JP3251679B2 - Metallographic inspection system for pipe inner surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallographic structure inspection apparatus, and more particularly to a metallographic structure inspection apparatus suitable for remotely observing a metallographic structure such as an inner surface of a small diameter pipe.

[0002]

2. Description of the Related Art As one of inspection methods for evaluating the soundness of a metal material, there is observation of a metal structure using an optical microscope or the like, but when observing a metal surface structure for which a microscopic sample cannot be directly collected. In general, the surface to be observed is polished to a mirror surface, the surface is electrolytically corroded with a corrosive solution to reveal the structure, and then the surface structure is transferred to a replica film and observed. It is. However, these operations of polishing, electrolytic corrosion, and replica collection are mainly performed manually by workers, and there are variations due to individual differences among workers, and it is extremely difficult to apply to parts that cannot be reached. It is.

For example, as shown in FIG. 11, in a structure in which a number of long small-diameter pipes 3 approach each other and penetrate through a tube sheet 1 and are attached by welding, an attachment weld 2 of the pipe 3 is provided. There is a possibility that the metal structure of the nearby pipe 3 has changed due to the influence of welding heat. However, even if an attempt is made to observe the metal structure on the inner surface of the tube 3 for soundness evaluation, it is extremely difficult to observe the structure by replicating the metal structure by the above-described means because the worker cannot directly access the site. Was.

[0004]

According to the above-mentioned conventional inspection method, the soundness evaluation by sampling the metal structure of the material on the inner surface of a small-diameter and long tube that cannot be directly accessed by an operator due to its structure is not enough. It was extremely difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to easily obtain a replica of a metal structure on the inner surface of a small and long pipe that cannot be directly accessed by such an operator by remote control, and to easily evaluate the soundness of the pipe. An object of the present invention is to provide an apparatus for inspecting a metal structure of a pipe inner surface.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to insert a pipe surface polishing apparatus, a pipe surface electrolytic corrosion apparatus, and a replica sampling apparatus alternately from the pipe end into the inspection section and operate these apparatuses by remote control. This is achieved by polishing the surface to be inspected to a mirror surface, electrolytically corroding the surface to reveal a tissue, collecting a replica of the tissue, and observing the replica.

[0007]

The operation of the apparatus for collecting a replica in which the metal structure on the inner surface of the pipe has been transferred is as follows.

1) An in-tube surface polishing apparatus for polishing a surface to be inspected to a mirror surface has a rotary polishing tool which can be easily attached to and detached from the tip, and a long drive shaft is connected to the polishing tool. The surface to be inspected can be polished by rotating the drive shaft and the polishing tool with a motor provided outside the tube.

2) The pipe inner surface electropolishing apparatus for electrolytically corroding the surface to be inspected has a nozzle for injecting an electrode and an electrode corrosive liquid at a tip thereof, and a mechanism for sealing the electrolytic corrosive liquid. By inserting one from the end of the tube, sealing the lower part of the electrode and filling the surface to be inspected with the electrolytic corrosion liquid, by connecting one end of the electrode to the end of the tube and energizing one electrode inserted into the tube, Electrolytic corrosion of the surface to be inspected is possible.

3) A replica collecting apparatus for collecting a replica in which a metal structure on a surface to be inspected has been transferred has a nozzle for injecting a replica solvent at the tip and a mechanism capable of expanding and contracting in the axial direction of the tube. By attaching a replica film to this mechanism and inserting it from the end of the tube, and keeping the replica in close contact with the inner surface of the tube while spraying the solvent on the surface to be inspected, a replica of the surface to be inspected can be collected.

4) The above devices are alternately inserted into the surface to be inspected from the end of the tube, and these devices are operated by remote control to polish, electrolytically corrode, and collect replicas of the surface to be inspected. It is possible to observe the metal structure of the inspection surface.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus for inspecting metallographic structure on the inner surface of a pipe according to the present invention will be described with reference to FIGS. Note that, in the illustration, only the tube sheet 1, the welded portion 2, and the tube 3 are shown by hatching. The apparatus for inspecting the metallographic structure of the inner surface of the pipe is composed of a polishing apparatus for the inner surface of the pipe (FIGS. 1 and 2), an electrolytic corrosion apparatus for the inner surface of the pipe (FIGS. 3 and 4), and a replica collecting apparatus (FIGS. 5 to 6). Is done.

