath in the plating tank 1 through the through-hole, the sheet passing direction is changed in the sink roll 2 and the plated steel strip 11 is pulled upward through the support roll 3. 11 is to be subjected to hot-dip metal plating, but in the present invention, both the sink roll 2 and at least one support roll are in a horizontal direction perpendicular to the roll axis, that is, perpendicular to the roll length direction. The horizontal position can be controlled in the direction, and the roll position can be set under appropriate conditions determined according to the plate thickness and the steel type of the plated steel strip 11, so that the C warpage at the wiping position of the plated steel strip 11 is eliminated and the plated steel strip is removed. 11 makes it possible to equalize the amount of plating in the plate width direction. In addition, since the sink roll 2 and the support roll 3 located immediately above the sink roll 2 are non-drive rolls, even if the rigidity of the plated steel strip 11 becomes extremely low due to the elimination of the C warp, it becomes a source of fluttering. The vibration of the support roll 3 itself disappears, and the coating amount of the plating in the longitudinal direction of the plated steel strip 11 can be made uniform. Thus, in the present invention, both the C warpage and the fluttering can be eliminated. The nonuniformity of the coating amount in both the plate width direction and the longitudinal direction of the steel strip 11 can be simultaneously solved.

[0010] and the sink roll 2 in the present invention, at least
The reason why both the one support roll and the one support roll can be position-controlled in the horizontal direction orthogonal to the roll axis is to eliminate the C warpage at the wiping position of the plated steel strip 11 as described above. That is, when the plated steel strip 11 passes through the support roll 3, it is wound around the support roll 3, so that the plated steel strip 11 undergoes bending deformation in the longitudinal direction. Since the curved surface and the outer surface have different curvatures depending on the thickness of the sheet, the amount of deformation and bending stress received are also different. This bending stress is applied to the plated steel strip 11.
If the yield stress exceeds the yield stress, the plated steel strip 11 is plastically deformed. However, since there is a difference in stress between both sides of the plated steel strip 11, the amount of deformation differs between the front and the back, resulting in a warpage. If the roll position is changed so that the amount of strain applied to the front and back surfaces of the plated steel strip 11 is balanced by using this phenomenon, the winding of the plated steel strip 11 around the support roll 3 is controlled, and the front and back surfaces of the plated steel strip 11 are controlled. The deformation amounts are equal, and the plated steel strip 11 is free from warpage, and the amount of plating applied to the plated steel strip 11 in the plate width direction is made uniform.

However, the sink roll 2 disposed in the hot-dip metal plating bath and at least one support
Even if it is possible to eliminate the C warpage only by enabling the position control of both the trawl and the horizontal direction orthogonal to the roll axis, as described above, the unevenness of the coating amount of the plated steel strip 11 in the longitudinal direction is as described above. Not only can not be eliminated,
Rather, fluttering of the plated steel strip 11 is promoted by eliminating C warpage. The reason is that, when C warpage is present, the C warp itself increases the rigidity of the plated steel strip 11 at the wiping position by giving the plated steel strip 11 a curvature in the width direction, thereby reducing the wiping gas pressure. While having resistance to fluttering,
When the C warpage is eliminated, the plated steel strip 11 becomes flat in the width direction, the rigidity is reduced and the resistance to fluttering is reduced, and the fluttering is easily performed by a slight fluctuation of the wiping gas pressure and a different peripheral speed motion of the support roll. Because it wakes up.

The inventor of the present invention eliminates the C warpage of the plated steel strip to make the coating amount of the plated steel strip 11 uniform in the sheet width direction and at the same time eliminates the C warp, thereby conversely promoting fluttering, As a result of further study to eliminate the phenomenon that the uniformity of the coating amount of the plating decreases, one of the main causes of the fluttering is to connect the spindle 5 for driving the support roll 3 as shown in FIG. And found that the essential cause of fluttering can be eliminated by eliminating the drive of the support roll 3 itself. That is, the spindle 5 and the joint 4, which are essential for driving the support roll, are inevitable for a certain number of unequal-velocity movements determined by the structure during one rotation thereof. The cyclic peripheral speed is given, and as a result, the support roll 3 is vibrated, and the plated steel strip 11 is fluttered.

Therefore, in the present invention, the support roll 3
Of these, at least one located immediately above the sink roll 2 is a non-driving roll, and at least one support roll is provided.
When the roll 3 can be controlled in the horizontal direction together with the sink roll 2, the vibration itself of the support roll 3 which causes fluttering even when the C warpage is eliminated and the rigidity of the plated steel strip 11 becomes extremely low. By eliminating both the C warpage and the fluttering, non-uniformity of the coating amount in both the plate width direction and the longitudinal direction of the plated steel strip 11 was successfully solved at the same time. Therefore, at least one of the support rolls 3 located immediately above the sink roll is used as a non-driving roll in order to eliminate the cause of fluttering, and the sink roll 2 is used in order to eliminate C warpage at the wiping position.
It is an essential requirement of the present invention to combine the control of the position and the at least one support roll with the position controllable in the horizontal direction perpendicular to the roll axis, and it is not necessary to simply use the support roll 3 without driving. The object of the present invention cannot be achieved.

