JPH04301099A - Electrolytic pickling and polishing method - Google Patents

Abstract

PURPOSE:To stabilize polishability and to improve efficiency by mixing and forming the electrolytic bath to be used for electrolytic polishing just before a stage in a polishing device, thereby forming and supplying the electrolytic bath optimum for a material to be polished at proper times. CONSTITUTION:An electrolyte stock tank 31 and a paste forming agent stock tank 32 are held respectively independently. The information on polishing by external input or automatic detection is inputted from an input terminal 37 to an electrolytic bath controller 29. An electrolyte replenishing pump 34, a paste forming agent replenishing pump and a washing water supplying pump 26 are driven and stopped at proper times according to the signal based thereon and the electrolytic bath is injected into an electrolytic bath mixing tank 30 and is mixed therein. The always optimum electrolytic bath 24 is, therefore, supplied to soft pads 11 of respective polishing electrodes 10 by a pump 4, by which the material to be polished is electrolytically pickled and polished.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic pickling and polishing method, and more particularly to a partially electrolytic pickling and polishing method using a moving electrode system using a paste electrolytic bath.

0002

[Prior Art] Mill scale removal methods for thick steel plates include so-called mechanical removal methods, such as shot blasting/sandblasting, grindstone/belt grindstone, etc., or a combination of both, and acid removal methods such as those for stainless steel. A chemical removal method using a washing tank has traditionally been used.

In response to this, a partial electrolytic pickling polishing method using a moving electrode method, which is an electrochemical polishing method, has been developed (see, for example, Japanese Patent Laid-Open No. 4500/1983).

The polishing method, which is an electrochemical method, can reduce the polishing load compared to the mechanical polishing method, generate less heat during polishing, and suppress the occurrence of polishing distortion. Furthermore, since it is a partial pickling and polishing method using a moving electrode, the equipment can be made smaller and more efficient than the pickling method using a pickling tank, and it is also possible to treat only one side.

Partial electrolytic pickling and polishing method using a moving electrode method (
Electrolytic polishing (hereinafter abbreviated as electrolytic polishing) is used for thick steel plates that cannot be continuously passed through a pickling tank, such as thin steel plates, and for electrodes (rotation, revolution, a combination of both, or vibration). For some reasons, such as partially processing while moving the electrode, a paste-like electrolytic bath and a soft pad (with mechanical polishing ability) to hold this electrolytic bath between the electrode and the material to be polished are used. A small amount of abrasive grains may be mixed in to apply the abrasive grains) is attached directly below the electrode.

[0006] The characteristics required of the electrolytic bath used in the electrolytic polishing are sufficient electrical conductivity (
It can be said that the content of electrolyte), the appropriate viscosity (degree of pasting), and the appropriate acidity to impart chemical polishing ability.

[0007]

[Problem to be solved by the invention] An electrolytic bath that satisfies these characteristics is prepared in advance at an electrolytic bath manufacturing facility, and
It will be used for electrolytic polishing. Among the required characteristic values, acidity is determined based on the acid resistance of the equipment and the constraints of the working environment.
Material of the material to be polished, scale layer composition and scale layer thickness (
The appropriate value differs depending on the characteristics of the material to be polished (hereinafter referred to as the characteristics of the material to be polished). Furthermore, the amount of electrolyte needs to be adjusted because the amount of electricity required varies depending on the characteristics of the material to be polished. Furthermore, as mentioned above, viscosity is an important characteristic for maintaining the electrolytic bath well under the electrode because of the moving electrode method used for partial polishing. Polishing conditions (electrode rotation speed, distance between electrodes (electrode to polished material), soft pad material, etc.)
In addition, the appropriate value differs depending on the environmental conditions (air temperature, temperature of the material to be polished). Therefore, the characteristics of the material being polished, the environmental conditions,
If the polishing conditions are different, the polishing performance of one type of electrolytic bath will not be stable.On the other hand, in order to stabilize the polishing performance, electrolytic baths corresponding to the number of combinations of each condition are required. This makes it difficult to process a wide variety of materials to be polished.

Furthermore, as mentioned above, in electrolytic polishing, the heat generated during polishing is smaller than that in mechanical polishing, but cannot be completely ignored, and furthermore, because a paste-like electrolytic bath with relatively low thermal conductivity is used. , in an electrolytic bath (between the electrode and the material to be polished)
As the polishing progresses, the viscosity changes as the temperature of the electrolytic bath changes. Such changes in viscosity during polishing operations could not be effectively dealt with by the method of supplying an electrolytic bath prepared in advance.

Furthermore, conventionally, when a plurality of types of electrolytic baths are used, it is necessary to install stock tanks in the polishing apparatus in the same number as the types of electrolytic baths, which increases the size of the apparatus. To prevent this increase in size, a small number of stock tanks (
In extreme cases, if one tank is used, each time the electrolytic bath is switched, it is necessary to remove the used electrolytic bath from the tank, clean the tank, and pour a new electrolytic bath into the tank, which takes a lot of time and reduces the equipment. The operating rate was decreasing. Furthermore, if it is difficult to recover the remaining electrolytic bath in the tank at the time of switching, the remaining electrolytic bath must be discarded, and an increase in the basic unit of electrolytic bath is unavoidable.

