JPH09150318A - Sample gathering method from structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To gather a sample for evaluation of safety from partly a structure, by a device which can easily mounted in the structure in the case of working, with light reaction force in the working, can easily apply to the sample as a work object even when its size is changed, and can be applied to even a fillet welded part of the cylindrical structure. SOLUTION: A half moon-shaped groove 7 is previously cut in both sides of a position gathering a sample by a cutter 6 or grinding wheel, the groove in the both sides of the sample gathering position is cut so as to communicate by a device 20 of wire cut electric discharge machining system, the half moon- shaped sample 2 is gathered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for taking a test sample from a part of a steel structure for evaluating its safety.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a conventional example of a method for obtaining a boat-shaped sample (hereinafter simply referred to as a sample) from a steel structure. FIG. 5 shows a mechanical cutting type sample collecting method, in which a base material 01 is used by using a sword blade cutter 06 of a plate blade.
A V-shaped cut is made from both sides of the sample and a half-moon shaped sample 02a having a V-shaped cross section is cut out.

FIG. 6 uses a U-shaped electrode 03 and a bearing 0
The U-shaped electrode 03 is driven in a rope jumping motion while performing the forward and reverse servo-feeds about the pivot shaft 04 supported by 5, and a half-moon shaped sample 02b having a U-shaped cross section is taken.

[0004]

However, the conventional mechanical cutting sampling method shown in FIG. 5 has the following problems. (1) Since the cutting reaction force is large, it is necessary to support the cutting reaction force by fixing the cutting device itself to a structure by means such as welding when collecting a sample. (2) The base material to which this sampling method can be applied is limited to a structure having a relatively flat surface. It cannot be applied to fillet parts of welding.

(3) Since the shape of the groove remaining in the structure after the completion of sampling is V-shaped, it is necessary to smoothly grind the groove bottom when repairing it by welding, for example. is there.

Further, the conventional U-shaped electrode sampling method shown in FIG. 6 has the following problems. (1) It takes a lot of man-hours to manufacture the electrode into a U-shape. For example, in the electric discharge machining using pure water, expensive materials such as Ag-W are used for the electrodes, and the electrodes are manufactured by a wire cut electric discharge method or a mechanical cutting method. (2) In order to shorten the sampling time, it is necessary to make the thickness of the U-shaped electrode as thin as possible and to make the groove width as narrow as possible. Was needed.

The object of the present invention is to solve the above-mentioned problems, the device necessary for taking a sample can be easily attached to a structure, the reaction force at the time of processing is slight, and the size of the target sample is small. It is an object of the present invention to provide a method for taking a sample for evaluating the safety of a cylindrical structure or a part of the structure that can be applied to a fillet portion of welding, which can easily cope with the change.

[0008]

The structure sampling method of the present invention is a method for collecting a test sample from a part of a structure for evaluating the safety thereof, which comprises a cutter 6 or A half-moon shaped groove 7 is cut out on both sides of the position where the sample 2 is taken by a grinding wheel.
A half-moon-shaped sample 2 is sampled by cutting with a wire-cut electric discharge machine 20 so that the grooves on both sides of the sample collecting position communicate with each other.

[0009]

1 is a perspective view of a method of taking a sample from a structure according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a method of processing the cutting groove in FIG. In FIGS. 1 and 2, 1 is a base material, 2 is a sample, 6 is a cutter, 7 is a cutting groove, 8 is a tip guide roller, 9 is an electric discharge machining head, 9a is a roller column, 10 is a wire electrode, and 11 is an upper guide. Reference numeral 12 is a wire bobbin, 13 is a wire winding roller, and 20 is a wire-cut type electric discharge machine.

A method of obtaining a sample from a structure will be described below with reference to FIGS. A wire-cut type electric discharge machine 20 as shown in FIG. 1 is used in order to reduce the cutting reaction force when taking a sample. Two left and right roller columns 9a are attached to the machining head 9 of the electric discharge machine 20, and tip guide rollers 8 are arranged at the ends of both columns. The wire electrode 10 is supplied from the wire bobbin 12 via the upper guide roller 11 between the two tip guide rollers 8 and is wound by the wire winding roller 13.

