Type 304 stainless steel is not magnetic, according to Bosun Supplies Company. This steel, along with other 300-series stainless steel types, is an austenitic stainless steel. Unlike ferritic steels, austenitic steels do not respond to magnetic fields the way metal usually does.
While any steel must contain 50 percent iron, as noted by The National Board of Boiler and Pressure Vessel Inspectors, the other elements that comprise a particular alloy type can greatly affect its properties. Type 304 steel is non-magnetic due to its relatively high concentration of chromium and nickel and the specific lattice structure of the chemical bonds between those elements.