JPH01272775A - Method for continuously plating metallic sheet - Google Patents

Abstract

PURPOSE:To stably form a molten metal plating layer on the surface of a band steel in an extremely short time by bringing a plating metal into contact with the surface of the continuously moving band steel, and projecting high energy onto the contact point and its vicinity. CONSTITUTION:A steel sheet 1 preheated to about 450 deg.C, for example, is moved in the direction as shown by the arrow, a plating material 2 of Zn, etc., preheated to about 350 deg.C by a heater 3 such as an IR heater is pressed on the surface of the two sets of pinch rolls 4a and 4b and 4c and 4d, the tip of material 2 is simultaneously irradiated with laser light, an electron beam, plasma, etc., from a high-energy body 5 to respectively heat the contact point A between the band steel 1 and the plating material and its vicinity, hence the tip of the material is melted, and a Zn plating layer 2a having a requisite thickness is formed on the steel sheet 1 in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for continuously plating the surface of a metal plate.

[Conventional technology]

Conventionally, the hot-dip plating method, which has been widely used to form a plating film on the surface of copper strips, has many problems in terms of the quality and type of plating, and many efforts have been made to solve these problems. Improvement plans have been proposed and implemented, but none of them have reached a fundamental solution in terms of workability, productivity, safety, cost, etc.

Therefore, the present inventors have proposed a new continuous plating method that is completely different from the conventional hot-dip plating method. Figure 3 schematically shows the principle of this plating method.
and a molten layer of plated metal (2
1), and the plated metal material (20) is formed on a metal plate (
10), the molten plating metal is continuously deposited as a plating film (22) on the surface of the moving metal plate (10).

[Problem to be Solved by the Invention 1] In the above method, the plated metal material (20) is heated and melted immediately before reaching the contact point with the metal plate (10), or the metal plate (10) and the plated metal material are heated and melted. (20) is preheated before these contact points, and the plating metal material (20) is heated and melted mainly by the sensible heat of the metal plate (10) at the contact point, thereby forming a molten layer (21) of the plating metal. I am doing it. The thickness H of the plating film (22) formed by forming such a molten layer (21) is as follows.

The moving speed of the metal plate (10) is U, the plated metal material (20)
When the supply speed of is V and the thickness of the plated metal material (20) in the direction of metal plate movement is W, it is given by H=w−L.

Here, the moving speed U of the metal plate (10) and the plating metal material (
When the thickness W of the plated metal material (20) is kept constant, in order to increase the coating amount, in other words, the thickness H of the plated film (22), the supply speed V of the plated metal material (20) must be increased. Alternatively, if the line speed U is increased and the thickness H is to be kept constant, the supply speed V
must be increased. The supply speed V depends on the heating capacity of the metal plate (10) and the plated metal material (20) as long as the heating or preheating method of the metal plate (10) and the plated metal material (20) as described above is performed. Ru.

These actual heating methods include induction heating,
Infrared heater, ceramic heater.

This method involves heating from the outside using a heater made of resistance wire or the like. However, when the temperature is raised by these heating methods, the temperature rises in a gentle curve as shown in FIG.

If the response of the heating control is poor in this way, when implementing the continuous plating method described above, the amount of plating deposited will vary at the start of the process, and when changing the line speed or the amount of plating deposited, it will not be possible to instantly increase the amount to the target value. Moreover, an ideal change that maintains this is impossible, and the yield will deteriorate.

In addition, when melting the plated metal material (20) with the metal plate (10), the amount of plating deposited is greatly affected by the temperature of the metal plate (10), so the plate temperature must be kept constant at the point of contact. It is necessary to keep it.

The present invention was created in view of the above-mentioned problems, and aims to improve the preheating and heating methods for metal plates and plated metal materials, and to maximize the advantages of the above-described continuous metal plate plating method. It is something.

[Means for solving problems]

Therefore, in the present invention, a high-energy body is irradiated near the contact point between the metal plate and the plated metal material to heat the metal plate and the plated metal material at or near the contact point.

The high-energy body referred to in the present invention refers to a substance such as a laser beam, an electron beam, or a plasma that can instantaneously impart high energy to an object by irradiating it. Used to instantly heat up the irradiated area. However, when performing this irradiation, the extent to which the plating metal is dissolved (for example, for Zn, approximately 4
(20°C or higher and 900°C or lower), and the temperature must be controlled within a range that does not evaporate, such as above the boiling point. Furthermore, the configuration of the present invention may be used in combination with a configuration that performs heating in the conventional method, and used only at the start-up of the above-described continuous plating method, when changing the line speed, or when changing the amount of plating deposited. . Furthermore, it is preferable that the irradiation is applied mainly to the plated metal material and used for preheating or melting it. When melting plated metal materials using the sensible heat of the metal plate, considering that variations in the amount of coating due to changes in the plate temperature become a major problem, it is necessary to use irradiation to eliminate the plate temperature fluctuations and maintain the temperature at a constant temperature. Although it is possible to do this, since the energy used is small enough to change the plate temperature, most of the irradiation energy will be given to the plated metal material that will actually be melted.

Furthermore, if a large amount of energy is applied to the metal plate, the metal plate will be heated rapidly, which will deteriorate the shape of the plate, which is undesirable for operation, so care must be taken.

[For production]

In the present invention, it is possible to instantaneously apply high energy to the contact point or its vicinity to rapidly heat the irradiated area, resulting in extremely good heating control response.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the accompanying drawings.

