JPH0815112A - Stress corrosion crack monitor - Google Patents

Abstract

PURPOSE:To obtain a stress corrosion crack monitor having a function for automatically detecting and recording the rupture of a test piece. CONSTITUTION:A pressure gas is encapsulated in a test piece 2 loaded under a corrosive environment. The pressure gas is monitored through a pressure switch 7 and when the pressure of the gas is varied due to rupture of the test piece, the pressure variation at that moment of time is recorded on a recorder 9 through the pressure switch 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stress corrosion cracking monitoring device used for predicting deterioration of a steam turbine or the like.

[0002]

2. Description of the Related Art Stress corrosion cracking of a material is a phenomenon in which the material is cracked under static stress in a corrosive environment and may cause serious damage to equipment. Therefore, it is useful to insert a monitoring test piece into the environment of the operating equipment and monitor the stress corrosion cracking of the material loaded in the corrosive environment in order to know the stress corrosion cracking of the equipment at an early stage. . Therefore, as a conventional test piece for monitoring,
For example, a test piece of the type in which a plate-shaped test piece 12 as shown in FIG. 2 is bent and tightened with a screw 13 has been used. In this test piece, the corrosion state is known by inserting the test piece into the environment of the operating equipment, periodically taking it out and observing the fracture state of the test piece.

[0003]

However, in the conventional method of monitoring the stress corrosion cracking, the test piece is intermittently taken out of the equipment and the fracture condition of the test piece is manually observed. The cost of the survey is high, and the survey is intermittent, so that there is a drawback that the true time when the test piece breaks cannot be known. Therefore, in order to solve the problems of the prior art, the present invention will provide a stress corrosion cracking monitoring device equipped with an automatic detection and recording function of test piece breakage, which is simple and can be detected at low cost in real time. It is what

[0004]

For this reason, the present invention is provided with a test piece in which a pressure gas is sealed and a pressure switch capable of detecting the pressure gas in the test piece. It is equipped with a device for detecting and recording the time, and this is used as a means for solving the problem.

[0005]

According to the present invention, when the test piece is broken, the gas sealed in the center hole leaks, and the pressure in the pipe changes. The pressure switch detects the pressure change at this time, opens or closes the circuit, and records the output from the pressure switch in the recording device, whereby the test piece breakage can be automatically detected in real time.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a stress corrosion cracking monitoring apparatus as one embodiment of the present invention. In FIG. 1, 1 is an environmental chamber provided in an actual plant for exclusive use in a stress corrosion cracking test, 2 is a test piece, and 2 is a frame 3
Both ends are fixed by nuts 4a and 4b, and static stress is applied by these nuts. In addition,
A hole 14 is provided on the side surface of the frame 3 so that the corrosive environment is different from that of the test piece 2.
It acts on the outer surface of the. The test piece 2 has a central hole 5 whose one end is not penetrated, and a pipe 6 is connected to the other end of the central hole 5 via a seal 11. The pipe 6 is taken out of the environment chamber 1 through the seal 11 and connected to the pressure switch 7.
A pressure gas is previously sealed in the pipe 6 and the central hole 5 through a valve 8. Further, the pressure switch 7 is connected to the recorder 9, and the pressure switch 7 is activated when a predetermined pressure change occurs, and the recorder 9 records the time.
As described above, according to this device, when the test piece 2 is broken due to corrosion, the gas sealed in the center hole leaks and a pressure change occurs. Therefore, by detecting this pressure, the breakage of the test piece 2 is detected in real time. can do.

[0007]

As described in detail above, according to the present invention, when the monitoring device is attached to the equipment for monitoring, the gas in the center hole of the test piece leaks when the test piece cracks, At this point, the pressure switch is activated and the test piece breakage time is recorded, so that the test piece breakage can be detected in real time. Further, since the device is simple, a low cost device can be realized. Further, since the crack of the test piece can be detected with certainty, the accuracy of the monitoring test can be improved and other excellent effects can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a corrosion crack monitoring device according to an embodiment of the present invention.

FIG. 2 is a side view showing an example of a conventional stress corrosion cracking monitoring test piece.

[Explanation of symbols]

 1 Environmental Chamber 2 Specimen 3 Frame 4a, 4b Nut 5 Center Hole 6 Pipe 7 Pressure Switch 8 Valve 9 Recorder 10, 11 Seal 12 Plate Specimen 13 Screw 14 Hole

Claims (1)

[Claims] 1. A device comprising a test piece filled with a pressure gas and a pressure switch capable of detecting the pressure gas in the test piece, for detecting a change in gas pressure due to breakage of the test piece and recording the time. A stress corrosion cracking monitoring device characterized by being installed.