That is, the non-driving of the support roll 3 eliminates the vibration source of the support roll 3, but it is naturally impossible to control the amount of bending strain and eliminates the C warpage when the passing condition is changed. The contact between the plated steel strip 11 and the support roll 3 becomes non-uniform due to the presence of the C warp, resulting in poor rotation of the support roll 3 and a stable production. On the other hand, in the present invention, the sink roll 2
Eliminating C warpage by controlling the position of at least one support roll in the horizontal direction perpendicular to the roll axis,
For the first time, the dispersion of the coating weight in the width direction and the longitudinal direction of the plated steel strip 11 was simultaneously eliminated by simultaneously performing the elimination of the fluttering by the non-driving of the support roll 3. It is a technology that responds to the demand for conversion.

[0015] At least one support roll
According to the present invention, in which both the sink roll 2 and the sink roll 2 are controlled in the horizontal direction perpendicular to the roll axis to eliminate the C warpage and to disable the support roll 3, the width direction of the plated steel strip 11 is used. And a completely new effect other than that the variation in the plating amount in the longitudinal direction can be eliminated at the same time. In other words, the uniform contact between the plated steel strip 11 and the support roll 3 is realized only by the elimination of the C warpage and the elimination of the fluttering. Therefore, the micro-slip and the local high surface pressure contact caused by the non-uniform contact are avoided. This makes it possible to eliminate micro-scratch flaws, which were not possible with the conventional hot-dip coated steel sheet manufacturing technology, and it is possible to further ensure excellent appearance quality. Such an effect is due to at least one support
In addition to controlling the position of the support roll 3 in the horizontal direction perpendicular to the roll axis, the support roll 3
This is not something that can be realized at all. Furthermore, by avoiding such micro-slip and local high surface pressure contact, the roll life is greatly improved compared to the conventional type, and it is possible to reduce costs and improve productivity by reducing the frequency of roll conversion. became.

It should be noted that the non-drive of the support roll 3 can be achieved by making at least the support roll 3 immediately above the sink roll 2 a non-drive roll. When a single support roll as shown in FIG. A non-driving roll may be used for one support roll, and when a support roll pair as shown in FIG. 2 is used, at least the lower roll 3a
A non-driving roll may be used for this. The reason for this is that when a pair of support rolls is used, the angle of entry of the drive transmission shaft into the bath with respect to the deeper lower roll 3a in the hot-dip metal plating bath is large, and the generation of vibrations in this lower roll 3a is remarkable. It is. When the support roll 3 is a pair of support rolls, not only the lower roll 3a but also the upper roll 3b may be non-driven. In this case, the effect of the present invention is of course exerted to the maximum. is there.

On the other hand, the rolls whose position can be controlled in the horizontal direction perpendicular to the roll axis to eliminate C warpage are the sink roll 2 and at least one support roll as described above. that's all

Further, the support roll 3 in the hot-dip metal plating bath is a support roll pair composed of the above-mentioned non-driven lower roll 3a and the upper roll 3b for defining the pass line. If one of them is made position controllable in the plating bath depth direction, a more preferable C warpage preventing effect can be obtained. That is, the vertical movement control of the support roll 3 in the bath depth direction is to change the winding angle of the plated steel strip 11 around the support roll 3 and the sink roll 2, and the change in the winding angle is similar to the horizontal shift. In addition, by changing the distance between the upper roll 3b and the lower non-driving roll of the support roll pair, the amount of strain per support roll horizontal movement amount, in other words, the accuracy of the strain amount control, can be adjusted. Can be adjusted.

The support roll 3 and the sink roll 2
The roll diameter is not particularly limited. When the support roll 3 is used as a support roll pair, a combination of rolls having different diameters may be used. The support roll 3 may be a hollow roll or any other material. The support roll 3 and the sink roll 2 may also have a bearing structure including conditions for material, surface roughness, surface treatment such as thermal spraying, and the like. There is no limitation. The position control amount and accuracy of the support roll 3 and the sink roll 2 in the horizontal direction and the vertical direction can be selected according to a target level, and the position control method can be any of electric, hydraulic, etc. In order to increase the amount of bending strain caused by the roll, a means for applying tension to the plated steel strip 11 may be provided as necessary. Further, the present invention is applicable to all kinds of alloy plating, aluminum plating and other hot-dip metal plating in which one or more kinds of zinc, iron, manganese, magnesium, aluminum, nickel, chromium, lead, antimony, tin, etc. are contained in zinc. Applicable in common.

