304 stainless steel is the most widely used stainless steel, containing 18-20% Cr and 8-10.5% Ni, and also known as 18-8 stainless steel. SS 304 is non-magnetic under annealing conditions, but after cold working (such as stamping, stretching, bending, rolling), part of the austenite structure may be converted into martensite and therefore weakly magnetic. Type 304 has good resistance to atmospheric corrosion and oxidation. The high nickel-chromium alloy content gives it excellent corrosion resistance and is widely used in the food industry as a standard food grade stainless steel.

There are several variants of 304 grade stainless steel, such as ultra-low-carbon version type 304L, nitrogen-containing version 304N, 304H with improved creep performance, and type 302 with higher carbon content. The second most widely used 316 grade stainless steel, compared with 304, reduced chromium content, increased nickel content, and added 2-3% molybdenum. The addition of molybdenum can enhance the resistance to pitting and crevice corrosion caused by chloride. Therefore, 316 SS is widely used in marine applications.