JPS5983765A - Manufacture of vacuum deposited galvanized steel sheet efficient in adhesion of plated metal - Google Patents

Abstract

PURPOSE:To manufacture vacuum deposited galvanized steel sheet efficient in adhesion of plated metal, by a method wherein the cleaned surface of steel sheet is processed with the vacuum deposition of zinc by making the vacuum pressure of the atmosphere and the base sheet temperature at vacuum deposition conform to specified conditions. CONSTITUTION:The surface of steel sheet is continuously cleaned with reduction by its heat treatment at 650-900 deg.C in a reducing atmosphere containing hydrogen. Then, this cleaned surface is continuously processed with vacuum deposition of zinc under conditions conforming to the relations as shown in the formula (25logP+163<=T<=300) by making the atmospheric vacuum pressure P(Torr) and the base sheet temperature of vacuum deposition T( deg.C). Thus, the zinc plating shows minute uneveness composed of fine zine crystals on its surface and has efficient film adhesion properties.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a vacuum-deposited galvanized steel sheet with excellent plating adhesion. In a preferred embodiment of the present invention, in addition to excellent tamping adhesion.

Vacuum deposition with excellent coating adhesion! An IF lead-plated steel sheet is obtained.

In recent years, galvanized steel sheets coated with zinc or aluminum on one side have been used in automobiles, electrical equipment, etc. Methods for manufacturing single-sided plated copper plates include a method in which both sides are hot-dipped and then only one side is polished away, and a method in which only one side is plated by electroplating. However, in the former method, there are problems such as wastage of materials and energy for removing the abrasive particles at low production speeds, and difficulty in maintaining the equipment for this purpose. Furthermore, in the latter case, if a thick plating layer is to be obtained, there are problems such as low production speed.

On the other hand, there is a method of manufacturing a single-sided plated copper plate, which uses vacuum deposition, which solves one or more of the manufacturing problems. This method can plate only one side at high speed, does not require equipment for polishing and removing the plating layer, and has the feature of being able to plate thin to thick plating layers at high speed. It is much better than the previous method.

However, the manufacturing of vacuum-deposited galvanized steel sheets is currently difficult due to the lack of accumulated research on equipment and technology.

Very few have been put to practical use industrially. For this reason,
There are few reports regarding the adhesion of the plating layer on vacuum-deposited galvanized steel sheets.

Therefore, in order to take advantage of the above-mentioned characteristics of vacuum evaporation plating, the present inventor conducted various experiments regarding the manufacturing conditions of vacuum evaporation galvanized steel sheets and the adhesion of the plating layer to the steel sheet. By setting the substrate temperature and the vacuum pressure of the atmosphere to appropriate conditions, the coating film adhesion can be improved depending on the conditions under which the plating adhesion was excellent. We discovered that vacuum-deposited galvanized steel sheets can be replaced.

In other words, in the present invention, the vacuum pressure of the atmosphere during vacuum evaporation is set to P
(Torr) and the substrate temperature during vapor deposition is TmQ.

The present invention is comprised of a method for producing a vacuum-deposited galvanized steel sheet with excellent plating adhesion, characterized by performing deposition under the following conditions: 25jogP+166<T<100.

If the method of the present invention is carried out under the condition of 25 og P + 165 < T < 200, the vacuum deposited galvanized steel sheet not only has excellent plating adhesion but also has excellent adhesion of the coating film applied to its surface. is obtained.

The invention is carried out as follows.

Prior to vapor deposition, the surface of the steel plate is first cleaned.

To do this, the surface of the steel sheet is degreased by electrolytic cleaning or oxidation in a furnace, and then the steel sheet is heated to a temperature of 650 to 900°C in an atmosphere of hydrogen or a mixed gas of hydrogen and nitrogen to reduce and remove oxides on the surface of the steel sheet. hand.

After cleaning the surface of the steel plate by activating it or irradiating it with an electron beam, the steel plate is introduced into a vacuum deposition chamber and heated under a vacuum atmosphere of 1 T<>rr or less, preferably 10-1 T.
Zinc evaporation is performed below orr. In this case, the substrate temperature T during vapor deposition and the vacuum pressure P (Torr) of the atmosphere meet the conditions 25j
This must be done within a range that satisfies ogP+163<T<300.

When the substrate temperature exceeds 300''C, the zinc adhering to the steel plate evaporates from the surface of the steel plate, or reevaporates.

Although the adhesion of the plating layer is good, the plating thickness becomes thinner, resulting in a decrease in production speed in industrial production. On the other hand, the substrate temperature is C254ngP(Tnrr)-1-165
) ("C;), the adhesion between the plating layer and the steel plate will deteriorate.
If you are looking for a lead-plated steel plate, 25. AogP+'I6
It must be carried out under the conditions of 5≦T≦200.

In this case, when the substrate temperature is below 200'''C, the surface of the deposited silver plating is composed of fine zinc crystals and exhibits dense irregularities, and has excellent coating film adhesion, but when the substrate temperature is 1i
As the value increases, the 9-plated surface becomes a relatively smooth surface made of large crystals. For this reason, when the substrate temperature exceeds 200° C., the adhesion of the coating film deteriorates.

As the zinc used in the present invention, zinc ingots (for example, JIS H2107 (class 2)) used in the production of ordinary hot-dip galvanizing and electrogalvanizing are sufficient.

