Surface wave detection method for longitudinal defect on outer surface of small-diameter tube

Abstract

The invention discloses a surface wave detection method for a longitudinal defect on the outer surface of a small-diameter tube. The method comprises the following steps: 1), cleaning the outer surface of a to-be-detected small-diameter tube and coating the small-diameter tube with a coupling agent; 2), arranging a surface wave probe on the to-be-detected small-diameter tube; 3), selecting a comparison test cube of the to-be-detected small-diameter tube and cutting a groove in the surface of the comparison test cube of the to-be-detected small-diameter tube; 4) using the comparison test cube of the to-be-detected small-diameter tube to perform horizontal line calibration on an ultrasonic instrument; 5), adjusting the detection sensitivity of the ultrasonic instrument; 6), adjusting the ultrasonic instrument to enable the propagating direction of surface waves emitted by the surface wave probe to be perpendicular to a bus-bar of the to-be-detected small-diameter tube, and using the surface wave probe for scanning on two side surfaces of the to-be-detected small-diameter tube sequentially; determining that a surface longitudinal defect with the depth larger than A mm is formed in the current detection position of the to-be-detected small-diameter tube when reflected waves with the wave amplitude higher than B% are fully displayed on a display screen of the ultrasonic instrument. According to the surface wave detection method, detection of the longitudinal defect on the surface of the small-diameter tube can be realized, and the defect can be positioned accurately.

Description

technical field [0001] The invention relates to a surface wave detection method, in particular to a surface wave detection method for longitudinal defects on the outer surface of a small-diameter pipe. Background technique [0002] Small-diameter pipes such as heating surface pipes for power plant boilers are often manufactured by cold drawing (rolling) technology. If the quality control is not good, longitudinal defects will appear on the surface of the steel pipe. The existence of defects will bring safety hazards to the operation of the boiler. In order to ensure the safe operation of small-diameter pipes, it is very important to strengthen the effective inspection of small-diameter pipes. [0003] The shape of the small-diameter tubes on the heating surface used in power plant boilers is U-shaped tubes or serpentine tubes. The distance between the two tubes is very small, and the detection space is limited. If eddy current, magnetic particle, and penetrant testing tech...

AI Technical Summary

Problems solved by technology

At present, the ultrasonic surface wave detection technology is mostly used for the surface quality detection of relatively flat components. In the power industry, it is mostly used for the detection of steam turbine rotor R arcs and blades. The relevant literature does not mention the surface wave detection technology of small-diameter tubes. Therefore, It is necessary to develop a new surface wave detection technology for small-diameter pipes to ensure that the detection quality of the outer surface of small-diameter pipes in service meets the requirements

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