[0020]

EXPERIMENTAL EXAMPLES Next, experimental examples of the present invention are shown in the table below together with comparative examples. Cold-rolled steel sheet for deep drawing (sheet thickness 0.80mm and 1.0
mm) as a raw material and passed through the continuous hot-dip plating line at a line passing speed of 120 mpm, and the target value of the coating weight was 60
An alloyed hot-dip galvanized steel sheet was manufactured at g / m ² . The annealing condition of the plated steel strip is 800 ° C. for 60 seconds, thereby securing mechanical properties equivalent to deep drawing use. The tension applied to the steel strip in the range from the annealing furnace cooling zone to the alloying furnace after plating was 2.0 kgf / mm ² , the wiping gas used was normal temperature N ₂ , and the gas ejection pressure was 1.8 kgf / mm. cm ² , and the average distance between the gas blowing nozzle and the steel strip surface was 8 mm.
Under these conditions, the presence / absence of driving of the support rolls and the presence / absence of horizontal / vertical position control of the support rolls and sink rolls are changed as shown in Table 1. And the quality of appearance were measured. The plating adhesion amount was measured according to JIS 0401 at a pitch of 100 mm in both the width direction and the longitudinal direction. The width direction is 15 across the steel strip width of 1.500 mm.
Points and longitudinal directions were also measured at 15 points. When driving the support roll, an electric motor is used, and the joint is a universal joint.
The position of the sink roll was controlled by an electric motor. The diameter of the sink roll is 800 mm, and the diameter of the support roll is 300 mm in the case of Example 6, and the lower roll 2 is a non-driven lower roll 2.
A combination of different diameters of 50 mm, another example was 300 mm for both the upper roll and the lower roll. Each level in Table 1 was passed continuously in numerical order. According to the table below for the actual Kenrei 1 to Experiment Example 6, C warpage of the steel strip width direction of the plating amount control position becomes eliminated by plate width direction plating weight distribution is very uniform, controlled fluttering is simultaneously the longitudinal The variation in the plating amount in each direction is extremely small, and no surface scratch is generated. On the other hand, in the comparative example, the fluttering by the drive of the support roll was remarkable, the uniformity of the plating amount in the longitudinal direction was poor, the appearance of the surface was as large as 0.6% of micro scratches, and the degree of alloying was uneven. The resulting color pattern is severe.
Further, it can be seen that the C warpage is large, the plating amount variation in the plate width direction is large, and surface scratches are also generated.

In the following table, Experimental Example 1 shows the apparatus of the first embodiment shown in FIG. 1, Experimental Example 6 shows the apparatus of the second embodiment shown in FIG. 2, and others show the apparatus of the third embodiment shown in FIG. Numerical values in the support roll position column and the sink roll position column are determined with reference to the position where the sink roll and the support roll surface shown in FIG.
The amount of displacement from the reference position in the illustrated + and-directions is shown .

[0022]

[Table 1]

[0023]

As apparent from the above description, the present invention provides:
It can mass-produce hot-dip coated steel sheets with excellent uniformity of coating weight by simultaneously solving the non-uniformity of coating weight in both the width direction and the longitudinal direction of the coated steel strip. There are also benefits that you can do. Therefore, the present invention is extremely large in that it contributes to the development of the industry as a solution to the problem of the conventional roll apparatus in a hot-dip metal plating bath.

[Brief description of the drawings]

FIG. 1 is a front view schematically illustrating a first embodiment of the present invention.

FIG. 2 is a front view schematically illustrating a second embodiment of the present invention.

FIG. 3 is a front view schematically illustrating a third embodiment of the present invention.

FIG. 4 is a side view showing an example of a support roll driving unit according to the present invention.

FIG. 5 is an explanatory diagram of a position moving direction of a support roll and a sink roll in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating tank 2 Sink roll 3 Support roll 3a Non-driven lower roll 3b Upper roll

Claims (2)

(57) [Claims] In a molten metal plating bath roll device in which a sink roll and a support roll are arranged in a plating tank, at least a support roll located immediately above the sink roll is a non-driving roll, and the sink roll and at least A roll apparatus in a hot-dip metal plating bath for obtaining a hot-dip coated steel sheet having excellent uniformity of coating weight, wherein the position of one support roll can be controlled in a horizontal direction perpendicular to the roll axis. 2. A support roll pair comprising a non-driven lower roll and an upper roll for defining a pass line, wherein at least one of the support roll pairs is position-controllable in a plating bath depth direction. A roll apparatus in a hot-dip metal plating bath for obtaining a hot-dip coated steel sheet having excellent uniformity of coating weight according to claim 1.