JPH02279215A - Polishing method for inner surface of metallic conduit - Google Patents

Abstract

PURPOSE:To easily and satisfactorily mirror-polish the inner surface of a metallic conduit, and especially of a small-diameter pipe by making both electro polishing and mechanical polishing. CONSTITUTION:While a polishing buff 11 is travelled in the axial direction together with an electrolyte flow pipe 9 in a metallic conduit, the metallic conduit is rotated. Further, an electro polishing liquid is supplied form an electrolyte passage 8 of the flow pipe 9 through an outflow port 12 and an electrolyte passage 8 of the polishing buff 11 to the inner surface of the metallic conduit. In such a condition, the metallic conduit is used as an anode and a designated voltage is applied between the anode and a cathode, so that the inner surface of the metallic conduit is electro polished by the action of the electrolyte. With this operation, the inner surface of the metallic conduit is mechanically polished by the polishing buff 11. Thus, the inner surface of the metallic conduit is mirror-polished.

Description

[Detailed Description of the Invention] Industrial Example: Rizuki Ribun, Field - The present invention efficiently polishes the inner surface of a metal tube such as stainless steel by combining mechanical and electrochemical methods. Regarding the method.

For example, stainless steel pipes used for transporting chemical liquids in food processing and pharmaceutical manufacturing processes require a particularly smooth inner surface that comes into contact with the liquid. Requires polishing.

In this case, when the inner diameter of the pipe is large, a mechanical polishing method using a grindstone is mainly used, and polishing is performed by rotating a polishing tool inserted into the hollow part of the pipe at high speed, but when the inner diameter of the pipe is small, , especially if the inner diameter is 20m
When the diameter is less than m, it becomes structurally impossible to rotate the tool at high speed within the pipe, and therefore it becomes difficult to apply a mechanical polishing method using a grindstone or the like. Therefore, the conventional method was (1) electrolytic polishing.

Performing only chemical polishing, (2) Passing a viscoelastic abrasive material under pressure, (3) Passing abrasive grains mixed with a high-pressure flow of water, air, etc., (4) Thread with abrasive grains attached. Methods such as passing the

However, all of the above conventional methods have weak polishing power, and it is extremely difficult to smooth a rough surface and finish it into a mirror surface with a surface roughness of RmaxO,5/a or less. In particular, in methods in which only electrolytic polishing or chemical polishing is performed, the polishing power is significantly reduced depending on the material of the object to be polished, making it impossible to obtain a jm surface.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method that can efficiently mirror-finish the inner surface of a small-diameter metal tube easily and inexpensively without rotating a polishing tool.

In order to achieve the above object, the present invention has an electrolyte flow tube formed of an elastic material having liquid permeability on the outer circumferential surface of an electrolyte flow tube in which an electrolyte passage is formed along the axial direction. A polishing buff having a liquid flow path is provided, and an electrolyte outlet is formed in the peripheral wall of the electrolyte flow pipe to communicate the electrolyte flow path with the electrolyte flow path of the polishing buff. By inserting the polishing buff into the metal tube, the outer peripheral surface of the polishing buff is brought into contact with the inner surface of the metal tube, and the electrolyte distribution tube is isolated from the inner surface of the metal tube for a predetermined period through the electrolyte flow path of the polishing buff. A cathode is provided so as to face each other, and the polishing buff is rotated while running along the axial direction inside the metal tube together with the electrolyte distribution tube, and a cathode is provided so as to face the electrolyte distribution tube. By supplying an electrolytic polishing liquid to the inner surface of the metal tube through the electrolyte outlet and the electrolyte flow path of the polishing buff, and by using the metal tube as an anode and passing electricity between it and the cathode, the polishing buff polishes the inside of the metal tube. Provided is a method for polishing the inner surface of a metal tube, characterized in that the surface is mechanically polished and the inner surface of the metal tube is electrolytically polished using the electrolytic solution.

Here, the metal tube to be polished in the method of the present invention may be any metal tube to which ordinary electrolytic polishing can be applied, and examples thereof include those made of steel, stainless steel, titanium, nickel, aluminum, chromium, etc. In this case, the diameter of the metal tube is not limited, and according to the device of the present invention, the inner diameter is 2
Even the inner surface of a small diameter pipe of 0 am or less, for example about 5 Ilfl, can be efficiently mirror-polished.

