Ultrasonic Guided Wave for Chilled Water Pipelines Corrosion Testing

Corrosion defects in central air-condition chilled water pipelines were tested using ultrasonic guided wave. Reflection signals were marked and suspected defects were verified after removal of the insulating layer. The corrosion rate of the defects in the circumferential direction was calculated, and different factors affecting the reflection signals were studied. The results show that the ultrasonic guided wave method can test and locate the corrosion defects rapidly. Guided wave modes transform and wave packets disperse in the branch and adjustable tube, so the testing results in the areas behind such structures are invalid. Guided wave weakens rapidly due to the corrosion layer's absorb leading to the decline of reflection signals along pipelines.