A first example of an apparatus for carrying out the method of the present invention and its operation is described below.
As shown in the figure. The steel strip 2 that has come out of the unwinding reel 1 is heated in a non-oxidizing furnace or an oxidizing furnace 6 to remove oil adhering to the surface, and then in a hydrogen-containing reducing furnace 4 where the surface is reduced and activated, and at the same time, the copper strip is Annealing is performed, and then the temperature is adjusted to a temperature suitable for vapor deposition in a cooling furnace 5. Next, the steel strip 2 is inserted into the entrance sealing furnace 6 which has a plurality of sealing rolls 7 . It passes through a deflector roll 8 and is guided into a deposition chamber 9. Here, the vacuum pressure is lowered stepwise in the entrance sealed furnace, and the target vacuum pressure is obtained in the deposition chamber 9. In the evaporation chamber 9, the zinc in the evaporation pan 18 heated by the heater 11 becomes vapor, and the chamber 10
passed through and plated onto the copper strip. Here, the molten zinc 15 in the melting furnace 1 is sucked up into the evaporation pot 1B through the snorkel 12 due to the pressure difference between the vapor deposition chamber 9 and the atmosphere.

Next, the vapor-deposited tapered steel strip is transferred to the deflector roll 8'.
It passes through an exit sealed furnace 16 (the vacuum pressure is increased in stages), goes out into the atmosphere, and is wound onto a two-winding reel 17.

In addition, in the above-mentioned apparatus, a non-oxidation furnace or an oxidation furnace filter,
Reduction furnace 4. The cooling furnace 5 may be removed and the copper strip before vapor deposition may be irradiated with an electron beam in the vapor deposition chamber 9 to activate the surface of the copper strip. With this device, zinc 1 in 18 evaporating pots
Although the heating in step 4 was performed using a heater, this may also be performed using electron beam heating.

As seen in the results of Example 1 and FIG. 2, which will be described later, the boundary between when a good plated film is obtained and when it is not corresponds to the experimental formula 义=25 ogP-+16 .

The board temperature is [25j! ngP(Tnrr)+163)
(If the temperature is less than 'c>, excellent adhesion cannot be obtained.The reason for this is thought to be as follows.If the vacuum pressure is high, vaporized zinc tends to become an oxide, and if the substrate temperature is low, zinc Since the bonding effect of the steel plates is reduced, it can be said that excellent adhesion can be achieved within an appropriate range of conditions.

As mentioned above, the plating layer becomes thinner due to re-evaporation of zinc.

Next, examples of the present invention will be described.

Example 1 As a plating substrate, the plate thickness was 1. Qrnm size 60
A cold-rolled steel plate of 60 mm was used. Prior to vapor deposition, the surface of the steel plate was degreased. After this steel plate was pretreated under the conditions shown in Table 1 (annealing was also performed at the same time), it was led to a vacuum deposition chamber without being exposed to the atmosphere, and zinc was deposited at TC air pressure and substrate temperature not shown in Table 1. I did it.

To evaluate the plating adhesion of the resulting damped steel sheet, we made a close contact surface bending with a bending radius of 0 so that the plated surface was on the outside, and then applied Sellotape to this part. When the Sellotape was removed, the zinc adhering to the Sellotape was Adhesion was evaluated based on the amount of The results are shown in Figure 2.

Evaluation of paint film adhesion was performed as follows. The resulting pre-painted steel plate was treated with zinc phosphate chemical conversion treatment (
After applying Granodin np50o0 (trade name), cationic electrodeposition coating was applied. This painted steel plate was immersed in boiling water for 2 hours, then lifted, and a cutter knife was used to cut 100 1-dragon square squares into the base pattern, and an overhang of 2 mm was applied using an Erichsen tester. did. Next, this treated area was covered with cellophane tape, and when it was removed, the paint film adhesion was evaluated based on the percentage (%) of the paint that adhered to the cellophane tape. The results obtained are shown in Table 1. In addition.

The symbols in the table indicate the results obtained by coating an electrogalvanized steel sheet under the same conditions as described above, examining the adhesion of the coating, and comparing it with the two according to the present invention.

As seen in Table 1, the temperature is 25i0gP (Tor
r)+165 or more! Galvanized steel sheets obtained under conditions up to +00'C (290°C) have excellent plating adhesion, and galvanized steel sheets obtained under the above conditions below 200'C have excellent plating adhesion. In addition, it has paint film adhesion, which is superior to that of electrogalvanized steel sheets.

333 Example 2 A cold-rolled steel strip with a plate thickness Q of 6 rnvr and a plate width of 5 oomm was used as a plating substrate, and vacuum evaporation plating was carried out under the conditions shown in Table 2 using the continuous evaporation plating apparatus shown in Fig. 1. went. The adhesion and coating adhesion of the obtained dampened steel plate were evaluated in the same manner as in Example 1. The results obtained are shown in Table 2. It is clear from the wood surface that the material according to the present invention has excellent mating adhesion and coating adhesion.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an example of an apparatus for carrying out the method of the present invention. FIG. 2 is a diagram showing the relationship between the plating substrate temperature, the vacuum pressure of the plating atmosphere, and the abutment adhesion in the method of the present invention. Patent applicant Nisshin Steel Co., Ltd.

Claims (1)

[Claims] 1. In a method for manufacturing galvanized steel sheets by vacuum evaporation, the surface of a steel sheet that has been cleaned by 2M is exposed to the vacuum pressure of the atmosphere.
(Torr) and the substrate temperature during vapor deposition as T[0. 25 fflngP-) A method for producing a vacuum-deposited galvanized steel sheet with excellent plating adhesion, characterized in that vacuum deposition is performed under conditions that satisfy the relationship: 163≦T-black DO. 2. The manufacturing method according to claim 1. A method characterized in that after the surface of a steel plate is reduced and purified by 7ft in a reducing atmosphere containing hydrogen, vacuum evaporation zinc plating is continuously applied. A manufacturing method according to claim 1 or 2, characterized in that it is carried out at a temperature of 200''C or less.