FIGS. 1 and 2 show an embodiment of a pipe inner surface polishing apparatus. The apparatus includes a drive motor 14 and a long flexible shaft 12 connected to the drive motor 14 for power transmission.
A spundle 7 serving as a rotating shaft connected to a flexible shaft 12 via a coupling 11, and a rotary polishing grindstone 5 for polishing an inner surface attached to a tip of the spundle 7 by a chuck 6. ing.

The spindle 7 has a guide tube 10 having a bearing 8 and a bearing 9 for supporting a rotating shaft therein.
And the flexible shaft 12 is covered with a flexible tube 13 for protection. Also,
A tube fixing flange 15 and a tube fixing ring 17 for fixing the flexible tube 13 to the tube 3 to be polished, and bolts 16, 18 and 1 for joining these.
There are nine.

FIG. 3 and FIG. 4 show an embodiment of a pipe inner surface electrolytic corrosion apparatus. This pipe inner surface electrolytic corrosion device has an energizing section,
It is composed of a chemical liquid seal part, a chemical liquid injection part, and a chemical liquid drain part.

The power supply section includes a power supply 35 for electrolytic corrosion, an electrode 21 provided at the tip of the apparatus, an insulator 25 for electrically insulating the electrode 21 from the tube 3, and electrically connecting these. And a joint 30 for the connection.

The chemical liquid seal section includes a gas cylinder 36 for gas (for example, air, nitrogen, etc.) for sealing a chemical liquid, a gas injection nozzle 24 and a seal rubber 23, a hose 32a and a joint 29 for connecting these, a gas And a valve 40 for controlling the supply of water.

The chemical solution injection section includes a gas cylinder 36 commonly used for gas for injecting the chemical solution and for sealing the chemical solution, an electrolytic corrosion liquid (for example, 10% oxalic acid) tank 37 and a cleaning liquid (for example, alcohol) tank 38. , A chemical liquid injection nozzle 20 at the tip, an electrolytic corrosion liquid injection pipe 26 and a cleaning liquid injection pipe 27 connected thereto, hoses 32b, 32c and a joint 29 for connecting these, and the supply of the electrolytic corrosion liquid and the cleaning liquid. It comprises valves 41 and 42 for controlling.

The chemical liquid drain section includes a vacuum device 44 for sucking the used chemical liquid, a chemical liquid drain tank 39, the overflow pipe 22 and the drain pipe 28 at the end, and hoses 32c, 32d and joints for connecting these. 29
And a valve 43 for controlling the drainage of the chemical solution.

The hose 32 and the electric wire 33 are connected to joints 29 and 30 at the insulator 25, respectively. These are housed in the guide tube 31. Under the guide tube 31, the hose 32 and the electric wire 33 are protected. Is covered with a flexible tube 34. Further, similarly to the pipe inner surface polishing apparatus, the flexible tube 34 is connected to the pipe 3 to be corroded.
There is a tube fixing flange 15 and a tube fixing ring 17 for fixing to the tube.

FIGS. 5 and 6 show an embodiment of the replica collecting apparatus. This replica collecting device includes a film pressing unit,
It is composed of a gas and solvent injection section.

The film pressing portion is a replica film 61
Film pressing rubber 51 as a cylindrical elastic body which is freely expandable and contractible in the direction perpendicular to the axis of the tube in order to press the inner surface of the tube, and a reinforcing plate 5 attached to the rubber 51 by dividing it in the circumferential direction.
2 and a film holder 53, an upper support plate 48, a lower support plate 49, and a guide ring 5 for holding them.
0 and a nut 47 for mounting the film 61.

