JPH04173959A - Production of metallic sheet plated with al alloy by vapor deposition - Google Patents

Abstract

PURPOSE:To form a uniform vapor-deposited layer of an Al alloy having no change in the compsn. in the thickness direction on the underside of travelling band steel by alternately arranging vessels for evaporating Al and vessels for evaporating an alloying element under the band steel and vapor-depositing Al and the alloying element on the underside of the band steel. CONSTITUTION:Vessels 2a, 2c for evaporating Al and vessels 2b, 2d for evaporating an alloying element such as Ti are alternately arranged under band steel 1 travelling in the direction of an arrow A and the vessels 2a, 2c and 2b, 2d are separetely heated to evaporate Al and Ti. Though Al and Ti are different from each other in vapor pressure, Al-Ti mixed vapor having a prescribed compsn. is generated by regulating heating conditions and a uniform vapor- deposited layer of an Al alloy having a constant mixing ratio between Al and Ti in the thickness direction is formed on the underside of the band steel 1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an improvement in a method for manufacturing an Al alloy plated metal plate by a vapor deposition method, and in particular, when forming an Al alloy plated layer on a metal plate. The present invention relates to a method for reducing non-uniformity of the plating composition in the thickness direction of the Al alloy plating layer so as to obtain a vapor deposited Al alloy plating layer having as uniform a composition as possible.

In addition, the present invention targets various metal plates by applying A by a vapor deposition method.
The type of metal plate is not particularly limited as long as it can be subjected to l-alloy plating treatment, but in this specification, the description will focus mainly on vapor-deposited Al alloy-plated steel sheets, which have recently attracted particular attention.

[Prior art] Al alloy plated steel sheets are excellent in heat resistance, corrosion resistance, formability, heat reflection, aesthetics, etc., and are relatively inexpensive to produce, so they are used in automobile exhaust systems. It is widely used for parts, incinerator parts, parts for various household electrical appliances, building materials, etc.

Among these, vapor-deposited Al alloy plating, which combines Al with alloying components such as Cr, Ti, Zn, and Cu, is useful because it is possible to provide properties depending on the application by changing the type and content of the alloying elements. , the demand for which has recently increased significantly.

Hot-dip plating has been mainly used as the Al alloy plating method, but recently, a vacuum evaporation method has been developed in which vapors of AI and alloying elements are supplied to the lower surface of the steel strip while it is continuously running, and the vapor is deposited on the surface of the steel strip. As it was developed (Japanese Unexamined Patent Publication No. 1983
No. 21060, No. 64-28359, etc.), it is attracting attention partly because the alloy composition can be easily adjusted and it can be produced continuously.

By the way, the most important problem when performing vapor-deposited Al alloy plating is the uniformity of the Al alloy plating layer in the thickness direction. For example, FIG. 3 is a conceptual diagram showing a conventional vapor-deposited Al alloy cleaning method, in which metal evaporators 2a and 2b are placed below a steel strip 1 that is continuously running in the direction of arrow A, and metal evaporators 2a and 2b are placed in the direction of travel of the steel strip 1. One evaporation tank 2a is charged with Al, and the other evaporation tank 2b is filled with alloying elements (hereinafter referred to as alloying elements: Ti, Cr, Cu, Ni).

In addition to elements such as Zn, Fe, and Si, Al2O3 and Sin
(hereinafter represented by Ti) is charged and heated and evaporated by an electron beam or the like (not shown), and these vapors are deposited on the lower surface side of the strip steel plate 1. At this time, as is clear from FIG. 3, the strip steel plate 1 is first coated with Al! #German or Al-rich vapor is deposited, then a mixed vapor of AI and T1 is vaporized, and finally Ti1l-rich or Ti-rich vapor is vapor deposited, and the alloy composition of the deposited layer is determined in the thickness direction. This results in non-uniformity. In this way, the alloy composition of the plating layer gradually changes, depending on the use and purpose.
In some cases, it is preferred as a functionally graded material, but in many cases, for boat fishing, a plated material with a uniform alloy composition in the thickness direction is desired.

Therefore, as shown in Fig. 4, one evaporation tank 2 contains Al and Ti.
It was also considered to charge and heat evaporate at the same time, but
This method causes the following problems. That is, since the equilibrium vapor pressures of Al and Ti are different, it is difficult to keep the alloy bath composition and the vapor composition the same. For example, Ti has a lower equilibrium vapor pressure than Al, so the Ti content in the mixed vapor is lower than the Ti content in the alloy, and initially a relatively large amount of Al evaporates, making the vapor composition rich in Al. However, as the treatment time passes and the Al content of the plating bath decreases, the Ti content in the steam gradually increases. Therefore, in order to keep the vapor composition, that is, the plating composition constant, the alloy bath composition and bath temperature must always be kept constant, and control to keep the vapor composition constant is by no means easy. These problems become even more noticeable when performing multi-component alloy polishing of three or more components.

