Method for performing weld-joint ultrasonic detection through frequency-phase compound coding excitation signal

Abstract

The invention discloses a method for performing weld-joint ultrasonic detection through a frequency-phase compound coding excitation signal, relates to the technical field of welding structure quality detection, and aims at solving the problem that in existing weld-joint ultrasonic detection, a satisfactory detection result cannot be obtained when a frequency coding signal or a phase coding signal is separately adopted for excitation. The method comprises the following steps that the frequency-phase compound coding signal is edited; the frequency-phase compound coding signal is guided into a signal generator; the signal generator sends out a frequency-phase compound coding pulse signal; the excitation signal is loaded into an ultrasonic detection probe after passing through a power amplifier; the probe converts the electric signal into a sound signal to be loaded into a detected workpiece; ultrasonic waves are transmitted in the detected workpiece and reflected when the ultrasonic waves encounter an interface; the probe receives the sound signal and converts the sound signal into an electric signal; an ultrasonic acquisition card receives the electric signal; mismatched filtering is performed on an echo signal and the phase coding signal to obtain an intermediate result; matched filtering is performed on the intermediate result and the windowed frequency coding signal to obtain a final detection result. The method is applied to the field of welding quality detection.

Description

technical field [0001] The invention relates to the technical field of welded structure quality detection, in particular to a method for ultrasonic detection of weld seams by using frequency-phase composite coded excitation signals. Background technique [0002] Welded structures are widely used in industrial production, but defects often occur during the welding process. When a welded structure with defects is used as a load-bearing or pressure-bearing structure, it is not conducive to safe production. Therefore, non-destructive testing of welded structures is required. In the field of non-destructive testing, ultrasonic testing is widely used in the detection of internal defects of welds. In the ultrasonic inspection of welds, it is necessary to be able to find defects and accurately measure the size and position of defects, so it is necessary to improve the signal-to-noise ratio and time resolution of ultrasonic inspection results of welds. A higher signal-to-noise rati...

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Problems solved by technology

[0004] In order to solve the problem that satisfactory detection results cannot be obtained when the frequency-coded signal is used alone or the phase-coded signal is used alone in the existing ultrasonic detection of welds, the present invention proposes the use of frequency-phase composite coded excitation signals Methods of Ultrasonic Testing of Weld Seams

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