JP3063931B2 - Manufacturing method of vapor-deposited Zn-plated steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for vapor-depositing and zinc-plating a steel material such as a steel plate or a steel strip which can be incorporated in a high-speed production line.

[0002]

2. Description of the Related Art When a steel sheet is subjected to vapor deposition Zn plating, an oxide film on the surface is reduced and removed by heating in a reducing gas atmosphere to activate the steel sheet surface. The activation treatment using a reducing gas requires a gas reduction furnace having a long furnace length when a continuous steel strip running at a high speed has a slow reduction reaction.
Therefore, manufacturing costs and equipment burdens increase.

In the activation treatment using a reducing gas, the surface of the steel sheet is heated to 200 ° C. immediately before vapor deposition in order to quickly activate the steel sheet surface by gas reduction and form a vapor-deposited plating layer having good adhesion. The above high temperature is maintained. The temperature of the steel sheet further rises due to the heat of condensation of the evaporated metal during vacuum evaporation. An increase in the temperature of the steel sheet adversely affects the deposition of the plated metal.

For example, when the temperature of a steel sheet is 2 by vacuum deposition of Zn.
Above 50 ° C., re-evaporation of the deposited Zn occurs. As a result, it is difficult to increase the amount of deposited Zn in the activation treatment using a reducing gas that requires the steel sheet temperature to be 200 ° C. or higher, which is unsuitable for manufacturing a thick Zn-plated steel sheet. there were.

As a means for activating the surface of a steel sheet without excessively increasing the temperature of the steel sheet, sputter etching is regarded as promising. Sputter etching using plasma has long been known as a pretreatment for general vacuum deposition, and the substrate surface is activated by sputter etching the substrate in a plasma of Ar or the like so that metals, ceramics, etc. Is deposited. Recently, an activation process by sputter etching using an ion beam instead of plasma has been performed.

[0006]

SUMMARY OF THE INVENTION In order to increase the etching rate in sputter etching using plasma, it is necessary to use high-density plasma. Therefore, a strong magnetic field must be applied to the plasma generation space.

[0007] However, the steel plate to be plated is usually a ferromagnetic material except for austenitic stainless steel. When a strong magnetic field is applied to a ferromagnetic steel plate, irregular movements such as flapping and suction occur in the running steel plate. As a result, the operation becomes unstable, and a good vapor-deposited plating layer cannot be formed.

That is, the strength of the applied magnetic field is restricted in order to suppress the magnetic influence on the steel sheet, and high-density plasma cannot be obtained. Therefore, at present, the sputter etching rate is low and the steel sheet surface cannot be activated at high speed. In this respect, the application to the high-speed line has the same problem as the activation treatment using the reducing gas.

On the other hand, the sputter etching method using an ion beam can perform high-speed processing as compared with the activation processing using a reducing gas or plasma, and is suitable for a continuous steel strip processing line running at high speed. . However, the ion beam irradiation apparatus requires a large ion source and a power supply as the ion beam etching processing speed increases, and the facility load becomes extremely large.

It is also conceivable that the temperature of the steel sheet at the time of vapor deposition is set higher, the surface layer to be etched is reduced by evaporating the adsorbate on the steel sheet surface, and the activation processing speed is increased. However, since the steel sheet is maintained at a high temperature, the evaporated Zn is re-evaporated, and a thick plating layer cannot be formed. In addition, the burden of equipment costs for high-temperature heating increases.

The present invention has been devised to solve such a problem.
Even if an Al deposition process is provided between the n deposition process and the ion beam etching treatment amount is reduced to increase productivity,
An object is to form a vapor-deposited Zn plating layer exhibiting good adhesion.

[0012]

In order to achieve the object, the present invention irradiates a steel material such as a steel plate, a steel strip or the like with a small irradiation dose to lightly activate the surface of the steel material at a temperature of 200 ° C. or less. After the conversion, A with an adhesion amount of 0.05 g / m ² or more
Then, a Zn plating layer having a predetermined adhesion amount is formed by vapor deposition. In the activation treatment by ion beam irradiation, it is not necessary to bring the surface of the steel material to be plated into a completely activated state. For example, as long as the adhesion of the deposited Al plating layer to the steel material surface is ensured, 0.002 coulomb / cm 2 It can be performed with a low dose of m ² or less.

