JPS6176656A - Plating device - Google Patents

Abstract

PURPOSE:To obtain a plated product having a stabilized quality by controlling the height of the melt surface of a molten plating liq. with air pressure, and carrying out the plating. CONSTITUTION:The air from a compressed air source is introduced into the introducing port 14 of a holding furnace 6 by opening a solenoid valve 33 and closing a diaphragm valve 35 through a solenoid valve 34 to increase the furnace pressure, and melt 7 is forced up into a trough 8 through a stalk 10. When the surface of the forced up melt is detected by a melt surface detector 18, the solenoid valve 33 is closed to stop the compressed air, and the solenoid valve 33 is again opened when the lowering of the melt surface is detected. After a metallic material is plated, the melt 7 remaining in the rough 8 is al lowed to flow into the holding furnace 6 through the stalk 10 by closing the solenoid valve 33, opening the diaphragm valve 35 through the solenoid valve 34, and regulating the internal pressure of the holding furnace 6 to the atmo spheric pressure.

Description

[Detailed description of the invention] <Industrial field of application> This invention A is a material made of aluminum or aluminum alloy (
The present invention relates to a plating apparatus suitable for hot-dip plating of an aluminum material (hereinafter referred to as an aluminum material) with an aluminum alloy.

(Prior Art) The technique of applying a relatively thick plating film of aluminum alloy to a long aluminum material is important in the production of multi-hole tubes for aluminum heat exchangers.

That is, in recent years, there has been a strong desire to reduce the weight of heat exchanger cores from the standpoint of energy saving and cost reduction, and in order to meet this demand, thinning of the fins has been considered. However, when the fins made of plating sheet are made thinner than 0.13 mm, there is a problem that the fins buckle at the temperature of about 800° C. during brazing.

Therefore, it is desirable to braze the bare fins with an extruded multi-hole tube whose outer surface is coated with a brazing material in order to make the heat exchanger core lighter, reduce costs, and improve the corrosion resistance of the tube.

As a method of hot-dip plating aluminum materials such as multi-hole tubes for aluminum heat exchangers with aluminum alloy, there is a method of applying hot-dip plating solution, which is used for bar materials, or a method that is used for plate materials. It is conceivable to apply a method of immersion in a hot-dip plating solution.

<Problems to be Solved by the Invention> However, among the conventional methods described above, it is difficult to form a relatively thick and uniform plating film over the entire material with the method of applying molten plating solution to the material to be plated. This method is particularly unsuitable for use in cases where the aluminum material is a long aluminum tube or an aluminum profile with a complicated shape.

On the other hand, when the aluminum material to be plated is small, the method of immersing it in a hot-dip plating solution does not require any special measures since it can be immersed in the processing solution at a predetermined temperature. Since pipes cannot be easily immersed in the processing solution, and their melting points are similar, there is a risk that the aluminum material may partially become metallized and dissolve while immersed in the hot-dip aluminum plating solution. It has a predetermined thickness necessary as a brazing material for aluminum pipes, etc. It was difficult to form a uniform plating pattern.

<Means for Solving the Problems> The present inventors have conducted extensive research to overcome the problems of plating aluminum materials with aluminum alloys, and as a result have completed the present invention.

That is, one aspect of the present invention comprises a molten metal holding furnace, a trough, and a communication passage connecting the insides of both, and uses air pressure as an operating pressure to push the molten metal in the holding furnace into the trough.

The present invention provides a plating apparatus characterized in that the metal material placed in the trough is immersed in a molten metal plating solution to perform hot-dip plating.

<Example> Next, the apparatus of the present invention will be described according to an illustrated example. FIG. 1 is a longitudinal sectional view of a plating process using the apparatus of the present invention, and A is a preheating block.

B is a plating block, and C is a take-out block.

In the A block, a metal material to be plated, such as an aluminum tube 1, is transferred on a support roller 2 toward the B block, and during this time is heated to a predetermined temperature by a preheating burner 3. 4 is the heat insulating wall of the preheating zone, 5 is the support leg of the preheating zone, and the aluminum pipe l that passed through A block is B
Enter the block. In the B block, 6 is a holding furnace containing a molten metal 7 of a hot-dip plating solution, for example, an aluminum alloy;
is a trough installed above the holding furnace, and 9 is a fixed leg of the trough. The lower part of 10 is in the molten aluminum alloy of the holding core, and the upper part is connected to the communication hole 1 at the bottom of the trough.
This is the stalk connected to 1. 12 and 13 are troughs,
Holding furnace.

and a fixed unit of the stalk. Reference numeral 14 denotes an air introduction hole as an operating source, which is connected to an air introduction circuit as detailed in FIG. 3. 15 and 16 are trough A,
Installed on each side of C block. This is a charging hole and a withdrawal hole for aluminum tubing l.

