Stainless steel are magnetic like carbon steel. They are problematic to weld due to grain growth in the heat affected zone which reduces ductility and may result in cracks. Increasing chromium and molybdenum contents increase corrosion resistance as it does for austenitic stainless steels, however, this high alloying results in the precipitation of embrittling intermetallic phase upon welding. These microstructural problems due to welding restrict the use of ferritic stainless steels to very thin thicknesses and thus are not used in the construction of large heavy walled vessels and tanks, and structures like austenitic stainless steels. Common ferritic grades are: Type AISI
Marine grade stainless Marine grade stainless Marine grade stainless steel is a misunderstood description. There is no industry recognized definition for a marine grade stainless steel though it is routinely used by many end-users. In a marine environment it must be made clear as to whether the stainless steel is submerged in seawater or is simply near enough to the seashore such that it can be attacked by the chloride present in seawater by splashing or carried by onshore breeze. Chloride ions can cause localized corrosive attack (pitting and crevice corrosion) of susceptible stainless steels. When submerged a stainless steel with a PREN