Prior to wire electric discharge machining, as shown in FIG. 2, a cutter 6 is attached to a portable electric tool, and a half-moon shaped cutting groove 7 is formed in the base material 1 in advance. The cutting grooves 7 are cut out on both sides of the sample 2 as shown in FIG. 1, and the groove width is finished so that the roller column 9a around which the wire electrode 10 is wound around the guide roller 8 at the tip portion can smoothly pass. When cutting the groove, it is not necessary to support the cutting reaction force by welding or the like.

The wire electrode 10 for electric discharge machining is supported by two tip guide rollers 8 mounted on roller columns 9a inserted into the cutting grooves 7 on both sides of the sample, and feeds the machining head 9 in the vertical direction and back and forth. By combining and driving the directional feeds, wire electrical discharge machining of the surface of the bottom of the sample is advanced.

Pure water is usually jetted and supplied from a machining liquid supply device (not shown) to the machining portion by wire discharge. During this machining, the machining reaction force received by the electric discharge machining device 20 is extremely small, and the structure can be supported by a method such as vacuum suction or magnet attraction.

The disc-shaped cutter 6 shown in FIG. 2 (which may be a disc-shaped grinding wheel) is also applicable to the cylindrical or columnar base material 1 as shown in FIG. The sample 2 can be collected in the same manner as the method shown in FIG. Further, in the same manner, it is possible to collect the sample 2 including the welding defect portion 15 from the welding bead 14 of the base material 1 of the fillet welded structure shown in FIG.

[0015]

The features and effects of the method of sampling a structure according to the present invention will be described below. (1) Disk-shaped cutter 6 attached to a portable power tool
By using (or a grinding wheel), it is possible to efficiently cut out half-moon shaped cutting grooves 7 on both sides of the sample. (2) Electric discharge machining head 9 equipped with a column 9a that can be inserted into the cutting groove and that can move smoothly in the groove
Wire-cut type electric discharge machine 20 with built-in
The bottom of Sample 2 is processed by.

(3) Since the machining reaction force received by the electric discharge machining device is extremely small, the machining device can be supported only by adhering it to a structure. (4) The bottom surface of the sample 2 has a smooth curved surface processed by the wire electrode 10. (5) Even if the size of the sample 2 changes, it can be easily dealt with by changing the pitch of the groove 7 cut out by the cutter 6 and adjusting the pitch of the tip guide roller 8 of the electric discharge machining head 9. .

(6) It is possible to collect a very small sample without using a specially shaped electrode, and the repair work in the subsequent process can be easily performed. Further, it is possible to collect the sample 2 from a cylindrical or columnar structure or the sample 2 from a fillet welded structure. (7) Since the wire cutting electric discharge machining method is used for all parts except the cutting groove 7, for example, the wire diameter is 0.2 to
With 0.4 mm, the machining groove width could be narrowed such that the expansion margin was 0.1 to 0.2 mm.

[Brief description of the drawings]

FIG. 1 is a perspective view of a method of collecting a sample from a structure according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a method for processing the cutting groove in FIG.

FIG. 3 is a perspective view of an application example of the sample collecting method according to the embodiment of the present invention to a cylindrical structure.

FIG. 4 is a perspective view of an application example of the sample collecting method according to the embodiment of the present invention to a fillet welded structure.

FIG. 5 is a side sectional view of a conventional mechanical cutting type sampling method.

FIG. 6 is a perspective view of a conventional U-shaped electrode type sampling method.

[Explanation of symbols]

1 ... Base material, 2 ... Sample, 6 ... Cutter, 7 ... Cutting groove, 8
... tip guide roller, 9 ... electrical discharge machining head, 9a ... roller support, 10 ... wire electrode, 11 ... upper guide roller,
12 ... Wire bobbin, 13 ... Wire winding roller, 20
… Wire-cut electric discharge machine.

Claims (1)

[Claims] 1. A method for collecting a test sample from a part of a structure for evaluating its safety, which comprises a method for collecting a sample (2) by a cutter (6) or a grinding wheel in advance. A half-moon shaped groove (7) is carved out on both sides, and a wire-cut electric discharge machining system (20)
The method for collecting a sample from a structure is characterized in that the half-moon shaped sample (2) is sampled by cutting so that the grooves on both sides of the sample collecting position communicate with each other.