Advanced technology in automatic ultrasonic weld inspection of pipeline girth welds

摘要

The advantages of using ultrasonic inspection to detect certain weld defects over radiography have been understood for many years. However, inspection cycle time is a controlling factor in pipeline construction operations. The recent past has seen the entrance of automated ultrasonic technology into the harsh, demanding environment of pipelay operations but the success of automated ultrasonic inspection for pipeline construction welding has been limited to automated welding processes. The effectiveness of automated ultrasonic techniques used for manual pipeline welding inspection can be controversial. This is due to the infinite variability of the joint alignment and shape, which increases the chance of false calls significantly. The potential geometric problems arising from the variety of shapes produced from manual welding clearly set forth a challenge to anyone attempting to automate the process of ultrasonically inspecting pipeline welds produced by manual welding techniques within acceptable time parameters, ie less than five minutes per weld. This paper describes the use of immersion probes in arrays applied to inspect pipeline construction welds that have been made manually. It also examines the process by which this new system was developed and describes the challenges that had to be overcome to produce a cost-effective automated inspection system that not only produced consistently reliable results, but offered new advances to the industry.