In addition, as the polishing buff used in the present invention, nonwoven fabric, woven fabric 1
A material made of a flexible material having an internal communication space, such as synthetic resin or sponge, can be preferably used. Incidentally, abrasive grains can be fixed to the polishing buff as necessary.

Further, the rotation speed of the metal tube is 100 to 2000 rpm, especially 1000 to 1500 rpm, and the running speed of the polishing buff is 0.
．． It is preferable to set the rotation speed to 0.05 to 5 m/min, particularly 0.2 to 1 m/min, so that the inner surface of the metal tube can be mirror-polished efficiently by both mechanical polishing and electrolytic polishing. and buff running speed are influenced by the roughness of the material and are not limited thereto.

Note that the cathode can be formed of an electrolyte flow tube, but is not limited thereto.

The electrolytic solution used in the present invention is composed of an electrolyte and a solvent that dissolves the electrolyte. In this case, the electrolyte may be one that is commonly used for electrolytic polishing, and is selected depending on the material of the object to be polished. Examples include sodium nitrate, aluminum nitrate, and common salt. Water is used.

The concentration of this electrolyte can also be made similar to that of a normal electrolytic polishing solution. Note that the electrolytic solution can contain abrasive grains as necessary, and in this case, it is preferable to add abrasive grains and a surfactant for dispersing the abrasive grains to the electrolytic solution to form a slurry.

In the present invention, when fixing abrasive grains to a polishing buff or adding abrasive grains to an electrolytic solution, the type of abrasive grains may be a powder type commonly used as an abrasive material. White alundum, zirconia, carborundum, alundum, silicon carbide, alumina, alumina hydrate, chromium oxide, iron oxide, iron oxide, titanium oxide, cerium oxide A
x, ordinary abrasive materials such as calcium carbonate, abrasive materials, polishing materials, etc., and one or more of these can be used, but white arundum and alumina are particularly preferred. Although the particle size of the abrasive grains is not particularly limited, it is preferably 1O2 or larger.

In addition, when adding abrasive grains to the electrolyte, the content of abrasive grains in the electrolyte should be 2 to 20% by weight of the total, especially 5 to 1-0% by weight.
It is preferable that In this case, it is preferable that the abrasive grains be negatively charged in the electrolyte.
It is effective to pre-treat abrasive grains that are not negatively charged to a negative tF charge in an electrolytic solution, such as by treating them with an r-metal silane coupling agent. That is, when the abrasive grains have a negative bias of 4 pF, they are attracted to the positively charged object to be polished, and their electrophoretic action provides better and more reliable abrasive polishing action. In addition,
The type of surfactant for dispersing the abrasive grains in the electrolytic solution may be any surfactant as long as it can disperse the abrasive grains without being affected by the electrolyte, such as sodium alkylbenzene sulfonate. Its content can be 0.1 to 5% by weight of the electrolyte.

Function - In the present invention, by applying a predetermined voltage between the metal tube (anode) and the cathode, the inner surface of the metal tube is electrolytically polished by the action of the electrolytic solution, and the polishing buff is applied to the metal. The inner surface of the metal tube is mechanically polished by the polishing buff by running it in contact with the inner surface of the tube and rotating the metal X-tube. Therefore, according to the present invention, the inner surface of a metal tube can be polished efficiently and with excellent surface gloss and smoothness by both electrolytic polishing and mechanical polishing, which is why conventional mechanical polishing has been difficult to apply. The inner surface of a metal tube with a small inner diameter can be polished using conventional methods such as electrolytic polishing, chemical polishing alone, passing a viscoelastic abrasive under pressure, or mixing abrasive grains with a high-pressure stream of water, air, etc. Compared to methods such as threading or threading with abrasive grains, mirror polishing can be achieved better. In this case, in the present invention, the metal tube is not rotated, and the polishing tool is simply moved inside the metal tube without rotating, so it is structurally reasonable, and therefore the polishing tool can be inserted into the tube. The inner surface of a small diameter metal tube 1f can be polished simply and inexpensively by both mechanical polishing and electrolytic polishing.

EXAMPLES Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the examples described in F.

11A shows an example of a polishing device used in an embodiment of the present invention.

In the figure, reference numeral 1 indicates a metal tube as the object to be polished, and this metal tube 1 has gap rollers 3, 3.3 and press rollers 4, 4, and 1 whose outer peripheral surfaces are respectively connected to a rotating shaft 2.2. It is rotatably supported by the rollers 3, 3.3, and rotated by the rotation of the rollers 3, 3.3. In addition, 5 in Figure 1 indicates the clearance motor of the sliding roller 3, 3.3.
Reference numeral 6 denotes an electrode row that passes through the metal tube 1 to positively charge the metal tube 1.

