Case Study: Metal Corrosion on Stainless Steel

Metal corrosion analysis is an important tool in preventing corrosion. Metal corrosion is a process by which metals deteriorate because of chemical and/or electrochemical reaction with their environment. Corrosion prevention can be an issue of health and safety. Metal parts make a variety of structures, including bridges and buildings. According to The American Galvanizers Association (AGA), there are several types of corrosion:

Galvanic
Pitting
Microbial
High temperature
Crevice

THE PROBLEM: A stainless steel panel was showing discoloration and pitting that suggested it had gone through a corrosion process. Our client requested that we confirm the discoloration was due to corrosion and identify the cause of the corrosion.

THE ANALYSES: Visual inspection of the panel indicated widespread pitting and corrosion (Figure 1). A portion of the panel was cut and analyzed using a scanning electron microscope (Figure 2). The analysis indicated chromium and iron are the base metals of the alloy, and there was abundant chlorine present.

An optical image of the pitting

An electron image of a pit with corrosions

THE OUTCOME: MVA’s results showed that the pitting corrosion on the steel panel was caused by chloride attack. The manufacturer was able to trace the source of the chlorine and fixed the corrosion problem.