JPH11254289A - Device and method for polishing outer surface of metallic pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a polishing failure caused by the failed straightness, failed circularity, polishing thermal distortion, bending or the like of a metallic pipe by providing a means for adjusting the pressing force of a polishing tool in the direction of both horizontal side faces of the metallic pipe, and a means for rotating the metallic pipe by a specified angle in a divided manner with a pipe axis set as a rotary axis. SOLUTION: For polishing a traveling steel pipe, both polishing tools 4 and 4 are rotated, and a truck 2 on a rail 9 is traveled in the pipe axial direction of the steel pipe at a constant speed. For adjusting a polishing amount, the rotary motor load currents of flap wheels 4 and 4 are detected by a meter relay, and a load adjusting motor is controlled. The steel pipe is rotated in a divided manner by a metallic pipe rotating motor 7 at constant angles. After the completion of one-way traveling polishing by both polishing tools 4 and 4, the steel pipe is rotated by an amount equivalent to the polishing width of one time. Reciprocating traveling polishing is repeated, a rotational angle and a rotational speed are set in a controller by the metallic pipe rotating motor 7 so as to polish the full peripheral surface of the steel pipe, and polishing is performed fully automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-precision polishing apparatus for an outer surface of a long metal pipe, particularly a steel pipe such as a seamless stainless steel pipe or a welded stainless steel pipe, and a polishing method using the apparatus.

[0002]

2. Description of the Related Art Conventionally, as a pretreatment for forming a corrosion-resistant coating on the outer surface of a long metal tube, polishing for removing foreign substances such as surface scales and fragments and surface flaws has been carried out. A rotary polishing method using a brush or a polishing belt is used. In addition, a hairline processing method using a polishing belt and a polishing oil is also used for decorative finish polishing of a flat surface such as a stainless steel plate. As a polishing brush using a polishing brush in a rough polishing of a stainless steel tube, a rod-shaped body composed of a resin-based material, polishing abrasive grains and reinforcing fibers is mounted on a circumference of a roll surface in a standing manner (Japanese Patent Laid-Open No. 8-192366). Japanese Patent Application Laid-Open No. 7-132454), and a method using a brush material mixed with abrasive grains (Japanese Patent Application Laid-Open No. 7-132454) is known for mirror polishing of a stainless steel deformed tube. The above-mentioned Japanese Patent Application Laid-Open No. 8-192366 discloses that, as a problem of the prior art, in the polishing with a flap wheel, the base material of the wheel has a strong action of hitting the surface to be polished, and the front end of the base material is torn off and consumed. It is also pointed out that, since it is paper or cloth, the repulsive force is small and a high pressing force cannot be set, so that the grinding force is inferior.

Generally, for polishing a long metal tube, a plurality of sandpapers or buffs arranged in series by moving the metal tube forward in the tube axis direction while rotating the tube with a skewed conveying roll and a guide roll. The outer peripheral surface is polished while the peripheral surface of the polishing wheel is pressed against the metal tube. in this case,
If the straightness and roundness of the metal tube are excellent, the grinding wheel can grind the outer periphery of the metal tube under the same conditions, but in reality, the bending or irregularity of the metal tube due to the manufacturing process. The occurrence of a diameter part is inevitable. Further, in the manufacturing process, a stress due to forming or welding remains in the circumferential direction or the longitudinal direction of the metal tube, and this residual stress is released due to a decrease in wall thickness or heat input in the polishing process, resulting in a bending in a longitudinal direction or a perfect circular shape. A phenomenon that the degree is impaired also occurs. Such a phenomenon becomes a serious obstacle particularly in the case of a thin-walled tube.