Figure 1 shows the equipment for carrying out continuous single-sided galvanizing according to the method of the present invention, in which (1) is a copper strip which is a metal plate, (2)
is a galvanized metal material.

The copper strip (1) has a width of 1260m+o and is heated to about 450°C with an infrared heater (not shown) to spread at a rate of 120m/mi.
While flowing continuously at a line speed of
It is fed out in the vertical direction by a) to (4d) and makes continuous contact at point A.

Usually, the galvanized material (2) is melted at the point of contact by the sensible heat of the steel strip (1), and an amount of coating film (2a) of about 40 g/I is obtained.

However, when attempting to restart such equipment, the heating device described above does not warm itself sufficiently when it starts up, so the temperature rises in a gentle heating curve, during which time the galvanized material (2 ) also increases slowly. As a result, the amount of plating deposited gradually increased and did not reach 40 g/m during that time, resulting in poor yield.

In this embodiment, therefore, the laser beam oscillator (5) is configured to irradiate the vicinity of the point A with laser beam.

This laser beam oscillator (5) may be one that combines an oscillator that emits a laser beam with a scanning device that can scan the laser beam over the target irradiation range, or one that consists only of an oscillator that emits a sheet laser beam. Ru.

Further, as for the irradiation angle, it is better to make it perpendicular to the surface of the object to be irradiated, since it is necessary to make the energy density as high as possible. Then, when the heating device starts up, the laser beam oscillator (5) is used to irradiate the vicinity of point A (mainly the galvanized material (2)) with a laser beam. The energy of the laser beam is approximately 20 kW in order to obtain a coating weight of approximately 40 g1rd from the beginning.

Figure 2 shows an example of the improvement in the amount of plating deposited at the time of start-up as a result of irradiation with such laser light.The broken line shows the case when only indirect heating equipment is used, and the solid line shows the case where the amount of plating is improved at the time of start-up. The case where irradiation was performed together is shown.

In this way, in the case of this example, the response of the heating control is improved, so that the amount of plating deposit reaches the target amount in a very short time, and the yield is improved by 1, and it is clear that the effect is extremely high. Ta. It goes without saying that such laser light irradiation is also effective when changing the line speed or increasing the amount of plating deposited. It is desirable to control the amount of laser light irradiation so that it is gradually attenuated. or.

When the width of the steel strip (1) and the galvanized material (2) is changed, the laser beam oscillator (5) that scans the laser beam is
), by changing the scanning amplitude according to the change width, or in the case of a laser beam oscillator (5) that emits sheet laser beam, by shifting the laser beam oscillation position back and forth with respect to point A. to adjust the irradiation range.

In addition to laser beam irradiation as described above, it is possible to irradiate high-energy bodies with plasma or electron beam irradiation, but when using plasma, it is necessary to use a sheet plasma generator that can emit plasma in a sheet shape. will be used.

〔Effect of the invention〕

According to the method of the present invention described above, the response of heating control is dramatically improved by irradiating the vicinity of the contact point between the metal plate and the plated metal material, so the amount of plating deposited is extremely short. When the continuous plating method proposed by the present inventors is started, when the amount of plating deposited increases in the method, and when the line speed is changed, There are effects such as eliminating variations in the amount of plating deposited and making it possible to change the ideal amount of plating deposit. Moreover, since the temperature of the metal plate can be kept constant by the irradiation, it is also effective in stabilizing the amount of plating deposited and improves the yield.

In the above-mentioned embodiment, the copper strip was moved in the horizontal direction to perform single-sided plating, but for double-sided plating, it is sufficient to install a similar device on the opposite side of the copper strip.

Further, the direction is not limited to the horizontal direction, and, for example, the vertical direction is also possible. Needless to say, there is no problem whether the steel strip runs in the direction from top to bottom or from bottom to top.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of equipment for implementing the method of the present invention;
The figure is a graph showing the change in coating weight at start-up achieved by the above equipment, Figure 3 is an explanatory diagram schematically showing the principle of the continuous plating method proposed by the present inventors, and Figure 4 is indirect heating. FIG. 3 is a graph diagram showing the state of temperature increase of a plated metal material etc. by the apparatus. In the figure, (1) is a steel strip, (2) is a galvanized material, (3) is an infrared heater, (4a) (4b) (4c) (4d
) is a pinch roll, (5) is a laser beam oscillator, (10)
(20) a plated metal plate, (21) a molten layer, and (22) a plated film. Figure 2 Q Time 3 Calculation 4 Figure Time

Claims (5)

[Claims] (1) The plating is melted by bringing a plating metal material into contact with a moving metal plate, forming a molten layer of plating metal at the contact point, and continuously supplying the plating metal material to the metal plate. In a continuous metal plate plating method in which metal is continuously deposited as a plating film on the surface of a moving metal plate, a high-energy object is irradiated near the contact point to remove the metal plate and plated metal material at or near the contact point. A continuous plating method for metal plates, characterized by preheating or overheating. (2) In the method for continuous plating of metal plates described in the previous section, irradiation with a high-energy body is mainly performed on the plating metal material,
A continuous plating method for a metal plate according to claim 1, characterized in that the metal plate is preheated or melted. (3) A continuous plating method for a metal plate according to claims 1 and 2, characterized in that a laser beam is used as the high-energy object to be irradiated. (4) A continuous plating method for a metal plate according to claims 1 and 2, characterized in that an electron beam is used as the high-energy body to be irradiated. (5) The continuous plating method for metal plates according to claims 1 and 2, characterized in that plasma is used as the high-energy body to be irradiated.