When the steel material to be plated contains elements such as Si, Cr and Al which are more easily oxidized than Fe, the irradiation amount of the ion beam can be further reduced. For example, the lower limit of the irradiation amount can be reduced to 0.0008 coulomb / m ² for a steel sheet containing 0.4% by weight or more of Si. Si: 0.3% by weight or more and M
The lower limit of the irradiation amount can be reduced to 0.0006 coulomb / m ² for a steel sheet containing n: 0.5% by weight or more. Cr: 0.002 for a steel sheet containing 2% by weight or more.
Up to 08 coulomb / m ² , Cr content 11.5% by weight
As described above, the lower limit of the irradiation amount can be reduced to 0.00008 coulomb / m ² . For a steel sheet containing Al: 1.5% by weight or more, the lower limit of the irradiation amount can be reduced to 0.0008 coulomb / m ² .

[0014]

[Work] Al is a very active element. Therefore, even if a thick oxide film remains on the steel surface,
1 and the oxide film, a reaction occurs between the base steel and the oxide film.
A strong bond is obtained between the Al layers. As a result, evaporation A
The l-plated layer exhibits excellent adhesion to the underlying steel.
Therefore, as a pretreatment for the steel material to be plated, it is sufficient to remove only the fragile gas adsorbed layer such as H ₂ O and O ₂ and the fragile extreme surface layer of the oxide film on the surface. The gas adsorption layer has a very low bonding force to the underlying steel, and is easily removed by the ion beam etching action. The weak surface layer of the oxide film is also removed by light etching.

When a steel material contains easily oxidizable elements such as Si, Cr, and Al, the oxide film formed on the surface of the steel material is dense with oxides of these elements mixed. Therefore, even if this type of steel is left in the air, the fragile surface layer of the oxide film does not grow thickly, and H ₂ O, O
There are few gas adsorption layers such as ₂ . Therefore, when this kind of steel is etched with an ion beam, the irradiation amount of the ion beam can be set further lower. Also,
Mn coexisting with Si also has the effect of reducing the ion beam irradiation dose.

The deposited Al plating layer formed on the base steel has excellent adhesion to the base steel and has a highly active surface. Therefore, if the deposited Al plating layer is provided thereon without exposing the deposited Al plating layer to the outside air,
A strong bonding interface is formed between the Al plating layer and the Zn plating layer. As a result, a Zn plating layer having excellent adhesion is formed on the surface of the steel material. The deposition of Zn is performed without heating the steel material or while keeping the steel material temperature at 100 ° C. or less. This not only reduces the load on the equipment for heating the steel material, but also completely suppresses the re-evaporation of Zn, making it possible to form a thicker Zn plating layer.

The adhesion amount of the deposited Al plating layer applied to the base steel is set at 0.0 to improve the adhesion of the deposited Zn plating layer.
It is necessary to be 5 g / m ² or more. 0.05g /
When the adhesion amount is less than m ^2, the coating effect of the deposited Al plating layer on the base steel is insufficient, and the oxide film formed on the steel material surface affects the deposited Zn plating layer,
It reduces the adhesion of the plating layer. 0.05g /
When it is more than m ² , the above-mentioned effect of the deposited Al plating layer is remarkably exhibited, and a deposited Zn plating layer having excellent adhesion even with light ion beam etching is formed.

By using the deposited Al plating layer as the first layer, the irradiation amount of the ion beam is greatly reduced. Therefore, not only the ion source and the power source can be reduced in size and the facility load can be reduced, but also high-speed processing can be performed. That is, it is possible to increase the passing speed of a strip steel or the like as a material to be plated and improve productivity.

It is to be noted that a vapor-deposited Al plating layer having good adhesion can be formed only by heating the steel material after degreasing and pickling in a vacuum. Then, without exposing the steel material to the atmosphere, Z is deposited on the active deposited Al plating layer as deposited.
When n is deposited, the adhesion of the deposited Zn plating layer can be improved. However, in this method, two steel materials are used to secure the adhesion between the deposited Al plating layer and the base steel.
Heating to a high temperature of 00 ° C. or higher is required, and the amount of deposited Zn cannot be increased due to re-evaporation. In addition, the equipment load for heating the steel material also increases, which causes an increase in manufacturing cost.

