Stainless steel Outokumpu's alloy 254 SMO, possess even greater resistance to chloride pitting and crevice corrosion because of their high molybdenum content (>6%) and nitrogen additions. They possess useful service to seawater applications. Ferritic stainless steels possess a ferrite microstructure like carbon steel, which is a body-centered cubic crystal structure and contain between 10.5% and 27% chromium with very little or no nickel. This microstructure is present at all temperatures, due to the chromium addition, and like austenitic stainless steels are not hardenable by heat treatment. They cannot be strengthened by cold work to the same degree as austenitic stainless steels. They
Stainless steel Hydrochloric acid will damage any kind of stainless steel, and should be avoided. All types of stainless steel resist attack from phosphoric acid and nitric acid at room temperature. At high concentration and elevated temperature attack will occur and higher alloy stainless steels are required. In general, organic acids are less corrosive than mineral acids such as hydrochloric and sulfuric acid. As the molecular weight of organic acids increase their corrosivity decreases. Formic acid has the lowest molecular weight and is a strong acid. Type 304 can be used with formic acid though it will tend to discolor the solution.