17 is a hot water receiving box for receiving molten hot water, and 18 is a hot water level detection device in the trough. The shapes of the charging hole 15 and the extraction hole 16 are made to approximately match the cross-sectional shape of the metal material to be plated.

In block B, after the aluminum tube l is suspended between the charging hole 15 and the withdrawal hole 16, when air is pressurized into the upper space 9 of the holding furnace 6 through the air introduction hole 14, the aluminum in the furnace is The molten metal surface of the alloy is pushed down, and the molten metal 7 rises in the stalk 10 and is pushed up into the trough 8. 2
0 is the bath of the hot-dip plating solution thus created, and the aluminum tubing l is completely immersed in it, or I! The outer surface is plated with an aluminum alloy. The rise in the level of the molten plating solution can be detected using the level detection bag 7I18.
After maintaining the hot water level for a predetermined period of time, air is removed from the air introduction hole 14, and one cycle of the hot-dip plating process is completed. In this case, this cycle may be repeated several times to further increase the plating thickness.

The aluminum tube material l that has been hot-dip plated in this way is pulled out from the trough 8 by the carrier device of the C block. 21 is an air knife that blows off excess plating liquid adhering to the aluminum tube material 1, and 22 is a carrier for the aluminum 9A tube material.

The aluminum tube material (2) is conveyed to the left along the track 24 while holding the tip portion (la) of the aluminum tube material (1) between the holding portions 23 of the carrier. 25 is a support roller made of aluminum tube material, 26.27
is the supporting leg.

FIG. 2 is a plan view of block B in FIG.
8 is a furnace cover, 29 is a support furnace hot water supply 12. 30 is an immersion tube assembled in the holding furnace, and a heating element 31 is inserted inside the tube, thereby heating the molten metal 7 in the holding furnace 6. and maintain it in a molten state.

In the figure, the same symbols as in FIG. 1 mean the same things.

In the present invention, the structure of the furnace wall 32 of the holding furnace 6 is not particularly limited as long as it has heat retention and heat insulation properties.For example, as shown in the cross-sectional view of FIG.
It is preferable to use ceramic wool 32d on the outside of the furnace Pi 32c.

In the above embodiment, a plurality of aluminum tubes may be charged into the trough in parallel so that they can be hot-dip plated at the same time.

In the present invention, the furnace pressure control circuit in the holding furnace 6 itself controls the inflow and outflow of air holes in response to the molten metal detection device in the trough 8.
The third item can be anything as long as it can be matched.
The figure is an explanatory diagram showing an example of such a furnace pressure control circuit.

In the figure, air introduced from a compressed air source opens a solenoid valve 33, closes a diaphragm valve 35 via a solenoid valve 34, and
It is introduced into the air inlet 14 of the holding furnace to increase the furnace pressure in the holding furnace 6 and push the molten metal 7 up through the stalk 10 into the trough 8. On the other hand, when the raised hot water level is detected by 18a, the solenoid valve 33 is closed to stop the compressed air, and when the hot water level falls and L8b is detected, the solenoid valve 33 is opened and the compressed air is sent into the holding furnace 6. This operation is repeated. , the molten metal 7 remaining in the trough 8 after the plating process on the metal material, which controls the position of the molten metal, closes the ZM valve 33 and opens the diaphragm valve 35 via the solenoid valve 34 to control the position of the holding furnace 6. By setting the internal pressure to atmospheric pressure, it flows out into the holding furnace 6 through the stalk 10. Note that in FIG. 3, the same symbols as in FIG. 1 mean the same things.

The hot-dip plating device 1 of the present invention uses an aluminum material having a higher melting point than the molten metal as the metal material to be plated, or an aluminum-silicon alloy, an aluminum-silicon-zinc alloy, or an aluminum-silicon-magnesium alloy as the molten metal. However, the application is not limited to this, and can be used to plate various metal materials with various molten metals.

Such metal materials include pure Al (AA1050.1
100, etc.) Ai-Mn system (AA3003.3105, etc.), Hemi-Cu system (Ai-0,5Cu, etc., numerical value 0.
5 is ball amount%. (same below), Al-Mg-5i system (
AA6063.6951 etc.), A1 as molten metal
-10Si, Al-10S i -1,5Mg, Al
-1O5i-3Zn, etc., and it is particularly preferable to combine molten metals (including alloys) of the same type with the metal material.