[0020]

EXAMPLE As a material to be plated, three types of steel sheets having the following compositions were used. (1) Steel sheet with varied Si content and Mn content Si: 0.008 to 1.45% by weight, Mn: 0.09 to
1.58% by weight, C: 0.04 to 0.05% by weight, P:
0.012-0.019% by weight, S: 0.010-0.
018% by weight, Cr: 0.016 to 0.041% by weight,
Al: 0.046 to 0.068% by weight, balance Fe and inevitable impurities

(2) Steel sheet with varied Cr content Cr: 0.004 to 19.65% by weight, C: 0.03 to
0.05% by weight, P: 0.02 to 0.026% by weight,
S: 0.031 to 0.042% by weight, Si: 0.01 to
0.05% by weight, Mn: 0.13 to 0.20% by weight, A
l: 0.033 to 0.058% by weight, balance Fe and unavoidable impurities

(3) Steel sheet with varied Al content: Al: 0.024 to 3.95% by weight, C: 0.03 to
0.05% by weight, P: 0.021 to 0.025% by weight,
S: 0.031 to 0.046% by weight, Si: 0.02 to
0.03% by weight, Mn: 0.11 to 0.18% by weight, C
r: 0.012 to 0.033% by weight, balance Fe and inevitable impurities

As the continuous vapor deposition apparatus, an apparatus having the equipment configuration schematically shown in FIG. 1 was used. The steel strip 10 as the material to be plated is sent out from the payoff reel 11, and the deflector rolls 12 and 13 and the entrance-side vacuum sealing device 20
Through the vacuum chamber 30. Inlet side vacuum sealing device 2
0 has a large number of seal rolls 21, 22,..., And the space between the seal rolls is gradually reduced in pressure.

The vacuum chamber 30 is evacuated by vacuum pumps 31 and 32 and kept in a reduced pressure atmosphere. Vacuum chamber 3
0, the ion beam irradiation device 40, the Al vapor deposition device 50, and the Zn vapor deposition device 6 are arranged along the transport direction of the steel strip 10.
0 is arranged. Ion beam irradiation device 40, Al
Conventional equipment is used as the vapor deposition device 50 and the Zn vapor deposition device 60.

The surface of the steel strip 10 is irradiated with the Ar ion beam 41 emitted from the ion beam irradiation device 40, and the surface of the steel strip 10 running in the vacuum chamber 30 is activated. On the surface of the activated steel strip 10, an Al vapor deposition device 50
Al evaporated from the Al source 51 is deposited. Then, Z
Zn evaporated from the Zn source 61 of the n vapor deposition device 60 is deposited on the Al plating layer to form a deposited Zn plating layer.

The steel strip 10 on which Zn has been vapor-deposited is taken up on a take-up reel 14 through a delivery side vacuum sealing device 70.
The outlet-side vacuum seal device 70 also includes a plurality of seal rolls 71, 72,... Like the inlet-side vacuum seal device 20, and the space between the seal rolls is stepwise increased in pressure toward the outlet side. I have.

Ion beam etching, Al deposition and Z
The n deposition was performed under the conditions shown in Table 1. In addition, the steel strip temperature before vapor deposition was kept at 50 ° C. or less, and the steel strip was not heated.

[0028]

[Table 1]

The amount of ion beam etching, that is, the quantity of electricity of Ar ions per unit area to be irradiated is determined by the quantity of electricity of Ar ions neutralized before reaching the steel strip from the ion source (ion beam irradiation device 40). The amount and the electric quantity of Ar ions reaching the steel strip as ions were expressed as the sum. That is, it is the measured amount of Ar ions assuming that the ions irradiated from the ion source are not neutralized at all.