To cope with this problem, the metal pipe is cold-straightened by a straightening roll before polishing, the clamping force between the grinding wheel and the feed roll is corrected, or a copying mechanism is incorporated to change the shape of the metal pipe. A method of following a wheel or the like is known. For example, the invention disclosed in Japanese Patent Application Laid-Open No. 5-208351 is an apparatus that corrects a metal tube so as to be rotatably held by a polishing wheel and a holding mechanism in accordance with a change in the shape of the metal tube.
Anti-vibration tape is attached to the inner surface of the metal tube to prevent vibration and noise. Also, the invention of Japanese Patent Application Laid-Open No. 6-321361 discloses a method in which a shape correcting device is inserted into a metal pipe in advance to correct the roundness defect and the longitudinal bending of the metal pipe, and then the metal is corrected in a state where the shape correcting device is inserted. A method for polishing the outer surface of a tube is disclosed.

[0005]

If the steel pipe is used for a pipeline, a pipe used in a general chemical plant, or a structural material of a building, a very precise outer surface polishing is not required. However, when the added value of the final product is to be increased in consideration of decorativeness, high-precision finish polishing is performed. In particular, stainless steel pipes used as piping materials for ultra-clean rooms such as semiconductor manufacturing equipment are required to have a highly clean inner surface and excellent corrosion resistance, and the outer surface is also highly polished and polished. It is necessary to completely remove foreign matter such as particles, precision-cleaning and thoroughly remove impurities and dust, inspect in a clean room, and completely package and ship.

The above-mentioned steel pipe for a plant or the like is generally manufactured to a length of at most about 4 m in consideration of transportation conditions. However, it is generated due to uneven diameter of the formed steel pipe itself and polishing heat. Deformation of the steel pipe due to distortion, warping, etc. is unavoidable, and it is difficult to finish-polish the entire peripheral surface of a long curved surface mechanically at high speed with high cleanliness like a mirror surface without causing poor polishing. In the past, conventional methods had to rely on manual work, and the polishing efficiency was poor.

[0007] Seamless steel pipes having an outer diameter of 6A to 100A (10.5 to 114.3 mm) have been used as piping materials for semiconductor manufacturing equipment and the like. 65A to 300A (76.3)
In particular, in the case of a large-diameter welded stainless steel pipe having a diameter of about 318.5 mm), there is a problem of uneven diameter, a large area is required for polishing, and the necessity for high-speed polishing is great. Therefore, the present invention
Without using a complicated straightening device as in the prior art, it is possible to reduce the poor straightness (bending), the bad roundness (uneven diameter) of the formed metal tube itself, the deformation caused by polishing heat, and the poor polishing due to warpage. An object of the present invention is to provide a polishing apparatus and a polishing method capable of mechanically finishing the outer surface of a long metal tube at a high speed while preventing occurrence of the polishing.

[0008]

According to the present invention, as a means for solving the above-mentioned problems, in an apparatus for polishing the outer surface of a long metal tube, a lower portion of the metal tube positioned in a horizontal state is parallel to the tube axis of the metal tube. A traveling rail provided on a traveling rail, a carriage reciprocating on the traveling rail, a pair of polishing tools mounted on the carriage and located on both horizontal side surfaces of the metal tube with the metal tube interposed therebetween, and a pair of polishing tools in a direction of both horizontal side surfaces of the metal tube. Means for adjusting the pressing force of the polishing tool, means for gripping both ends of the metal tube, and means for rotating the metal tube separately at a predetermined angle about the tube axis as a rotation axis. provide. In this apparatus, it is desirable to provide a receiving roll for supporting the lower surface of the long metal tube on the carriage. The polishing tool is preferably a flap wheel mounted with the rotation axis in the vertical direction.

Further, the present invention is to prevent the deformation of the metal tube due to the polishing heat by filling the inner surface of the metal tube with a cooling liquid when the outer surface of the long metal tube is polished by using the above polishing apparatus. A method for polishing an outer surface of a metal tube is provided. For this reason, as a means for gripping both ends of the metal pipe, a means having a member inserted into the end of the metal pipe and sealed with water is used.
Using the above device, the two horizontal side surfaces of the metal tube are polished while rotating the polishing tool arranged opposite to both side surfaces of the metal tube, and the metal tube is rotated by an angle of one polishing width for each run. Then, the outer surface of the metal tube can be polished by repeating the polishing of the next run. Also, by loading and polishing dummy materials having the same outer diameter as the metal tube at both ends of the metal tube,
It is possible to prevent dripping (excessive polishing) near both ends of the metal tube.

