Method for accurately quantifying flaw height of girth welding seam in submarine pipeline

Abstract

A method for accurately quantifying the flaw height of a girth welding seam in a submarine pipeline comprises the following inspection steps: (1) setting the depths of focuses of a diffractive ultrasonic emission probe and a diffractive ultrasonic receiving probe at a position of 2 / 3T of the wall thickness of the welding seam; (2) calculating the probe center distance; (3) performing sound velocity measurement, wedge delay calibrations, and detection system calibrations on sound velocity probes separately on a submarine pipeline sound velocity test block; (4) importing the ultrasonic time-of-flight diffraction channel parameter into the embedded flaw position of the girth welding seam in the submarine pipeline; (5) finding lateral wave signals and bottom surface reflected wave signals, and finding upper tip diffraction signals and lower tip diffraction signals from the embedded flaw; (6) comparing the wall thickness parameter of the girth welding seam of the submarine pipeline with the phase variation of the ultrasonic time-of-flight diffraction; (7) accurately quantifying the height of the embedded flaw; (8) carrying out comparative analysis on the macroscopic flaw section height and the height quantified by adopting the ultrasonic time-of-flight diffraction technology. The method has the advantages that the problem of low qualification rate of welding seams can be solved, the welding quality of the submarine pipeline can be ensured, and the submarine pipeline laying efficiency can be improved.

Description

technical field [0001] The invention relates to a quantitative method for girth weld defects of submarine pipelines, in particular to a method for quantifying the height of girth weld defects of submarine pipelines using diffraction time-difference ultrasonic testing. Background technique [0002] With the continuous acceleration of the development of modern industry, the development of deep sea oil and gas has become an inevitable trend, and the importance of offshore oil pipelines transporting deep sea oil and gas has also been highlighted. Therefore, the welding quality of offshore oil pipeline girth welds has become an increasingly concerned hot spot. [0003] The welding quality assessment of the girth weld of offshore oil pipelines has also changed from the initial simple defect length measurement to the combined assessment of the height and length of the defect, for example: engineering critical assessment (ECA) acceptance criteria, engineering critical assessment (EC...

AI Technical Summary

Problems solved by technology

[0004] At present, the fully automatic ultrasonic phased array testing method (AUT) of submarine pipeline girth welds usually adopts the partition method, which quantifies the defect height through the defect signal amplitude and the number of display areas in the strip chart. There is a large error in the highly quantitative size of buried defects, resulting in a high failure rate of welds, which in turn affects the normal laying efficiency of submarine pipelines

Images