The gas and solvent injection section includes a solvent and drying gas injection nozzle 45 provided at the end of the apparatus, an injection pipe 46 connected thereto, and a solvent for a replica solvent (for example, acetone, methyl acetate, etc.). The tank 62 and the gas cylinder 36 for the replica drying gas, the connector 54, the joint 55, the hoses 58 and 59 for connecting them, and the valves 63 and 6 for controlling the supply of the solvent and the drying gas.
4,65.

The hoses 58, 59 are connected to a joint 55 at a connector 54, and these are housed in a guide tube 56, and the hoses 58, 59 are provided below the guide tube 56.
Are covered by a flexible chirp 60 for protection. Further, similarly to the pipe inner surface polishing apparatus and the pipe inner surface electrolytic corrosion apparatus, there are a tube fixing flange 15 and a tube fixing ring 17 for fixing the flexible tube 60 to the pipe 3 to be inspected.

Using a pipe surface polishing apparatus, a pipe surface electrolytic corrosion apparatus, and a replica sampling apparatus shown in FIGS. 1 to 6, a pipe inner surface structure near a welded portion 2 of a pipe 3 attached to a pipe sheet 1 by welding is obtained. The procedure for observation and inspection is shown in FIGS. Hereinafter, this procedure will be described.

As shown in FIG. 7, 1. Polishing of the inner surface of the pipe
(1) Installation (replacement) of the grinding wheel, (2) Insertion and fixing of the device in the tube, (3) Start of the polishing (drive) motor, (4) Inner surface polishing, (5) Stop of the polishing motor, (6) From inside the tube It consists of a process of drawing out the device.

First, a tube fixing flange 15 to which one of two divided tube fixing rings 17 for fixing the tube inner surface polishing apparatus shown in FIGS. Is attached to the flange 4 at the lower end of the tube 3 by means of bolts 16.

Next, a relatively coarse polishing grindstone 5 is fixed to the tip of a spindle 7 of the pipe inner surface polishing apparatus by a chuck 6 (FIG. 7 (1)), and this is inserted into the pipe from the lower end of the pipe. The flexible tube 13 is fixed to the tube 3 by tightening the other tube fixing ring 17 with a bolt 18 in this state until the tip polishing portion reaches the inspected portion [(2) in FIG. 7].

When the drive motor 14 is operated in this state, the polishing grindstone 5 at the tip is rotated via the flexible shaft 12, the coupling 11, and the spindle 7, and the inner surface of the inspected portion is polished [(FIG. 3) and (4)].

After the polishing for a predetermined time is completed, the polishing (drive) motor 14 is stopped (FIG. 7 (5)), the tube fixing ring 17 is divided, and the flexible tube 1 is removed.
3 is withdrawn from the pipe [(6) in FIG. 7], the polishing grindstone 5 at the tip is replaced with a finer grindstone [(1) in FIG. 7], and the portion to be inspected is again subjected to the same procedure as above. By repeating the polishing, the inner surface of the tube of the inspected portion is mirror-finished.

After the part to be inspected is mirror-finished in this way, the part to be inspected is electrolytically corroded by the tube inner surface electrolytic corrosion apparatus shown in FIGS. As shown in FIG. 8, 2 & inner surface
Electrolytic corrosion includes (1) insertion and fixing of the device in the pipe, (2) seal in the pipe, (3) injection of electrolytic corrosion liquid, (4) electrolytic corrosion,
(5) Recovery of electrolytic corrosion liquid, (6) Injection and recovery of cleaning liquid,
Each step consists of (7) releasing the seal in the pipe and (8) extracting the device from the pipe.

First, with the valves 40, 41, 42 and 43 all closed, the electrolytic corrosion liquid and the cleaning liquid are poured into the tanks 37 and 38, respectively. Electrode 2 provided at the tip of the device
1 is inserted from the lower end of the tube into the inside of the tube until the tip electrode reaches the portion to be inspected, and in this state, the flexible tube 34 is fixed to the tube 3 in the same procedure as in the tube inner surface polishing apparatus described above. Here, an electric wire 33 (+ side) which is a counter electrode of the electrode 21 (− side) inserted into the tube is connected to the lower end of the tube [(1) in FIG. 8].