According to the present invention, a highly accurate finish polished surface can be obtained by employing the above-described polishing apparatus and polishing method.
On the outer surface of the metal tube, a long scratch, that is, a typical hairline polished surface as a decorative polished surface is formed in the length direction, so that a material having an excellent decorative effect can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a polishing apparatus of the present invention is used for polishing a steel pipe will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing the overall concept of the polishing apparatus of the present invention. FIG. 2 is a side view showing the entire polishing apparatus of the present invention. FIG. 3 is a plan view showing an arrangement of a polishing tool and a metal tube in the apparatus of the present invention. FIG. 4 is a side view showing the arrangement of the polishing tool and the metal pipe of the apparatus of the present invention in a partial cross section orthogonal to the pipe axis. FIG. 5 is a side view showing the arrangement of the cart of the polishing tool and the water seal portion of the metal tube in a partial cross section in the apparatus of the present invention. FIG. 6 is a side view showing, in partial cross-section, a water seal portion at an end of the metal tube opposite to the water seal portion shown in FIG.

The polishing apparatus of the present invention will be described with reference to the conceptual diagram of FIG. The trolley 2 is reciprocated along both horizontal side surfaces of the long steel pipe 1 fixed at the processing position, and the side of the steel pipe 1 is polished by the pair of polishing tools 4 and 4 mounted on the trolley 2. Dummy materials 6 and 6 are attached to both ends 5 and 5 of the long steel tube 1, and the polishing materials 4 and 4 are first brought into contact with the dummy materials 6 and 6 at the start of polishing. To prevent the formation of streaks or sagging on the surface when the abrasive first strikes the vicinity of the end. The steel pipe 1 is divided and rotated by a predetermined angle by the steel pipe rotating motor 7 for each one-way traveling of the pair of polishing tools 4 and 4, and the outer peripheral surface of the steel pipe 1 is entirely rotated by the reciprocating traveling of the polishing tools 4 and 4 a plurality of times. Finish polishing. Before starting the polishing, the inner surface of the steel pipe 1
A necessary and sufficient amount of a cooling liquid such as water or cutting oil is injected.

Hereinafter, the polishing apparatus of the present invention will be described in detail with reference to FIGS. As shown in FIG. 2, a traveling rail 9 is installed on a base 8 below the steel pipe 1 horizontally positioned and fixed at the polishing position in parallel with the pipe axis of the steel pipe 1. The carriage 2 is placed on the traveling rail 9 so that the carriage 2 can reciprocate along the pipe axis of the steel pipe 1. As shown in FIG.
A pair of polishing tools 4 and 4 are attached with the rotation axis of the polishing tools 4 and 4 interposed therebetween with the steel pipe 1 interposed therebetween. As shown in FIG. 4, a receiving roll 10 for supporting the steel pipe 1 from its lower surface is provided on the carriage 2 at a position opposed to the polishing tools 4, 4.
0 is energized by the cylinder device 11. This receiving roll 1
With 0, the bending or the like of the steel pipe 1 due to its own weight can be corrected, and the center between the polishing tools 4 on both sides of the steel pipe 1 and the center of the steel pipe 1 can be accurately aligned. A polishing tool drive motor 12 is provided near the polishing tools 4 and 4 on the carriage 2,
Power is transmitted by a timing belt (not shown).

