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
Duplex stainless steel Duplex stainless steel Duplex stainless steels is the most recent family of stainless steels. They are called duplex (or austenitic-ferritic) grades because their metallurgical structure consists of two phases, austenite (face-centered cubic lattice) and ferrite (body centered cubic lattice) in roughly equal proportions. They are used for their good mechanical properties in the as-cast (and therefore as-welded condition) and/or their excellent corrosion resistance properties (particularly to stress corrosion cracking). They tend to be divided in three sub groups: Grade 1.4462 which has been the grade initially developed. and reperesents the "mid-range" of properties and is perhaps the most used today