Objective This article mainly introduces three methods for measuring pitting depth: metallographic method, micrometer method and microscopy method, and discusses their differences in different pitting conditions and their influence on the measurement results. Methods Pitting pits on the surface of carbon steel and stainless steel were respectively measured by using these three measuring methods. and the measured results were analyzed and discussed. Results By comparing the measurement results, we can see that the metallographic method is more accurate, but it is destructive. The micrometer method is only suitable for wide and shallow pitting pits. The microscope method is not only suitable for wide and shallow pitting pits, but also for the small pit bottom. Conclusion (1) For wide and shallow pitting pits, metallographic method, micrometer method and microscopic method are applicable and the results are consistent; (2) For the small pitting pit at the bottom, metallography and microscopy are more suitable and the results are consistent; (3) When the corrosion depth is measured by metallographic, microscope and micrometer methods, the thickness reduction caused by uniform corrosion should be taken into account and the results should be corrected, especially in the case of more obvious uniform corrosion.

metallography method  /  micrometer method  /  microscopy method  /  pitting depth