Stainless steel acid or base, and the solution temperature. Uniform corrosion is typically easy to avoid because of extensive published corrosion data or easy to perform laboratory corrosion testing. However, stainless steels are susceptible to localized corrosion under certain conditions, which need to be recognized and avoided. Such localized corrosion is problematic for stainless steels because it is unexpected and difficult to predict. Acidic solutions can be categorized into two general categories, reducing acids such as hydrochloric acid and dilute sulfuric acid, and oxidizing acids such as nitric acid and concentrated sulfuric acid. Increasing chromium and molybdenum contents provide increasing resistance to
Austenitic stainless steel addition while 200 series stainless steels substitute manganese and nitrogen for nickel, though there is still a small nickel content. 300 series stainless steels are the larger subgroup. The most common austenitic stainless steel and most common of all stainless steel is Type 304, also known as 18/8 or A2. Type 304 is extensively used in such items as, cookware, cutlery, and kitchen equipment. Type 316 is the next most common austenitic stainless steel. Some 300 series, such as Type 316, also contain some molybdenum to promote resistance to acids and increase resistance to localized attack (e.g. pitting and crevice