Comparison on pipeline welds and integrity through different electromagnetic NDT techniques

Eddy Current Testing (ECT), Eddy Current Pulsed Thermograpgy (ECPT) and Magnetic Barkhausen Noise (MBN) are effective Non-Destructive Testing and Evaluation (NDT&E) techniques that have been applied for material characterization and defects inspection of conductive components. The common point of these three technologies is that they are all employed to test and evaluate the integrity of the workpiece based on the electromagnetic principle. However, different inspection techniques and material properties may produce different inspection effects. This paper is one international joint study on defect and weld of pipelines by using different electromagnetic methods on several samples and to study the relationship among mechanical properties of welds, defects and different inspection techniques. After a brief outline of theoretical studies and the influence of materials and defects on the response, a series of experiments have been conducted and quantitative studies on these methods have been conducted. It indicates that ECT and ECPT have similar results for the same mechanical properties of welds. The EC signal and MBN signal increase at defects and welds region. However, for different test pieces of the same mechanical properties, their capability of detection is complementary.