FIG. 5 is a flowchart showing an example of a conventional partial electrolytic polishing method in the case of one stock tank.

In FIG. 5, numeral 2 is an electrolytic bath stock tank in which the pasty electrolytic bath 1 is charged, numeral 14 is a preheating heater, and numeral 15 is a stirrer. Further, a pump 4 and a relief valve 5 are provided at the lower part of the tank 2, and the electrolytic bath can be circulated through a pipe 6.

When replacing the electrolytic bath 1, the electrolytic bath discharge valve 8 is opened and the electrolytic bath is discharged from the discharge pipe 7 via the electrolytic bath supply pipe 3.

During polishing, one or more polishing electrodes 10 are provided facing the polishing surface of the material 12 to be polished, each with a soft pad 11 in contact with the polishing surface. 16
17 is a current-carrying brush, 17 is a current-carrying electrode for the material to be polished, 18 is a cable, and 19 is an electrolytic power source.

The pasty electrolytic bath is supplied to the polishing electrode 10 through the electrolytic bath supply pipe 3 and through the electrolytic bath supply header 9 while adjusting the flow rate with a flow meter 13 and a pump 4.

[0015] In order to perform the polishing work smoothly with such a conventional device, the capacity of the stock tank 2 must be 200 ml.
Requires ~300 liters.

The present invention solves the above-mentioned problems and adapts to changes in the characteristics of the material to be polished, environmental conditions, and polishing conditions in a partial electrolytic pickling polishing method using a moving electrode method using a paste electrolytic bath. The object of the present invention is to provide an electrolytic pickling polishing method with stable polishing performance.

[0017]

[Means for Solving the Problems] According to the present invention, in order to achieve the above object, partial electrolytic pickling is carried out by applying current between a material to be polished and a moving electrode using a paste electrolytic bath. , at least one electrolyte and at least one pasting agent, using an electrolytic bath in which the type and composition ratio of the electrolyte and the pasting agent are controlled according to the characteristics of the material to be polished and environmental conditions. An electrolytic pickling and polishing method is provided, which is characterized in that electrolytic pickling and polishing is carried out under the following electrolytic conditions.

The present invention will be explained in more detail below with reference to FIG.

FIG. 1 is a flowchart of an electrolytic pickling and polishing method showing an embodiment of the present invention. In the present invention, an electrolyte stock tank 31 and a pasting agent stock tank 32 are independently provided, and the characteristics of the material to be polished and the polishing conditions (by external input or automatic detection) input through the input terminal 37, the temperature meter of the polishing part, and the viscosity. total 27 and the generated voltage (by voltmeter 28), as well as the paste electrolyte bath 2 after mixing.
The information on the values 25 of the thermometer, pH meter, liquid level meter, and viscometer in step 4 is input to the electrolytic bath control device 29, and based on this, the electrolytic bath control device 29 controls the electrolyte replenishment pump 34, pasting agent replenishment pump, and The purified water supply pump 26 is driven and stopped at appropriate times, and each electrolyte 20, 21 and each pasting agent 22, 23 are injected and mixed into the electrolytic bath mixing tank 30, and the electrolytic bath supply pump 4 always supplies the optimum electrolytic bath 24. is supplied to the soft pad 11 of each polishing electrode 10 for electrolytic pickling polishing. Note that 36 is a check valve.

When switching the electrolytic bath, the electrolytic bath discharge valve 8 is opened and the electrolytic bath supply pump 4 is operated to discharge or recover the electrolytic bath from the system. Further, cleaning of the mixing tank 30 and subsequent parts can be easily performed by using purified water from the purified water supply pipe 33.

FIGS. 3 to 5 show Na2 as the electrolyte, respectively.
It is a graph showing the relationship between electrolytic bath temperature and viscosity, the relationship between pasting agent addition rate and viscosity, and the relationship between electrolyte mass and generated voltage when using SO4 and sodium polyacrylate as a pasting agent. From these, the target acidity, viscosity, etc. corresponding to the material to be polished, polishing conditions (speed, amount of electricity input, etc.) and the relationship between each of the above factors are registered in advance in the electrolytic bath control device, so that the electrolytic bath is always optimal. It can be seen that stable polishing is possible.

Further, according to the present invention, since the composition ratio of the electrolyte and the pasting agent is 5 to 20%, the capacity of each stock tank may be small, and the equipment can be downsized.

In addition, the capacity of the electrolytic bath mixing tank is small enough to slightly exceed the amount supplied to the polishing section in order to always supply the optimum electrolytic bath to the polishing section and to reduce loss during switching. can be converted into

[0024] In the above explanation, two types of electrolytes and two types of pasting agents are installed, but there is no restriction on the number of each, and the combination of electrolytes and pasting agents to be mixed is subject to principle. There are no restrictions. In addition, the electrode 10
The number is not limited to three.

