What is corrosion mapping? Corrosion mapping uses ultrasonic testing to measure and record the thickness of an object due to corrosion.
There is different types of corrosion. Pitting corrosion is uneven and has many small holes called pits. Uniform corrosion is even across the test object. Exfoliation corrosion is corrosion that follows along layers of elongated grains. Inter-granular corrosion follows along grain boundaries of the object.
Corrosion mapping tells us if the test object is suitable for use. At the job I was at, the tank passed its corrosion test and is able to stay in use. It will need tested again in the future.
Manual corrosion mapping using a grid can be time consuming depending on the size of the crew and vessel being inspected. I plan on looking into ways to make the process quicker and easier, especially for a one person crew.