Method for detecting thickness reduction of heated surface tube of boiler

Abstract

The invention discloses a method for detecting the thickness reduction of the heated surface tube of a boiler. The method comprises the following steps: 1, obtaining the frequency dispersion curve ofLamb waves under the standard wall thickness d1 of the heated surface tube in the boiler to be detected; 2, obtaining an optimal detection frequency f1 according to a group velocity frequency dispersion curve in the frequency dispersion curve; 3, obtaining the phase velocity cp of the Lamb waves in a phase velocity frequency dispersion curve, corresponding to the optimal detection frequency f1 instep 2, and determining the incidence angle alpha of an acoustic beam according to the Snell's law; 4, allowing a variable angle probe to connect with an ultrasonic flaw detector and detect at the optimal detection frequency f1 according to the incidence angle alpha of the acoustic beam in step 3, and acquiring echo signals in an S0 mode and an A0 mode; and 5, obtaining the transit time differencebetween S0 mode echo and A0 mode end face echo waves according to the echo signals, and calculating the thickness reduction of the heated surface tube according to the transit time difference. The method has the advantages of convenience and fastness in completing of detection, and increase of the reliability of a detection result.

Description

technical field [0001] The invention belongs to the field of non-destructive testing of containers, in particular to a method for detecting the thinning amount of tubes on the heating surface of boilers. Background technique [0002] The safe operation of the heating surface of boilers in thermal power plants is the most important work of metal technical supervision in thermal power plants. For high-parameter and large-capacity units, especially ultra-critical (ultra)critical units, the units are affected by soot blowers and flue gas during operation, and the heating surface tubes are prone to blowing damage and thinning. At present, the inspection of the boiler heating surface is mainly based on macroscopic inspection. This method has low inspection efficiency and requires a high sense of responsibility for the inspectors, and there will be missed inspections in places that cannot be seen. Therefore, this inspection method is very important for the stable operation of the b...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the defects of low inspection efficiency in the existing detection method of boiler heating surface tube thinning, and the detection results of ultrasonic thickness gauge detection have random and accidental problems, it is necessary to provide a boiler heating surface tube The detection method can complete the detection conveniently and quickly. Based on the Lamb wave detection, it overcomes the randomness and contingency of the detection results brought about by the midpoint measurement method of the existing ultrasonic thickness gauge, and improves the reliability of the detection results.

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