JPS6086294A - Preparation of sn-plated steel plate having extremely thin plating layer reduced in pinhole defect - Google Patents

Abstract

PURPOSE:To obtain the titled plated steel plate excellent in corrosion resistance, by appling pulse electrolytic Sn-plating to a steel plate, to which Ni-plating is applied in a predetermined thickness, through felt impregnated with a Sn-plating solution. CONSTITUTION:The outer periphery of an anode conductor roll 1 is surrounded by current passing felt 2 impregnated with a plating solution and the lower part thereof is immersed in the Sn-plating solution 4 in a storage container 3. A steel plate 5, to which Ni-plating is applied in a thickness of 0.002-0.5mum, is run so as to be contacted with the outer periphery of the roll and pressed to the outer peripheral surface of the roll 1 by a cathode conductor roll 6. The roll 6 in provided at a position corresponding to the roll contact length required by the plate 5. This plate 5 is brought to negative potential against the positive potential of the roll 1 while the plate 5 is passed between the rolls 1, 6 and a pulse electrolytic current with a duty cycle of 2-10% and a current passing time of 15- 25ms is passed through the contact length of the felt 2 with the plate 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing an ultra-thin Sn-plated steel sheet with few pinhole defects.

(Prior art) In recent years, Nsn has been used as a material for various food cans.
Due to the soaring price of Sn metal, Sn-plated steel sheets with a light weight are becoming the main type of plated steel sheet. Of course,
Conventional thin-metal Sn-plated steel sheets are manufactured using the ferrostan method or the Rodan method, in which Sn is continuously electrolytically plated with electricity.
Nople) no? Due to the E position, conventional methods have a large number of pinholes and cannot obtain a uniformly electrodeposited plating layer, resulting in a problem in single-surface corrosion.

As a solution to this problem, a plating method using pulsed current has recently been developed. The pulsed current plating method can produce Sn-plated steel sheets with excellent corrosion resistance because it produces a uniform Sn-plated layer with few pinholes using flat scraps, but it generally has low electrolytic deposition efficiency and is inferior to conventional ferrostanned In pulse electrolytic Sn plating using the halogen method or the halogen method, the distance between the electrode and the steel plate that is the unplated material (distance between electrodes) is wide, resulting in a large amount of power loss during plating.

Generally, the amount of Sn mesh on one side is 0.05 to 0.597 m.
In the case of ultra-thin steel sheets such as No. 2, conventional manufacturing methods had many pinholes in the Sn coating layer, which caused problems in corrosion resistance during use.

(Object of the invention) The present invention provides a method in which the amount of Sn coating on one side as described above is 05jl/
Solved various problems with ultra-thin Sn-plated steel sheets with a basis weight of m2 or less. In particular, it provides a manufacturing method that reduces the occurrence of pinhole defects.

(Structure of the Invention) The gist of the present invention is to apply N1 plating to a thickness of 0.002 to 0.05μ on a steel plate, and then to form a cathode conductor that is suppressed in an anode conductor surrounding a felt impregnated with Sn plating solution and a roll. While passing between the rolls, the duty cycle is 2 to 10% and the energization time is 15 to 2.
This is a method for producing an ultra-thin Sn-coated steel sheet with few pinhole defects caused by passing a pulsed electrolytic current of 5 m5.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment used to explain the present invention, in which an anode conductor roll surrounds an electrically conductive felt 2 whose outer periphery is impregnated with a plating solution, and a portion below it is an anode conductor roll. It is immersed in plating solution 4. Sn plating solution 4
Materials suitable for pulse electrolytic plating, such as ferrostane, norogen, and alkali, are used. 5 is a running steel plate to be plated, which should be Sn plated with a thickness of 1111K and a thickness of 0.002.
The anode conductor was coated with ~0.5μ Ni.
It runs in contact with the outer periphery of the roll 1. The N tome coating layer is electrolytically coated with Ni using a commonly used bath such as a Watt bath or a sulfamine bath. Reference numeral 6 denotes a cathode conductor roll, which presses the broken plated steel plate 5 against the outer peripheral surface of the anode conductor roll J and is provided at a position corresponding to the necessary roll contact length of the steel plate 5. That is, while passing the steel plate 5 to be plated between the rolls 1.6, anode conduction is carried out! - The steel plate 5 to be plated is brought to a negative potential with respect to the positive potential of the roll 1, and while a pulse electrolytic current is generated through the felt 2, the surface of the steel plate 5 is electrolytically deposited to perform Sn plating.