In each of the following examples, a test piece was cut out from a steel strip plated with vapor-deposited Zn, and the test piece was bent so as to be completely adhered by 180 ° bending, and an adhesive tape was attached to the bent portion. Then, the adhesiveness of the deposited Zn plating layer was examined by peeling off the adhesive tape. And the thing which has not peeled at all in the vapor deposition Zn plating layer after peeling off an adhesive tape was evaluated as having favorable adhesiveness.

Example 1 A steel strip having the following composition was used as a material to be plated, and the relationship between the amount of deposited Al and the amount of ion beam etching to obtain a deposited Zn plating layer having excellent adhesion was determined. investigated.

C: 0.03% by weight, Si: 0.008% by weight, Mn: 0.11% by weight, Cr: 0.024% by weight, Al: 0.045% by weight, P: 0.011% by weight ,
S: 0.011% by weight, balance Fe and inevitable impurities

FIG. 2 shows the results of the investigation. As is clear from FIG. 2, when the Al adhesion amount becomes 0.05 g / m ² or more,
It can be seen that the beam irradiation amount during ion beam etching, which is necessary for forming a vapor-deposited Zn plating layer having excellent adhesion, is greatly reduced. And 0.002 coulomb /
With an irradiation amount of m ² or more, a deposited Zn plating layer having excellent adhesion is formed.

On the other hand, the Al adhesion amount is 0.05 g / m
^If it is less than ² , it is necessary to increase the irradiation amount of the ion beam in order to improve the adhesion of the deposited Zn plating layer. In particular, at an Al adhesion amount of 0.02 g / m ² or less,
Unless the irradiation amount was 0.10 coulomb / m ² or more, no improvement in adhesion of the deposited Zn plating layer was observed.

Example 2: A steel strip (M) of the above-mentioned steel type (1)
(n content: 0.09 to 0.12% by weight) was used as a material to be plated, and Al was deposited at an adhesion amount of 0.06 g / m ² , and then a deposited Zn plating layer was formed. And S of steel strip
The relationship between the i content and the ion beam etching treatment amount at which good adhesion was obtained was investigated.

As is apparent from FIG. 3 showing the results of the investigation, when the Si content of the steel strip is 0.4% by weight or more, the ion beam necessary for forming a vapor-deposited Zn plating layer having good adhesion is obtained. It can be seen that the irradiation amount has decreased. Then, a deposited Zn plating layer having excellent adhesion is formed by ion beam etching at a dose of 0.0008 coulomb / m ² . On the other hand, in a steel strip having a Si content of less than 0.4% by weight, an improvement in adhesion is observed only at an irradiation amount of 0.002 coulomb / m ² or more.

Example 3: A steel strip (M) of the above-mentioned steel type (1)
(n content: 0.45 to 0.54% by weight) was used as a material to be plated, and Al was deposited at an adhesion amount of 0.06 g / m ² to form a deposited Zn plating layer. And S of steel strip
The relationship between the i content and the ion beam etching treatment amount at which good adhesion was obtained was investigated.

As is apparent from FIG. 4 showing the results of the investigation, when the Si content of the steel strip is 0.3% by weight or more, the ion beam necessary for forming a vapor-deposited Zn plating layer having good adhesion is obtained. It can be seen that the irradiation amount has decreased. Then, a deposited Zn plating layer having excellent adhesion is formed by ion beam etching at a dose of 0.0006 coulomb / m ² .

From the comparison between FIG. 3 and FIG. 4, it can be seen that the required dose is reduced by the inclusion of Mn. Further, M
FIG. 5 shows a steel strip in which the n content was increased to 1.5 to 1.58% by weight and a deposited Zn plating layer was similarly formed on the steel strip.
As shown in the figure, the same tendency as that of the steel strip having Mn of 0.45 to 0.5% by weight is shown.

Example 4: A steel strip of the above-mentioned steel type (2) was used as a material to be plated, and A was applied at an adhesion amount of 0.06 g / m ² .
After vapor deposition of 1, a vapor-deposited Zn plating layer was formed. Then, the relationship between the Cr content of the steel strip and the amount of ion beam etching treatment at which good adhesion was obtained was investigated.

