The pitting corrosion test of stainless steel with ferric chloride is a rapid test method to test the pitting corrosion resistance and crevice corrosion resistance of stainless steel and related alloys. The boiling ferric chloride is used as corrosive agent to evaluate stainless steel and other metals by weight loss method.

Pitting corrosion is a kind of corrosion form which is concentrated on the surface of metal and develops in depth. It has a great hidden danger, that is, destructive. For example: in petroleum, chemical industry, marine, once pitting corrosion occurs, it will cause pipe wall perforation, so that a large number of oil and gas and other media leakage, and even cause fire or more serious accidents. Pitting corrosion will lead to very small weight loss of stainless steel and other metals. Due to the small area, the local corrosion rate will be very fast. Once pitting corrosion occurs, the equipment and pipeline wall will be perforated in a short time, leading to accidents. Because the pitting corrosion is small and can be covered by corrosive substances, it is difficult to measure and inspect the pitting corrosion. It is a most destructive and potential corrosion form.

Therefore, the spot corrosion test of ferric chloride is a necessary test standard for stainless steel and other metals when they leave the factory. Only stainless steel and other metals that have been tested can ensure their safety in use.