Which method would you use to test for internal corrosion in a thick-walled pipe?

The use of ultrasonic testing (UT) is appropriate for evaluating internal corrosion in thick-walled pipes due to its ability to penetrate thick materials and provide accurate measurements of wall thickness. UT works by sending high-frequency sound waves into the material; if there are internal flaws, such as corrosion or erosion, the sound waves will be reflected back, allowing for the detection and characterization of these issues.

This method is particularly effective in assessing the extent of corrosion because it can measure material thickness and detect changes in the internal structure, providing critical information about the integrity of thick-walled pipes. Moreover, UT can be conducted without needing to remove the pipe from service, making it a practical choice for in-situ inspections.

In contrast, the other methods listed have limitations when it comes to detecting internal corrosion in thick materials. Visual inspection may miss internal flaws as it relies on surface observations. Magnetic particle testing is suitable for detecting surface and near-surface discontinuities in ferromagnetic materials but is ineffective for internal assessments. Dye penetrant testing is primarily used for surface-breaking defects and is not suitable for detecting internal corrosion in thick-walled pipes, as it cannot assess material thickness or internal conditions effectively.