As shown in FIG. 5, one end of the steel pipe 1 is held by a metal pipe rotating shaft 13 and a connecting member 14 on the metal pipe rotating motor 7 side, and a bearing of a supporting device 16 fixed to a base 15 is provided. Thus, the metal tube rotating shaft 13 is rotatably supported. One end of the metal tube rotation shaft 13 is connected to the metal tube rotation motor 7 by an appropriate means, and transmits a rotational force to the steel tube 1. As shown in FIG. 6, the other end of the steel pipe 1 is gripped by a gripping member 17 and a connecting member 18, and rotatably supports the gripping member 17 by a bearing of a movable support device 20 that is movable on a base 19. . The movable support device 20 can be moved to the position indicated by the imaginary line according to the length of the steel pipe 1. The gripping member 17 does not need to be particularly connected to the rotation drive source.

An end face side of the steel pipe 1 of the metal pipe rotating shaft 13 is connected to the steel pipe 1 by a connecting member 14. The connecting member 14 has a rubber head 21 that is inserted into the inner surface of the end of the steel pipe 1 and fixed by water sealing. The rubber head 21 has several rubber rings 22, 22,... Between collars 23, 23,.
.. Are arranged, and when the screw 24 at one end is tightened, the collars 23, 23... Slide from both ends, the rubber rings 22, 22 are crushed and protrude into the inner surface side of the steel pipe 1, and Pressed against the inner surface to form a strong water seal.

A shaft 25 is provided on the side of the connecting member 14 opposite to the rubber head 21, and this shaft 25 is inserted into a hole of the metal tube rotating shaft 13. It is desirable that the connecting member 18 at the other end of the steel pipe 1 has the same structure.

The rubber members 21 are passed through the rubber heads 21 of the connecting members 14 and 18, and the rubber head 21 is inserted into the inner surface of the end of the steel pipe 1. At the same time, the dummy materials 6
Are fixed at 2, 22,...
.. Protrude toward the inner surface side of the steel pipe 1 and become larger, so that the centering of the end of the steel pipe 1 and the ends of the dummy materials 6 and 6 is inevitably performed. If a step is formed between the outer surface of the end of the steel pipe 1 and the outer surface of the end of the dummy material 6, it may cause poor polishing sagging near the end of the steel pipe 1 or damage to the polishing tool.

The steel pipe 1 is dividedly rotated by a constant angle by a metal pipe rotation motor 7. When the polishing in one way by the two polishing tools 4 and 4 is completed, the steel pipe 1 is rotated by one polishing width. After the rotation, the two horizontal polishing tools 4 are polished on both horizontal sides of the steel pipe 1 while running in reverse while rotating.
Alternatively, polishing may be performed only in one direction without polishing when returning. The rotation angle and the number of rotations by the metal pipe rotating motor 7 are set in the control device so that the entire peripheral surface of the steel pipe 1 is polished by repeating this reciprocating traveling polishing, and the polishing is performed fully automatically.

When the steel pipe 1 is run and polished, the abrasives of the polishing tools 4 and 4 are pressed against both side surfaces of the steel pipe 1 with a predetermined pressing force, and the polishing tools 4 and 4 are rotated and the rail 9 is rotated. Is driven at a constant speed in the pipe axis direction of the steel pipe 1. The adjustment of the polishing amount is performed by controlling the load current of the rotating motor of the flap wheels 4 and 4 with a meter relay. When the load is low, the load adjusting motor 26 is controlled, and the load adjusting means 27 controls the flap wheels 4 and 4. Press against steel pipe 1.

As the polishing tool 4, an elastic grindstone, a brush, or the like can be used. In order to prevent the occurrence of defective polishing due to heat-induced distortion and warpage, it is optimal to grind the steel pipe 1 linearly in the horizontal direction as described above and to use a flap wheel as the polishing tool 4. I understood that.

Flap wheels are well known as woodworking and metal abrasives. This is a rotary polishing tool in which a number of strip-shaped polishing cloths called flaps are radially arranged and attached to the outer periphery of a metal or plastic ring. The flap wheel is rich in flexibility due to its structure and is well adapted to the surface shape of the workpiece, so it is advantageous for grinding a curved surface.In general, the flap wheel rotates at high speed and can be expected to have a cooling effect, It has been reported that there is little burning and there is little clogging due to the gradual wear from the flap tip, and there is little change in the roughness of the finished surface from the beginning to the end of machining ("New grinding for practical use" Technology, page 65, December 1992, Ohmsha).