FIG. 6 shows the results of the investigation. As is clear from FIG. 6, when the Cr content of the steel strip is 2% by weight or more,
It can be seen that the irradiation amount of the ion beam required to form a vapor-deposited Zn plating layer having good adhesion is reduced. Then, in a region where the Cr content is less than 11.5% by weight, a deposited Zn plating layer having excellent adhesion is formed by ion beam etching at a dose of 0.0008 coulomb / m ² . Further, when the Cr content is 11.5% by weight or more, a vapor-deposited Zn plating layer having excellent adhesion is formed by ion beam etching at an irradiation amount of 0.00008 coulomb / m ² .

On the other hand, in a steel strip having a Cr content of less than 2% by weight, the effect of the Cr content did not appear, and the irradiation dose was 0.0%.
For the first time, an improvement in adhesion is observed at an irradiation dose of 02 coulombs / m ² or more.

Example 5: A steel strip of the above-mentioned steel type (3) was used as a material to be plated, and A was applied at an adhesion of 0.06 g / m ² .
After vapor deposition of 1, a vapor-deposited Zn plating layer was formed. Then, the relationship between the Al content of the steel strip and the amount of the ion beam etching treatment at which good adhesion was obtained was investigated.

As is clear from FIG. 7 showing the results of the investigation, when the Al content of the steel strip is 1.5% by weight or more, the ion beam necessary for forming a vapor-deposited Zn plating layer having good adhesion is obtained. It can be seen that the irradiation amount has decreased. Then, a deposited Zn plating layer having excellent adhesion is formed by ion beam etching at a dose of 0.0008 coulomb / m ² . On the other hand, in a steel strip having an Al content of less than 1.5% by weight, the effect of the Al content did not appear, and an irradiation amount of 0.002 coulomb / m ² or more was required for improving the adhesion.

[0045]

As described above, according to the present invention, a steel material lightly activated by ion beam irradiation is made of Al
Is deposited to form a deposited Zn plating layer. The deposited Al plating layer formed in advance is bonded to the underlying steel with sufficiently good adhesion because the activity of Al is high even if some oxide film is present on the surface of the steel material. Moreover, since Zn is deposited on the active surface of the deposited Al plating layer, the formed deposited Zn plating layer exhibits excellent adhesion.

Since the effect of the oxide film on the surface of the base steel is suppressed by the deposition of Al, the surface activation by ion beam etching can be performed with a small amount of ion beam irradiation. Therefore, evaporation Zn suitable for high-speed production line
It is a plating method. Further, since the steel material is not heated to a high temperature, a brittle intermetallic compound such as Fe-Al is not formed, and the obtained vapor-deposited Zn-plated steel sheet does not impair the original mechanical properties of the base steel. It is a material excellent in workability.

[Brief description of the drawings]

FIG. 1 shows a continuous Zn deposition apparatus used in an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the amount of Al deposition and the amount of ion beam irradiation on the adhesion of a deposited Zn plating layer.

FIG. 3 shows S of a steel material giving the adhesion of a deposited Zn plating layer.
Graph showing the relationship between i content and ion beam irradiation dose

FIG. 4 S of steel material giving adhesion to deposited Zn plating layer
Graph showing the relationship between i, Mn content and ion beam irradiation dose

FIG. 5: S of steel material giving adhesion to deposited Zn plating layer
Graph showing the relationship between i, Mn content and ion beam irradiation dose

[Fig. 6] C of steel material giving adhesion to vapor deposited Zn plating layer
Graph showing the relationship between the r content and the ion beam irradiation dose

[Fig. 7] Fig. 7 shows A of a steel material giving the adhesion of a deposited Zn plating layer.
Graph showing the relationship between the l content and the ion beam irradiation dose

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Steel strip 30 Vacuum chamber 40 Ion beam irradiation apparatus 50 Al vapor deposition apparatus 60 Zn vapor deposition apparatus

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C23F 4/00

Claims (1)

(57) [Claims] 1. The surface of a steel material is exposed to 200
After slight etching at a temperature of less than
A method for producing a vapor-deposited Zn-plated steel material, comprising vapor-depositing Al at 5 g / m ² or more, and then vapor-depositing Zn without exposing to outside air.