Valves in an engine play some important role. The valves of a gasoline engine revolve at 3,600 revolutions per minute at an average. Different kinds of steel are used to produce different kinds of valve casting depending on the place and purpose of the valves. These types include martensitic steel and austenitic steel. These steels differ in their microstructure. This microstructure affects the hardness and strength as well as magnetic properties and corrosion resistance. Austenitic steels are non-magnetic while martensitic steels are magnetic.