Rapid elimination method for shaft forging flaw detection phantom wave

An ultrasonic and phantom technology, applied in the use of sound waves/ultrasonic waves/infrasonic waves to analyze solids, process detection response signals, instruments, etc., can solve the problems of increasing losses, misjudgments, etc., to reduce losses, improve misjudgments, and improve flaw detection accuracy degree of effect

Inactive Publication Date: 2017-08-18
HANGZHOU STEAM TURBINE CASTING & FORGING
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  • Abstract
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Problems solved by technology

In order to solve the misjudgment that is easy to occur in the ultrasonic flaw detection of shaft forgings by conventional methods and incre

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  • Rapid elimination method for shaft forging flaw detection phantom wave

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Example Embodiment

[0029] Example one

[0030] When using a 2~2.5M probe to detect shaft forgings radially, phantom waves may appear on the oscilloscope of the ultrasonic flaw detector. At this time, when the parameters of the ultrasonic flaw detector remain unchanged, only the 4~5M probe needs to be replaced. It is enough to detect the displayed part. If the wave F on the oscilloscope disappears, the wave F is a fantasy wave; otherwise, the wave F is a defective wave, which means that the shaft forging is defective and should be replaced or repaired in time.

Example Embodiment

[0031] Embodiment two

[0032] In general flaw detection, adjust the sound path of the first bottom wave B1 to the eighth grid of the oscilloscope. When it is found that the wave F is displayed before the first bottom wave B1, adjust the sound path knob of the ultrasonic flaw detector to increase the sound path to 1680mm. If the wave F on the oscilloscope disappears, the wave F is a fantasy wave; otherwise, the wave F is a defective wave, indicating that the shaft forging is defective and should be replaced or repaired in time.

[0033] The present invention is a method for quickly eliminating phantom waves from ultrasonic flaw detection for shaft forgings. When a signal wave F that is uncertain whether it is a fantasy wave or a defect wave occurs, the repetition frequency of the flaw detection instrument is adjusted, the frequency of the probe is replaced, and the detection sound path is increased. Any one of the three detection methods can be detected to determine whether the wav...

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Abstract

The present invention belongs to the technical field of shaft forging flaw detection, and discloses a rapid elimination method for a shaft forging flaw detection phantom wave. The rapid elimination method is based on phantom wave production factor analysis, is obtained through practice summarization, and comprises the following three operation parts: adjusting the repetition frequency of a flaw detection instrument, changing the frequency of a probe, and increasing a detection sound path, wherein ultrasonic wave flaw detection is performed again through one of the three operation parts, it is determined that the wave F is a phantom wave if the wave F disappears, and it is determined that the wave F is a defect wave if the wave F still exists. According to the present invention, the detection can be performed by using any one of the three detection methods if the appearing signal wave F being the phantom wave or the defect wave cannot be determined, such that the problem of the easy misjudgment of the conventional method is improved, the unnecessary loss is reduced, and the flaw detection accuracy of the shaft forging is improved.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of flaw detection of shaft forgings, in particular to a method for quickly eliminating phantom waves in ultrasonic flaw detection of shaft forgings. [0003] 【Background technique】 [0004] Shaft forgings, such as engine main shafts, rotor shafts of steam turbines and generators, and diesel engine crankshafts, etc., operate at high speeds and bear medium and high loads. In order to ensure the normal operation of shaft forgings, their defects must be detected. The defects of shaft forgings can be divided into external defects and internal defects. Ultrasonic flaw detection is the most suitable method for internal defects so far. At present, for the flaw detection of shaft forgings, the longitudinal wave straight probe contact method is usually used for flaw detection. Generally, flaw detection is carried out according to JB1581 in China and ASTM SA-388 in foreign countries. On the workpiece body, u...

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Application Information

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IPC IPC(8): G01N29/44G01N29/04
CPCG01N29/04G01N29/44G01N2291/023G01N2291/0289
Inventor 鲍俊乐周黎明
Owner HANGZHOU STEAM TURBINE CASTING & FORGING
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