In this state, when the sealing gas is injected into the gas injection nozzle 24 from the tank 36 through the hose 32 a and the joint 29 by opening the valve 40, the seal rubber 23, which can freely expand and contract, expands and the pipe 3 is closed. The chemical solution is sealed in close contact with the inner surface [(2) in FIG. 8].

Next, by opening the valve 41,
The gaseous pressure causes the electrolytic corrosion liquid in the tank 37 to flow into the hose 3
2b, the joint 29, and the injection pipe 26 are injected into the electrode portion from the lower part of the electrode 21.
8 is gradually filled above [3] in FIG.

When the corrosion liquid is filled up to the upper end of the overflow pipe 22, the overflowed corrosion liquid is collected in the drain tank 39 through the overflow pipe 22, the joint 29, and the hose 32d, and the valve 41 is closed here. Thus, the electrode 2 provided at the tip of the device
While the part 1 is filled with the electrolytic corrosion liquid, the power supply 35 is turned on.
When N is set to N, a current is passed between the electrode 21 and the tube 3 for a predetermined time to perform electrolytic corrosion of the portion to be inspected [(4) in FIG. 8].

When the electrolytic corrosion is completed, the valve 43 is opened, and the drain pipe 28 provided below the electrode 21 is opened.
The used electrolytic corrosion liquid is collected in the drain tank 39 through the joint 29 and the hose 32e, and when the collection is completed, the valve 43 is closed again ((5) in FIG. 8).

Next, by opening the valve 42,
Due to the gas pressure, the cleaning liquid in the tank
c, through the joint 29, the injection pipe 27, and the injection nozzle 20, the portion to be electrolytically corroded is sprayed and the remaining electrolytic corrosive liquid is washed. At this time, the valve 43 is opened and cleaning is performed while the used cleaning liquid is collected in the drain tank 39. After the cleaning is completed, the valves 43 and 42 are closed [(6) in FIG. 8].

When the electrolytic corrosion of the portion to be inspected is completed in the above procedure, the valve 40 is closed to stop the gas pressurization, venting is performed, and the seal rubber 23 is contracted to release the seal [(7 in FIG. 7). )], And pull out the electrode 21 from the tube [(8) in FIG. 8].

After the portion to be inspected is electrolytically corroded in this way, a replica film to which the metal structure of the portion to be inspected has been transferred is sampled by the replica sampling device shown in FIGS.

As shown in FIG. 9, 3. Replica collection
(1) Installation of film on the device, (2) Insertion and fixing of the device in the tube, (3) Injection of film solvent, (4) Compression of film, (5) Supply of drying gas, (6) Drying of film ,
(7) Stop of drying gas, (8) Release of film pressure bonding,
(9) Pull out the device from inside the tube, (10) Remove the film,
(11) Consisting of each step of replica film observation.

First, the replica film 61 is put on the nut 47.
9 and the lower end of the replica film is attached to the film holder 53 [FIG.
(1)], this is inserted from the lower end of the pipe into the inside of the pipe until the replica reaches the inspected part, and in this state, the flexible tube 60 is fixed to the pipe 3 in the same procedure as the above-described pipe inner surface polishing apparatus. [(2) in FIG. 9].

By opening the valve 64 in this state, the solvent of the replica in the tank 62 is released from the hose 59, the joint 55, the injection pipe 46, and the nozzle 45 by the gas pressure.
Through which the liquid is sprayed onto the inspected portion and the inner surface of the tube is coated with the replica solvent [(3) in FIG. 9].

Next, by closing the valve 64 and opening the valve 63 at the same time, the hose 5 is opened.
8, gas is injected into the gap between the guide ring 50 and the film pressing rubber 51 through the joint 29 and the nozzle 24, and the film pressing rubber 51 expands. On the outer surface of the film pressing rubber 51, a reinforcing plate 52 and a film holder 53 divided into several parts in the circumferential direction are attached, and when the film pressing rubber 51 expands, the film holder 53 is pressed against the inner surface of the tube, Replica film 6
1 is brought into close contact with the portion to be inspected, and the metal structure of the portion to be inspected is transferred to the replica film 61 by the solvent previously applied [(4) in FIG. 9].