Further, 7 in Fig. 5 indicates a sharpening tool 4g whose tip is inserted into the metal tube 1. As shown in FIG. 2, this polishing tool 7 has an electrolyte Mlε passage tube 9 in which an electrolyte passage 8 is formed along the axial direction and whose tip is closed. is formed of an elastic material with liquid permeability such as sponge or non-woven fabric on the outer circumferential surface, and an electrolyte flow path (
A cylindrical polishing buff 1]- having an internal communication space 10 is disposed and fixed, and the electrolyte flow path 8 and the electrolyte flow of the polishing buff 1 are provided on the peripheral wall of the distribution pipe 9. A plurality of circular electrolyte outflow holes 12 communicating with the passage 10 are formed along the radial direction. In addition, in the figure, 1-3-1 is a rubber coating that covers the peripheral surface of the distribution pipe other than the location where the polishing buff is installed, a brazing coating made of synthetic resin, etc. It is a cathode body that is fixed and charges the flow tube to 9 minus.

Further, the proximal opening of the J-distribution pipe 9 is closed with a stopper 15, and the tip of a flexible hose 16 that can be expanded and contracted is
- It is inserted into the 11ε passage pipe (, ) through the plug body 15, and the base end of the flexible hose 1 (3) is connected to one end of the electric M liquid supply pipe 18 via the liquid feed pump 1-7. Further, the other end of this supply pipe 18 is connected to the electrolyte tank 1.
It is inserted into the electrolytic polishing liquid 20 injected into the
By operating the pump 17, the electrolytic solution 2o is sequentially passed through the supply pipe 18 and the flexible hose 16 and is supplied to the passage 8 of the distribution pipe 9, and this electrolytic solution is transferred to the outlet 12 and the electrolytic solution flow path of the polishing buffet 1. 10 and is supplied to the inner surface of the metal tube 1.

Furthermore, one end of a wire 21 is fixed to the tip of the flow pipe 9, and the other end of this wire 21 is attached to a winding roller 22, and as shown in FIG. By inserting the flow pipe 9 into the wire 21 and rotating the 1 take-up reroller 22, the flow pipe 9 is inserted into the wire 21.
It is pulled by the polishing buff 11 and runs along the axial direction inside the flow pipe 1.

In addition, in the figure, 23 is a drain tank disposed below the metal tube 1, 24 is a reflux pipe provided between the drain tank 23 and the electrolyte tank 19, and 25 is a drain pipe installed in the reflux pipe 24. The filter 26 is a liquid pump, and the electrolytic solution supplied from the flow pipe 9 to the metal tube 1 falls into the drain tank 23, is stored in the tank 23, and operates the liquid pump 26. By doing so, the electrolytic solution 20 in the tank 23 is returned to the electrolytic solution tank 19 through the reflux pipe 24 and the filter 25.

When polishing the inner surface of the metal tube 1 using the above device, first, the polishing buff 11 of the tool 7 is press-fitted into the metal tube 1 from the opening at one end of the metal tube 1. Make pressure contact with the inner surface. Note that at this time, the buff 11 is held at one end inside the buff 1 with metal. On the other hand, by applying electricity from the electrode roller 6 to make the metal tube 1 an anode and the electrolyte flow tube 9 a cathode, electricity is passed between the two electrodes.

The flow tube (cathode) 9 is placed in a state where it faces the inner surface of the metal tube (anode) 1 via the electrolyte flow path 10 of the buff 11 with a predetermined distance between the flow tube (cathode) 9 and the electrolyte flow path 8 by the operation of the pump 17. The electrolyte is supplied from the outlet 12 to the inner surface of the metal tube 1 through the electrolyte channel 10. Then, by operating the motor 5 to rotate the metal tube 1 and rotating the winding roller 22 to run the buff 11 from one end of the metal tube 1 to the other, the entire inner surface of the metal tube 1 is polished by the polishing buff. It is mechanically polished and electrolytically polished using an electrolytic solution.

Therefore, according to the above-mentioned apparatus, by using both mechanical polishing and electrolytic polishing, it is possible to satisfactorily mirror-polish the inner surface of the metal tube. In this case, since the metal tube 1 is rotated in the above device, the tool 7 only needs to be inserted into the metal tube 1 and run along the axial direction. As such, there is no structural unreasonableness,
Therefore, it is possible to simply polish the inner surface of a small diameter tube using a tool, which has been difficult in the past.

