AbstractOriginally developed back in the 1970's, the current generation of super-ferritic stainless steels have now become a popular choice for heat exchanger tubing.  When they were first developed, the goal was to have an alternative to titanium grade 2 in applications such as seawater and high chloride applications.  At that time, titanium was in was high priced and had long lead time, not unlike today.  However, over the last 10 years, the majority of the seawater capable stainless steel literature and usage has been focused on super-austenitic (6% and 7% Mo alloys) and super-duplex alloys.  While the performance of these alloys has been very good, today’s material nickel and molybdenum prices have driven the price of these alloys skyward. The power industry recognized the super ferritics and over 72,000,000 ft have be in use since 1980. With low nickel and moderate molybdenum content for excellent chloride resistance, this has driven a substantially increased use of the super-ferritic alloys.   This paper traces usage in power plant heat exchanger applications and compares properties such as corrosion resistance, mechanical and physical properties and compares them to the other seawater and MIC resistant grades.