In addition, if AI is used alone, the vapor deposition process can be carried out without any problems by using an evaporator made of ceramics such as alumina, but if Ti is charged together with AI into a ceramic evaporator and heated, the evaporator structure will be Oxygen and Mg in the refractory material are reduced and eroded by molten Ti.
, Ca.

Not only do Si and the like get mixed into the steam and change the melting point and viscosity, but these impurity elements also get mixed into the steam, degrading the quality of the cleaning layer. Therefore, water-cooled evaporation tanks made of copper are used to withstand both alloying components such as Al and Ti, but in evaporation tanks with a water-cooled structure, most of the heat added for evaporation is absorbed by the evaporation tank. As a result, thermal efficiency becomes extremely poor.

[Problems to be Solved by the Invention] The present invention has been made with attention to the above-mentioned circumstances, and its purpose is to form an Al alloy plating on a metal plate by vapor deposition, in which AI and an alloying element are combined. By adopting a method of heating and evaporating the water in separate evaporation tanks, it is possible to eliminate the difficulty required to control the bath composition, solve problems such as erosion of the evaporation tank constituent materials, and evaporate from the individual evaporation tanks. The present invention aims to provide a method that can reduce the non-uniformity in the thickness direction of the plating layer caused by the method and obtain a vapor-deposited Al alloy plated metal plate having a uniform alloy composition.

[Means for Solving the Problems] The structure of the manufacturing method according to the present invention that can solve the above problems is that evaporation tanks for Al and alloying elements are provided below the running belt-shaped metal plate. Placed along the running direction,
Evaporated Al is mixed and deposited on the lower surface of the strip-shaped metal plate to form a vapor-deposited Al alloy plating layer with evaporated substances from each evaporation tank.
In the method for manufacturing alloy plated metal sheets, at least one of Al and the alloying element is stored separately in two or more evaporation tanks, and the evaporation tank for Al or the alloying element is separated by the evaporation tank for the other alloying element or AI. The purpose is to reduce the non-uniformity of the plating composition in the Al alloy plating layer in the thickness direction by arranging the aluminum alloy plating layer.

[Function] Hereinafter, the structure and effects of the present invention will be specifically explained with reference to the drawings, mainly focusing on the case where a steel plate is coated with an alloy vapor deposition of Al and Ti.

FIG. 1 is a conceptual diagram showing the most basic configuration according to the present invention, in which three evaporation tanks 2a are arranged below the steel strip 1 running in the direction of arrow A along the running direction of the steel strip 1. , 2b,
2c are placed adjacent to each other, and evaporation is carried out [2b is charged with Ti and the evaporation tank 2a is placed.

Charge AI to 2c. Then, the metal in each evaporation tank is heated and evaporated by a heating source (such as an electron beam) not shown. Note that the evaporation atmosphere is maintained at a high vacuum state as in the conventional vapor deposition plating method.

With this method, as is clear from Figure 1, the initial layer and the outermost layer of the vapor-deposited Al alloy plating layer will be rich in AI, but the intermediate layer will be an alloy in which Al and T1 are almost uniformly vapor-deposited. It becomes a plating layer. Moreover, by selecting and using a corrosion-resistant material according to the metal to be charged in each of the evaporation tanks 2a to 2C, corrosion of the evaporation tank can be effectively suppressed, and there is also a risk that impurities may be mixed into the vapor-deposited plating layer. It disappears. Also, Al
The amount of evaporation of Ti can be arbitrarily changed by adjusting the thermal energy applied to each evaporation tank 2a to 2c by an electron beam or the like, so the properties required for the plating layer (corrosion resistance, gloss, It is possible to obtain a plating layer with a desired composition depending on the processability, etc.).

FIG. 2 shows another embodiment of the present invention, in which evaporation tanks 2a to 2d arranged along the running direction of the strip steel plate 1,
The structure is substantially the same as the example shown in FIG. 1, except that AI and Ti are alternately charged and heated to evaporate.

In Fig. 1.2, the case was explained in which alloy plating is made of two metal elements (AI and Ti), but when Al and other alloying components (such as Cr, Cu, Ni, Zn, F
In the case of forming an alloy layer consisting of Al, SL, etc.), the above method can be carried out in the same manner. If this method is used, ceramics such as Al2O3 and 5i02 can be used in combination with Al in addition to metals. It is also possible to obtain composite AI plating.