As described above, polishing with a flap wheel can be expected to have some cooling effect. However, when a long steel pipe, particularly a thin long steel pipe, is continuously reciprocated at a high speed, the wear is severe and the cooling effect is also high. Not enough. Of course, a method of polishing while spraying cooling water can be considered. In this case, although the cooling effect is enhanced, the cooling water supply / injection device and its control device are complicated, and the working environment is also deteriorated. As a result of intensive studies to solve this problem, the present invention has found that adopting a means of filling a large amount of cooling liquid inside the steel pipe and cooling it can continuously reciprocate a thin long steel pipe with a flap wheel at high speed. It has been found that it is extremely effective in polishing, and the above problem can be solved. for that reason,
After filling the steel pipe 1 with water, it is necessary to attach rubber heads 21 for water sealing to both ends of the steel pipe.

Preferably, one end of the steel pipe 1 is water-sealed with a rubber head 21 before being conveyed to the polishing position, a large amount of cooling water is injected by inclining the steel pipe 1, and the other end is also water-sealed with a rubber head 21. Later, the steel pipe 1 is transported to the polishing position and positioned and fixed. If the inner surface of the steel pipe 1 is completely filled with the cooling liquid, the cooling effect is maximized. When the injection amount of the cooling liquid was small and the air portion was large, it was found that the rubber head was pushed out or water leakage occurred due to gas expansion in the steel pipe during heavy polishing and long polishing. For this reason, the injection amount is preferably about 90% or more of the volume of the steel pipe. When cleaning or electrolytic polishing the inner surface of the steel pipe 1, an electrolytic solution or cleaning water may be used instead of water. Then, the working time can be reduced.

When the inner surface of the steel pipe is filled with a cooling liquid and water cooling is not performed, the receiving roll 10 supporting the lower part of the steel pipe 1 on the carriage 2
In particular, in the case of a steel pipe having an outer diameter of 100A to 125A, the bending of the steel pipe 1 occurs toward the upper part during polishing. When bending occurs, the center of the round surface of the flap wheel and the center of the polished surface on the side of the steel pipe are vertically displaced, and only the upper portion of the polished width on the side of the steel pipe is polished.

Fixing the flap wheels 4, 4 and fixing the steel pipe 1
It is also conceivable that the outer surface of the steel pipe 1 is polished in a spiral by moving the steel pipe 1 in the pipe axis direction while rotating, but in this case, the polished surface becomes helical, and the polishing heat is also generated in a helical manner. 1 causes thermal distortion,
Since both side surfaces of the steel pipe 1 are polished in a straight line at the same time, the temperature rise occurs linearly and evenly on both side surfaces of the steel pipe 1.
In combination with the cooling from the inside of the steel pipe and the function of the support roll on the lower surface of the steel pipe, the occurrence of thermal distortion and warpage of the steel pipe is suppressed.
Therefore, the polishing apparatus and the polishing method of the present invention have a thickness of 1.0 to 1.0.
Particularly suitable for finishing polishing of a long-walled stainless steel pipe having a length of about 10.0 mm.

Hereinafter, a specific example of a method for polishing the outer surface of a steel pipe using the apparatus of the present invention will be described. C: 0.021, Si: 0.
49, Mn: 0.62, P: 0.025, S: 0.00
1, Cr: 16.20, Ni: 13.50, Mo2.1
2, Al: 0.008, H: 0.0006, O: 0.0
A welded pipe having an outer diameter of 165 mm, an inner diameter of 159 mm, and a length of 4 m was manufactured using a high-purity stainless steel material comprising 033, Fe balance (% by weight). The steel pipe was filled with a cooling liquid before being transported to the polishing position. The filling amount was about 95% of the total volume inside the steel pipe.

