Surface wave detection method for circumferential cracks in the inner wall of special-shaped pipes with small diameter and depth ratio

Abstract

The invention discloses a small-depth-diameter-ratio special-shaped pipe inner wall circumferential crack surface wave detection method and belongs to the field of ultrasonic non-destructive testing.The small-depth-diameter-ratio special-shaped pipe inner wall circumferential crack surface wave detection method is innovatively characterized by arranging surface wave sensors in the radial direction of the end portion of a special-shaped pipe, and according to the reflecting and transmission characteristics of surface waves on the internal edge of the end portion, reasonably selecting detectingfrequency and detecting the circumferential cracks of the inner wall of the special-shaped pipe through axial surface waves transmitted to the inner wall of the pipe. According to the small-depth-diameter-ratio special-shaped pipe inner wall circumferential crack surface wave detection method, the contact surfaces between the sensors and the end portion of the pipe are flat, and the coupling state of the sensors and the end portion of the pipe is irrelevant to the curvature of the inner wall of the pipe, so that applicability of the surface wave sensors can be greatly improved, and rapid andefficient detection can be achieve. The small-depth-diameter ratio special-shaped pipe inner wall circumferential crack surface wave detection method achieves detection of circumferential grooves different in size in the inner wall of a small-depth-diameter-ratio pipe and accordingly proves the effectiveness.

Description

technical field [0001] The invention belongs to the field of ultrasonic nondestructive testing, and in particular relates to a detection method for circumferential cracks on the inner wall of special-shaped pipelines with small diameter and depth ratio based on surface wave detection technology. Background technique [0002] Casing head spools and tubing head spools and other special-shaped pipes with small (diameter) and depth (degree) ratios are important connectors in oil production equipment, supporting the weight of other components in oil production equipment and bearing a certain internal pressure. The health status directly affects the safe and reliable operation of oil production. The production process of these special-shaped pipes usually includes a forging process. During this process, there is a large stress inside the forging, which is prone to defects. After the inner hole is formed by machining, there may be circumferential cracks on the inner wall of the spe...

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Problems solved by technology

However, for small-diameter-depth-ratio special-shaped pipes, the curvature of the inner wall is large. When detecting special-shaped pipes of different sizes, it is necessary to adjust the contact surface between the sensor and the pipe to obtain a good coupling condition, which leads to poor applicability of a single sensor. powerful

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