In short, in the present invention, when performing vapor-deposited Al alloy plating consisting of AI and one or more alloying elements,
and alloying element are evaporated from separate evaporation tanks, and at least one of AI and alloying element is stored separately in two or more evaporation tanks, and is separated by the evaporation tank of the other alloying element or AI. evaporated Al
Alloy plating is performed. Then, by overlapping the evaporation regions of AI and alloying elements with each other and mixing them on the lower surface side of the strip metal plate, the evaporated Al
It is characterized by reducing the non-uniformity of the composition in the thickness direction of the alloy plating layer. Therefore, as long as these characteristics can be effectively utilized, there are no restrictions on the type or number of alloying elements that can be combined with Al, or the type of metal strip, and the heat source for evaporation can also be resistance heating, in addition to electron beam heating. High frequency heating, laser beam heating, etc. can be used. In addition, in the present invention, the vapor deposition plating method refers to a vapor deposition plating method in a broad sense, and ion blating methods, sputtering methods, CVD methods, etc. are all included in the scope of vapor deposition plating methods employed in the present invention. It can be done.

[Example 1] The arrangement of the evaporation tanks 2a to 2c shown in FIG. 1 was adopted, and a vapor-deposited Al--Cr alloy plated steel sheet was manufactured under the following conditions.

(Experimental conditions) Material to be plated: Ferritic stainless steel "I" (SUS
4101)... After alkaline electrolytic degreasing, the surface is activated by heating with electron beam irradiation and Ar ion bombardment in vacuum, preheating temperature is 350 to 400°C Evaporation tanks 2a to 2c: All alumina -Uses one made of silica-based ceramics.

Evaporation raw material = Cr is charged into 2a and 2c, and Al is charged into 2b.

Heating method: Using a piercing type electron gun (maximum output 300kW), polarization of the electron beam by a magnetic field, scanning on the surface of the evaporation raw material, and jumping between evaporation tanks were performed.

Distance between plated material and evaporation tank, vertical distance 350 to 500
mm Vacuum degree of vapor deposition chamber: Approximately 1O-2Pa Plating deposition amount: Approximately 20 g/m2 Plating composition: 85%Al-15%Cr When the alloy composition in the thickness direction of the obtained vapor-deposited plating layer was investigated, it was found that the alloy The composition is almost uniform in the thickness direction, and Al. 3
It was confirmed that the Cr2 intermetallic compound phase and the Al phase were uniformly dispersed.

Example 2 The arrangement of the evaporation tanks 2a to 2d shown in FIG. 2 was adopted, and a vapor-deposited Al-Zn alloy plated steel sheet was manufactured under the following conditions.

(Experimental conditions) Material to be plated: Same as in Example 1.

Evaporation tank: 2a, 2c... Made of alumina-silica ceramics, 2b, 2d... Made of graphite, Evaporation raw material + Inside 2a, 2c... Al Inside 2b, 2d... Zn Heating method ・2 electrons Gun (pierce type, maximum output 300
kw) are placed in front and behind the copper strip in the traveling direction with the evaporator groups 2a to 2d in between, and one electron gun is used to collect Al and Zn in the evaporators 2a and 2b, and the other electron gun is used to Heat Al and Zn in 2c and 2d.

Distance/vertical distance between plated material and evaporation tank: 350 to 500
mDI Deposition chamber vacuum degree: Approximately 1O-2Pa Plating deposition amount: Approximately 40 g/m2 Plating composition = 50% Al-50% Zn When the alloy composition in the thickness direction of the obtained vapor-deposited plating layer was investigated, it was found that It was confirmed that the plated layer had a uniform Al and Zn profile, and the α-AI rich phase and the β-Zn rich phase were uniformly mixed.

[Effects of the Invention] The present invention is configured as described above, and although it is a method of evaporating Al and alloy elements from separate evaporation tanks, compositional non-uniformity in the thickness direction of the vapor-deposited Al alloy plating layer is avoided. As a result, it has become possible to significantly reduce the amount of stress, and to efficiently produce vapor-deposited Al alloy-plated metal plates of uniform and stable quality with excellent productivity. Moreover, since the present invention uses a method in which Al and alloying elements are heated and evaporated in separate evaporation tanks, the plating composition can be freely changed by adjusting the amount of heat to each evaporation tank and changing the amount of evaporation. , it is possible to obtain an Al alloy plated material with performance suitable for the application and purpose.

[Brief explanation of the drawing]

Fig. 1.2 is a conceptual diagram showing an embodiment of the present invention, and Fig. 3.4 is a conceptual diagram showing a conventional example.

Claims (1)

[Claims] Each evaporation tank for Al and alloying elements is arranged below the running metal strip along the running direction of the metal strip, and the evaporated matter from each evaporation tank is mixed on the lower surface of the metal strip. In a method for producing a vapor-deposited Al alloy plated metal plate in which a vapor-deposited Al alloy plating layer is formed, at least one of Al and the alloy element is stored separately in two or more evaporation tanks, and the evaporation tank for Al or the alloy element is stored in the other. A method for producing a vapor-deposited Al alloy plated metal sheet, characterized in that non-uniformity of the plating composition in the thickness direction of the Al alloy plated layer is reduced by arranging the plate so as to be separated by an evaporation tank of alloying elements or Al. .