Hereinafter, the effects of the present invention will be specifically illustrated by experimental examples.

If you use the device shown in Figures 1 and 2, use the device shown in Figures 1 and 2 to make a
The inner surface of a pipe made of stainless steel (SUS304) (inner surface roughness Rmaxl, 3 units) was polished. In this case, the polishing tool and polishing conditions were as follows. The results are shown in Table 1.

Polishing tool electrolyte distribution pipe; diameter 1 + at the tip of a copper pipe with an outer diameter of 6 m and an inner diameter of 3 IIn.
12 electrolyte outflow ports of a are formed. The outer periphery was coated with vinyl.

Polishing buff: A cylindrical item with an outer diameter of 20 inches and a width of 50 mm, made of non-woven fabric to which white alundum (#800VA) is fixed.

Electrolyte Sodium nitrate 20 g / Q Sodium nitrite l Og / Q Electrolyte supply amount 100 nA / minute Electrolysis conditions 0, 2 A / d rd Metal tube rotation speed 800 rpm Polishing tool running speed 0.1 m / min, 0.5 m /min.

1m/min No. table Cylindrical.

Electrolyte Sodium nitrate 15 g/Q Sodium nitrate], Og/Q Experiment Example No. Using the '3A position shown in Figure 1.2, inner diameter 5mm, length]
The inner surface (inner surface roughness Rmaxo: 84) of a pipe made of -In stainless steel (SUS304) was polished. In this case, the polishing tools and polishing conditions were as described in 1. The results are shown in Table 2.

Polishing tool electrolyte flow pipe: A copper pipe with an outer diameter of 2°5m and an inner diameter of 11fi, with 10 electrolyte outlet ports each having a diameter of 1m formed at the tip. In addition, the outer periphery was Biehlko 1-shi.

Polishing buff: Made of sponge with outer diameter of 10 IN and width of 50 N. Electrolyte supply amount: 30 d/min. Electrolysis conditions: 0, : 3 A, / d. Metal tube rotation speed 600 rpm, 800 rl]nl
+]-500rpra Polishing tool traveling speed 0. ], m/min Table 2 From the results in Tables 1 and 2, it is recognized that according to the present invention, it is possible to mirror-polish the inner surface of a small-diameter pipe with an inner diameter of 15 m or 5 m.

As explained above, according to the present invention, the inner surface of metal pipes, especially small diameter pipes, can be polished using simple and inexpensive equipment by both fusing and electrolytic polishing. It is a mirror that can be polished.

[Brief explanation of drawings]

FIG. 1 shows an example of a polishing apparatus 71 used in carrying out the present invention.
One part is a schematic sectional view, and FIG. 2 is an enlarged sectional view showing a polishing tool of the same apparatus. ]8・Gold JJn tube 7・Abrasive tool 8・Electrolyte passage 9...Electrolyte distribution pipe 10・Electrolyte flow g 1
1. Tokufuma buff 12. Electrolyte outflow outlet 1. fl'f people

Claims (1)

[Claims] 1. A polishing buff made of an elastic material having liquid permeability and having an electrolyte flow path inside is disposed on the outer peripheral surface of an electrolyte flow pipe in which an electrolyte flow path is formed along the axial direction, Further, an electrolyte outlet is formed in the peripheral wall of the electrolyte flow tube to communicate the electrolyte passage with the electrolyte flow path of the polishing buff, and by inserting the polishing buff into the metal tube, the outer periphery of the polishing buff is The surface and the inner surface of the metal tube are brought into contact with each other, and a cathode is provided in the electrolyte flow tube so as to face the inner surface of the metal tube with a predetermined distance from the inner surface of the metal tube through the electrolyte flow path of the polishing buff. The polishing buff is moved along the axial direction inside the metal tube together with the electrolyte distribution tube while the metal tube is rotated, and the electrolyte outlet of the electrolyte distribution tube is connected to the electrolyte flow path of the polishing buff. By supplying an electrolytic polishing liquid to the inner surface of the metal tube through the metal tube and using the metal tube as an anode and passing electricity between it and the cathode, the polishing buff mechanically polishes the inner surface of the metal tube, and the electrolyte polishes the metal. A method for polishing the inner surface of a metal tube, characterized in that the inner surface of the tube is electrolytically polished.