However, in manufacturing the ultra-thin Sn-plated steel sheet as described above, the duty cycle is 2 during the length of the traveling steel sheet 5 to be plated that comes into contact with the felt 2 impregnated with the Sn plating solution 4.
Apply a current of ~10%.

This duty cycle indicates the ratio of the energization time during one cycle of energization and de-energization when a constant pulse electrolytic current is applied discontinuously in a constant cycle.The value is calculated using the following formula. The more important the value is, the larger the number, the -
The ratio of energization time during the cycle is the dog.

Here t. What is N? - Continuous energization time during a cycle, toF
F is the non-current time during the -cycle.

That is, in the present invention, the duty cycle is
As shown in the figure, it is determined based on the occurrence of pinholes, and if it is less than 2%, the effective current application time will be short and the time to secure the plating amount will be long, causing problems, and if it exceeds 10%, This results in a plating layer with many pinholes, resulting in poor results. Further, as for the energization time in this case, as shown in FIG. 3, the continuous energization time t during the -cycle. N is 15
If it is less than ms, the occurrence of pinholes will be large,
Moreover, if it is longer than 2.5 ms, it is inconvenient that it becomes impossible to respond flexibly to the production of ultra-thin Sn-plated steel sheets due to the relationship with the duty cycle.

In addition, in Fig. 2, j□N20 m S , toN
-total 4 seconds + i 150A/dm2, duty cycle 2% in Figure 3, toN-tOta
The conditions were 14 seconds + 1150 A/dm'' + total continuous current amount of 12 coulombs/dm2.

In addition, the Ni plating layer of the steel plate to be plated significantly reduces the number of pinholes that occur in the Sn plating layer as shown in Fig. 4 under the above duty cycles and energization times. The Ni coating layer of the present invention was determined from the pinhole reduction effect, and if it is less than 0.002μ, there is no significant difference when Sn plating is applied to a steel base, and
If μ is exceeded, the effect reaches saturation and is disadvantageous from an economic point of view.

The Sn-plated steel sheet manufactured under the conditions of the present invention as described above can be manufactured to have very few pinholes, excellent corrosion resistance, and a very thin Sn-plated steel sheet.

(Example) Next, examples of the present invention will be described.

Table 1 shows that the product was a Sn-plated steel plate with a size of 0.4 m2 on one side, and the steel plate was plated with nickel in a Watts bath, and then used for the Huetistan method and Snn plating method.
Examples of steel plates running at 2'00 m/''n are Sn-plated under various pulse electrolysis conditions, and the number of pinholes generated in the resulting products is shown in comparison with comparative materials.

As is clear from the above examples, the present invention was able to obtain a steel plate with significantly fewer pinholes and superior corrosion resistance than a comparative steel plate that deviated from the conditions of the present invention.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of equipment for implementing the method of the present invention, Fig. 2 is a graph showing the relationship between the beauty cycle and the number of pinholes, and Fig. 3 shows the relationship between the energization time and the number of pinholes. The graph shown in FIG. 4 is a graph showing the relationship between Niff1 and the number of pinholes. 1. Anode conductor roll, 2. Current-carrying tl fue/L, ), 3. Storage container, 4. Plating solution, 5°
°・Steel plate to be plated, 6...Cathode conductor roll, agent Patent attorney Tomoyuki Yabuki, 1 person, Figure 1, Figure 2, figure 3, 1 □21ri, Dennichiki r1 (n 5), brush 4 Figure 1. □

Claims (1)

[Claims] A steel plate is plated with N1 to a thickness of 0002 to 05μ, and then an anode conductor roll surrounding a felt impregnated with a Sn plating solution and a cathode conductor pressed against the roll.
Duty cycle 2 while passing between the rolls
10% and a pulsed electrolytic current of 15 to 25 m5 for a duration of t n:'j to perform Sn plating.