SAE 304 stainless steel

SAE 304 stainless steel, also known as A2 stainless steel (not the same as A2 tool steel) or 18/8 stainless steel, European norm 1.4301, is the most common stainless steel. The steel contains both chromium (usually 18%) and nickel (usually 8%) metals as the main non-iron constituents.^[1] It is an austenite steel. It is not very electrically or thermally conductive and is non-magnetic. It has a higher corrosion resistance than regular steel and is widely used because of the ease in which it is formed into various shapes. It contains 17.5–20% chromium, 8–11% nickel, and less than 0.08% carbon, 2% manganese, 1% silicon, 0.045% phosphorus, and 0.03% sulfur.^[2]

The composition was developed by W. H. Hatfield at Firth-Vickers in 1924 and was marketed under the trade name "Staybrite 18/8".^[3]

Corrosion resistance

304 stainless steel has excellent resistance to a wide range of atmospheric environments and many corrosive media. It is subject to pitting and crevice corrosion in warm chloride environments and to stress corrosion cracking above about 60 °C. It is considered resistant to potable water with up to about 200 mg/L chlorides at ambient temperatures, reducing to about 150 mg/L at 60 °C.

Application

304 stainless steel is used for a variety of household and industrial applications such as screws,^[4] machinery parts, car headers, and food-handling equipment. 304 stainless steel is also used in the architectural field for exterior accents such as water and fire features.

References