In this manner, the valve 65 is opened with the film 61 being in close contact with the inner surface of the tube, and the hose 59,
Through the joint 55, the injection pipe 46, and the nozzle 45, a gas for film drying is jetted to the portion to be inspected [(5) in FIG. 9], and the replica film is dried [(6) in FIG. 9].

After the drying for a predetermined time is completed, the valve 65
Is closed to stop the supply of the drying gas [(7) in FIG. 9]. Then, the valve 63 is closed to stop the gas pressurization for film pressing and venting. 51 is contracted [(8) in FIG. 9].

The metal structure of the portion to be inspected is transferred to the replica film 61 by the above procedure, and the replica film is peeled off from the inner surface of the tube by pulling out the apparatus from the tube and taken out of the tube [(9) in FIG. 9]. Then, the nut 47 is loosened to remove the replica film (FIG. 9 (10)), and the metal structure of the inspected portion can be observed by microscopic observation of the replica film (FIG. 9 (11)).

As shown in FIG. 7, the above operations are operations that can be performed easily and remotely, such as turning on / off the power, opening and closing valves, etc. For this reason, it is possible to easily collect a replica in which the metal structure on the inner surface of a small-diameter and long tube that cannot be directly accessed by an operator is transferred.

In this embodiment, i) since a flexible chirp is used for each device,
Even when the working space for inserting the device into the pipe from the pipe end is small, it can be easily inserted and withdrawn, and the device can be easily handled and stored even when the device becomes long. ii) In electrolytic corrosion, since electrolytic corrosion and the recovery of the cleaning liquid are possible, disposal of the waste liquid is easy. iii) In the replica collecting apparatus, since the film holder is divided into several parts in the circumferential direction, it is possible to simultaneously collect several replicas in the circumferential direction. iv) In the replica collecting apparatus, since gas for replica drying can be supplied, the replica film can be easily dried even in a place where drying is difficult, such as the inner surface of a small-diameter pipe, and nitrogen is used as the drying gas. The use of an inert gas such as that described above has an advantage that there is no possibility that an organic agent such as acetone as a film solvent explodes.

FIG. 10 shows another embodiment of the present invention. This embodiment shows an example of a replica collecting apparatus. Although the configuration and operation of the replica collecting apparatus shown in FIG. 5 are almost the same as those of the replica collecting apparatus shown in FIG. The connecting pipe 66 has a structure in which a tube fixing flange 67 is divided into two parts, and the tube fixing flange 67 is attached to the pipe 3 to be inspected by tightening it with bolts. The pipe end has no flange. It can be attached even in case.

The advantage of this embodiment is that the use of a rigid metallic connecting pipe makes it possible to secure higher dimensional accuracy at the replica sampling position and to improve the durability.

[0051]

According to the present invention, a replica in which the metal structure on the inner surface of the tube is transferred to a long small-diameter tube, which has been difficult to evaluate its soundness by observing the metal structure because a worker cannot directly approach the conventional structure. Can be easily collected and observed by remote control, which has a great effect on the evaluation of pipe soundness.

Further, by making the replica sampling operation into a device (mechanization), it is effective in labor saving, and polishing conditions (grinding wheel roughness, polishing speed, polishing time, etc.) previously adjusted to the conditions of the tube to be inspected by a test or the like. Optimum conditions such as electrolytic corrosion conditions (current, voltage, corrosion time, etc.) and replica sampling conditions (solvent injection amount, drying time, etc.) are not affected by individual differences among workers, and metal is always kept under constant conditions. Since organization observation is possible, it is effective in improving the reliability of soundness evaluation.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view showing one embodiment of a pipe inner surface polishing apparatus according to the present invention, and FIG. 1B is a sectional view taken along the line BB of FIG. 1A.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a longitudinal sectional view showing one embodiment of an electrolytic corrosion apparatus for a pipe inner surface according to the present invention.

4A is an enlarged cross-sectional view of a portion C in FIG. 3, and FIG. 4B is a cross-sectional view taken along line DD of FIG.

