Ultrasonic phased array inspection method for hot melt welding joint of gas polyethylene pipeline

Abstract

The invention discloses an ultrasonic phased array inspection method for a hot melt welding joint of a gas polyethylene pipeline. The method includes the following steps: according to the thickness ofa gas polyethylene pipeline to be inspected, selecting a phased array probe to connect a phased array ultrasonic flaw detector, and connecting the phased array probe to a water wedge block; placing the water wedge block on a reference test piece made of a polyethylene material for ultrasonic phased array calibration; smoothly placing the water wedge block on a hot melt welding joint on the polyethylene pipeline, and compressing high rebound sponge by applying pressure to ensure that the high rebound sponge matches the hot melt welding joint and the polyethylene pipeline; setting a focusing rule of an ultrasonic phased array, and slowly injecting water into the water wedge block to fill the entire water wedge block; and moving the water wedge block to obtain an inspection image and performanalysis. According to the scheme of the invention, a coupling agent between the wedge block and a workpiece is the water, high economic benefits can be realized, and moreover, the method is applicable to polyethylene pipes with a certain curvature, and can be applied in the on-site inspection of the polyethylene pipes.

Description

technical field [0001] The invention relates to the technical field of ultrasonic phased arrays, in particular to an ultrasonic phased array detection method for hot-melt welding joints of gas polyethylene pipelines. Background technique [0002] At present, most urban gas pipelines use high-density polyethylene pipes (PE80 or PE100). As the service life of the pipelines increases, the failure cases gradually increase. The main reason for the failure of polyethylene pipelines is the failure of welded joints. The welded joints of polyethylene pipes mainly include hot-melt welded joints and electric fusion welded joints. For hot-melt welded joints, visual inspection can only see the surface of the polyethylene pipe, but cannot know the specific conditions of the internal defects of the pipe. Ultrasonic testing has a good effect on some defects such as larger holes and cracks, but it is not ideal for some process defects such as unfused. Therefore, there is still a lack of no...

AI Technical Summary

Problems solved by technology

[0003] The main problems of ultrasonic phased array detection in the detection of hot-melt joints of polyethylene pipes are that the acoustic impedance of polyethylene materials is smaller than that of plexiglass wedges; the sound velocity of longitudinal waves in ordinary plexiglass wedges is greater than that in polyethylene materials The speed of sound; the attenuation coefficient of sound waves in polyethylene materials is about 10 times that of steel; polyethylene pipes will produce inner and outer flanging during welding, which will affect the detection

Images