[0025]

[Operation] According to the present invention, the characteristics of the material to be polished, the environmental conditions,
After changing the type of electrolyte (acidity), amount of electrolyte, and amount of pasting agent in the polishing equipment as needed according to the electrolytic conditions,
Can be mixed and supplied to the polishing section. Furthermore, the electrolyte temperature in the polishing part, the temperature of the material to be polished, and the generated voltage can be adjusted to prevent changes in the electrolyte retention force caused by the heat generated during polishing, the contamination of removed scale in the polishing part, and changes in the soft pad over time. You can respond by detecting it.

[0026] Therefore, it has become possible to polish various materials to be polished with stable polishing performance using an appropriate electrolytic bath without having to prepare a large number of paste electrolytes with the same apparatus.

[0027] According to the present invention, it is sufficient to carry necessary types of electrolyte and pasting agent, and usually these are contained in an amount of 5 to 20 wt%.
Since it is an additive, each loading capacity can be small, and the equipment can therefore be downsized. Furthermore, it can be made small enough to satisfy the required supply amount as a mixing tank, and electrolytic bath loss and switching time loss when switching electrolytic baths can be significantly reduced.

[0028]

EXAMPLES The present invention will be specifically explained below based on examples.

(Example 1) Na2 SO4 as electrolyte
A thick steel plate (SUS30
Mill scale was removed from 4-equivalent steel (20 mm thick).

Each electrolyte tank and pasting agent tank has a capacity of 20 liters, one electrolyte bath mixing tank has a capacity of 5 liters, and a soft pad (thickness 30 mm x 220 mm)
φ) was used.

Under the above conditions, first, the electrolysis voltage was 15V, and the electrolyte viscosity to the polished area was controlled to be 30×103 poise, and then the electrolysis voltage was 10V, and the electrolyte viscosity to the polished area was controlled to be 10×103 poise. Poise and targeted control were performed. The electrolyte loss during this time was 5 liters (of which NaS
(containing about 0.5 liters of O4 and about 0.3 liters of polyacrylic acid), the switching time loss was about 1 minute, and stable polishing was performed under all conditions.

[0032]

[Effects of the Invention] Since the present invention is constructed as described above, an electrolytic bath used for electrolytic polishing is created by mixing an electrolyte, a pasting agent, and purified water in a polishing device, and is applied to the polishing part. Because of this feeding method, the electrolytic bath most suitable for the characteristics of the material to be polished, environmental conditions, and polishing conditions can be created and supplied at any time, making it possible to stabilize the polishing performance.

Furthermore, the electrolyte and the pasting agent are stored independently, and purified water, which usually has the highest mixing ratio, can be introduced from outside, making it possible to downsize the equipment.

Furthermore, by optimizing the capacity of the mixing tank, it is possible to reduce losses when switching electrolytic baths.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing an example of the electrolytic pickling and polishing method of the present invention.

FIG. 2 is a graph showing the relationship between electrolytic bath temperature and viscosity when an electrolyte of 10% Na2SO4 and a pasting agent of 5% sodium polyacrylate are mixed.

FIG. 3 is a graph showing the relationship between the amount of pasting agent sodium polyacrylate added and viscosity at an electrolytic bath temperature of 30°C.

[Figure 4] Electrolyte Na2 SO4 at electrolytic bath temperature of 30°C
It is a graph showing the relationship between the addition amount and the electrolytic voltage.

FIG. 5 is a flow diagram showing a conventional partial electrolytic polishing method.

[Explanation of symbols]

1 Paste electrolytic bath 2 Electrolytic bath stock tank 3 Electrolytic bath supply piping 4 Electrolytic bath supply pump 5 Relief valve 6 Relief piping 7 Electrolytic bath discharge piping 8 Electrolytic bath discharge valve 9 Electrolytic bath supply header 10 Polishing electrode 11 Soft pad 12 To be polished Material 13 Flow meter 14 Electrolytic bath preheating heater 15 Electrolytic bath stirrer 16 Current-carrying brush 17 Current-carrying electrode for polished material 18 Cable 19 Electrolytic power source 20, 21 Electrolyte 22, 23 Pasting agent 24 Paste electrolytic bath after mixing 25 After mixing Electrolytic bath thermometer, pH meter, liquid level meter, viscometer 26 Clean water supply pump 27 Polishing part thermometer, viscometer 28 Voltmeter 29 Electrolytic bath control device 30 Electrolytic bath mixing tank 31 Electrolyte stock tank 32 Pasting agent stock tank 33 Clean water supply piping 34 Electrolyte replenishment pump 35 Pasting agent supply pump 36 Check valve

Claims (1)

[Claims] Claim 1: When performing partial electrolytic pickling by applying current between the workpiece to be polished and a moving electrode using a pasty electrolytic bath, the workpiece to be polished is partially electrolytically pickled from at least one electrolyte and at least one pasting agent. Electrolytic pickling is characterized by carrying out electrolytic pickling and polishing under predetermined electrolytic conditions depending on the material to be polished using an electrolytic bath in which the type and composition ratio of electrolyte and pasting agent are controlled according to the characteristics and environmental conditions. Polishing method.