FIG. 5 is a longitudinal sectional view showing one embodiment of a replica collecting apparatus according to the present invention.

FIG. 6 is an enlarged sectional view of a portion E in FIG. 5;

FIG. 7 is a process chart showing a procedure of inner surface polishing in each apparatus of the present invention.

FIG. 8 is a process chart showing a procedure of inner surface polishing and corrosion in each apparatus of the present invention.

FIG. 9 is a process chart showing a replica collecting procedure in each apparatus of the present invention.

FIG. 10 is a longitudinal sectional view showing another embodiment of the replica collecting apparatus according to the present invention.

FIG. 11 is a perspective view showing a structural diagram of a tube and a tube sheet to which the present invention can be applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube sheet 2 Weld part 3 Tube 4 Flange 5 Polishing grindstone 6 Chuck 7 Spindle 10 Guide tube 11 Coupling 12 Flexible shaft 13 Flexible tube 14 Drive (polishing) motor 15 Tube fixing flange 17 Tube fixing ring 20 Chemical liquid injection nozzle 21 Electrode 22 Overflow pipe 23 Seal rubber 25 Insulator 26 Electrolytic corrosion liquid injection pipe 27 Cleaning liquid injection pipe 28 Drain pipe 29, 30 Joint 31 Guide pipe 32 Hose 34 Flexible tube 35 Power supply 36 Gas cylinder 37 Electrolytic corrosion liquid tank 38 Cleaning liquid tank 39 Chemical liquid drain tank 44 Vacuum device 45 Nozzle 46 Injection tube 47 Nut 48 Upper support plate 50 Guide ring 51 Film pressing rubber 53 Film holder 61 Replica film 62 Solvent tank 66 Connecting pipe

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takenori Shindo 6-9 Takaracho, Kure City, Hiroshima Prefecture Inside the Kure Factory (72) Inventor Katsuhiro Shigehiro 6-9 Takaracho Kure City, Hiroshima Prefecture Babcock Date Kure Factory Co., Ltd. (56) References JP-A-2-105036 (JP, A) JP-A-3-19952 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 1 / 28 G01N 33/20 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A method for inspecting and evaluating the soundness of a metal structure on an inner surface of a pipe, comprising: a nozzle provided at a tip portion ;
Separate the solvent for replica and the gas for drying separately on the wool
Has a hose for injection and below the nozzle
Provided, and a extendable and retractable mechanism in the axial direction of the nozzle, further the expansion and telescopic tubular elastic member by the fluid pressure to the outer surface of the mechanism, detachable replica film on the outer peripheral surface of the cylindrical elastic body A metallographic examination apparatus for an inner surface of a tube, comprising: a film holder for freely supporting the tube; and an injection tube for injecting a fluid into the cylindrical elastic body, and having a detachable replica sampling device inside the tube. 2. The film holder according to claim 1, wherein the film holder is divided into a plurality in the circumferential direction.
For metallographic examination of the inner surface of pipes. 3. A method for inspecting and evaluating the soundness of a metal structure on the inner surface of a pipe, comprising: (a) a rotary polishing tool which is detachably provided at a tip portion and which can be mounted inside the pipe; A pipe inner surface polishing apparatus connected to a drive source installed outside the pipe via a long drive shaft; (b) an electrode provided at the tip of the apparatus, a nozzle for injecting an electrolytic corrosion liquid, and electrolytic corrosion a sealing mechanism for pooling the liquid, and the tube surface galvanic corrosion and means for energizing between the electrodes and the tube, and nozzles provided in (c) tip replicon in said nozzle
To separately inject solvent and drying gas
Having a hose, and provided below the nozzle,
A extendable and retractable mechanism in the axial direction of the serial nozzle further and expansion and telescopic tubular elastic member by the fluid pressure to the outer surface of the mechanism, removably supporting the replica film on the outer peripheral surface of the cylindrical elastic body A metallographic examination apparatus for the inner surface of a tube, comprising: a film holder to be filled; and an injection tube for injecting a fluid into the inside of the tubular elastic body, and a replica sampling device detachably mounted inside the tube.