Size of flap wheel is 355φ × 7
5 w (commercially available product A64-KW355 × 75-S) was used. The rotation speed of the flap wheel was 50 m / sec, the traveling speed of the bogie was 3.5 m / min, the rotation angle of the steel pipe was 36 degrees for each run, and the entire outer peripheral surface of the steel pipe was polished by a total of five reciprocating runs. Deformation and warpage due to thermal distortion of the steel pipe due to polishing heat during polishing were not observed, and a highly accurate hairline polished surface with an excellent decorative effect was formed.

[0028]

According to the apparatus of the present invention, generation of distortion due to polishing heat can be suppressed, high-speed finish polishing of a long metal tube can be performed, and the productivity is high and the practical effect is extremely large. Further, by polishing the inside of the metal tube with a cooling liquid, sufficient cooling power can be obtained without deteriorating the working environment, and highly accurate external surface finish polishing of the metal tube becomes possible. It is possible to provide an optimum stainless steel pipe as a process pipe in a clean room of a semiconductor manufacturing apparatus or the like which requires a finish polishing surface particularly.

[Brief description of the drawings]

FIG. 1 is a plan view showing the overall concept of a polishing apparatus according to the present invention.

FIG. 2 is a side view showing the entire polishing apparatus of the present invention.

FIG. 3 is a plan view showing a partial sectional view of an arrangement state of a polishing tool and a metal tube in the apparatus of the present invention.

FIG. 4 is a side view orthogonal to a tube axis showing a partial cross section of an arrangement state of a polishing tool and a metal tube of the apparatus of the present invention.

FIG. 5 is a side view showing, in a partial cross section, the arrangement of the cart of the polishing tool and the water seal portion of the metal tube in the apparatus of the present invention.

FIG. 6 is a side view showing, in partial cross section, a water seal portion at the end of the metal pipe opposite to the water seal portion shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tube 2 Cart 3 Running motor 4 Polishing tool 6 Dummy material 7 Metal tube rotating motor 10 Receiving roll 12 Drive motor 13 Metal tube rotating shaft 14 Connecting member 17 Holding member 18 Connecting member 20 Movable support device 21 Rubber head 26 Load adjustment Motor 27 Load adjusting means

Claims (7)

[Claims] In a polishing apparatus for an external surface of a long metal tube, a running rail is provided below a horizontally positioned metal tube in parallel with a tube axis of the metal tube, a bogie reciprocating on the running rail, and a bogie on the bogie. A pair of polishing tools placed on both horizontal side surfaces of the metal tube with the metal tube interposed therebetween, means for adjusting the pressing force of the polishing tool toward both horizontal side surfaces of the metal tube, and gripping both ends of the metal tube Means for rotating the metal tube at predetermined angles around the tube axis as a rotation axis. 2. The polishing apparatus according to claim 1, wherein a receiving roll for supporting a lower surface of the metal tube is provided on the carriage. 3. The polishing apparatus according to claim 1, wherein the polishing tool is a flap wheel attached with the rotation axis set in a vertical direction. 4. The polishing apparatus according to claim 1, wherein the means for gripping both ends of the metal tube has a member inserted into the end of the metal tube and sealed with water. 5. When the outer surface of a long metal tube is polished using the polishing apparatus according to claim 1, the inner surface of the metal tube is filled with a cooling liquid to prevent deformation of the metal tube due to polishing heat. A method for polishing an outer surface of a metal tube, characterized in that: 6. A polishing tool disposed opposite to both side surfaces of the metal tube is rotated to grind both horizontal side surfaces of the metal tube while rotating, and the metal tube is rotated by an angle corresponding to one polishing width for each run. The polishing method according to claim 5, wherein the outer surface of the metal tube is polished by repeating the polishing of the next run. 7. The polishing method according to claim 5, wherein a dummy material having the same outer diameter as the metal tube is loaded into both ends of the metal tube and polished.