Particularly preferably, the plating apparatus of the present invention has a melting point of 1 (3
Al-B ~13wt% on the outer surface of an extruded multi-hole tube made of aluminum or aluminum alloy at 0°C or higher
S i -0.4~3vt% Mg alloy brazing filler metal 30~
Used to manufacture multi-hole aluminum heat exchanger tubes coated to a thickness of 80IL.

There is no particular restriction on the shape of the metal material to which the device of the present invention is applied, and the device can be applied to various shapes such as pipes, bars, and plates.

Hot-dip plating may be performed with the metal material fixed in a trough, or may be performed while the metal material is moving from zone B to zone C at a constant speed.

In the case of aluminum material, this moving speed is 280~50tsya
/seC range, and the immersion time is preferably in the range of 5 to 30 seconds. Outside this range, if it is less than 5 seconds, uniform plating cannot be achieved, and if it exceeds 30 seconds, the aluminum material will melt into the plating bath. Therefore, the thickness of the aluminum material becomes thinner.

The temperature of the molten aluminum alloy is usually in the range of 600 to 630°C, and the aluminum material charged into the trough is preferably preheated to 200 to 500°C in the A zone. In this case, the preheating temperature exceeds 500°C. The aluminum material becomes soft, its strength is extremely reduced, and the aluminum material deforms when being moved, which is undesirable.

Below 200℃, when aluminum material is introduced into the plating bath,
This is because the temperature of the plating bath decreases and uniform plating becomes impossible.

In this manner, plating with a thickness of 10 to 504 m can be performed using the apparatus of the present invention.

Test Example Using the equipment shown in Figures 1 to 3, aluminum multi-hole tubes for heat exchangers (aluminum alloy composition: AfL-1, IMn
, 4 holes, [22mm x thickness 5mm) 300 in A zone
After preheating to ℃, the furnace pressure was increased and the molten aluminum alloy (All Sei A Bun-10S L-
1.5 Mg, 620° C.) was pushed up into the trough, held for 15 seconds, and then drawn out to C block to form a plating film with a thickness of 30 pm.

<Effects of the Invention> According to the apparatus of the present invention, plating is performed by controlling the level of the hot-dip plating solution using air pressure, and conditions such as hot-dip plating temperature and immersion time are stabilized, and metal materials can be coated. A uniform plating film can be formed and plated products with stable quality can be obtained.

The apparatus of the present invention performs hot-dip plating while being held in a trough, and is suitable as a plating apparatus capable of forming a plating film of any thickness on the surface of a long metal material.

Furthermore, the apparatus of the present invention has the advantage that by maintaining the material in the trough and repeatedly raising and lowering the molten plating solution, a thick plating film can be obtained by repeating immersion plating a predetermined number of times without changing the processing conditions. .

Furthermore, according to the apparatus of the present invention, hot-dip plating can be performed while moving in a trough, and the heating time and temperature of the metal material to be plated by the molten metal can be controlled, so that the melting point between the metal material and the hot-dip plating solution can be controlled. It can be applied to items where the metal materials are close to each other and where the metal material may be softened or dissolved by the hot-dip plating solution over time using conventional methods.

Furthermore, according to the plating apparatus of the present invention, a uniform plating film can be formed on the outer surface of a metal material having a complicated shape.

Further invention? According to the present invention, productivity can be significantly increased by continuous hot-dip plating of long materials, which were difficult to plate in the past.

Therefore, the plating apparatus of the present invention is particularly suitable as a plating apparatus for coating the outer surface of a large tube for an aluminum heat exchanger with a brazing material made of an aluminum alloy.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a sectional view illustrating a plating process using the plating apparatus of the present invention, FIG. 2 is a plan view of the plating apparatus, and FIG. 3 is a furnace of the plating apparatus. It is an explanatory view of a pressure control circuit. Explanation of symbols l...Aluminum tube material 2...Support roller 3...Preheating burner 6...Holding furnace 7...Molten aluminum alloy 8...Trough lO...Stoke 11...Communication Hole 14... Air introduction hole 15... Charging hole 16... Pull-out hole 18... Molten metal level detection device 20... Molten plating solution 22... Carrier 28... Furnace cover 29... ...Hot water inlet 30...Immersion pipe 31...Heating element 32...Furnace wall Patent applicant Furukawa Aluminum Industries Co., Ltd. Agent Patent attorney Ii 1) Toshizo Figure 2 Figure 3

Claims (1)

[Claims] Consisting of a molten metal holding furnace, a trough, and a communication path connecting the insides of the two, the molten metal in the holding furnace is pushed out into the trough using air pressure as the operating pressure, and the metal material placed in the trough is immersed in the molten plating solution of the molten metal. A plating device characterized in that it performs hot-dip plating.