304 Stainless Steel

SAE 304 stainless steel is the most common stainless steel. The steel contains both chromium (between 18–20%) and nickel (between 8–10.5%)^[1] metals as the main non-iron constituents. It is an austenitic stainless steel. It is less electrically and thermally conductive than carbon steel and is essentially 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.^[1]

The composition was developed by W. H. Hatfield at Firth-Vickers in 1924 and was marketed under the trade name “Staybrite 18/8”.^[2]

It is specified by SAE International as part of its SAE steel grades. Outside of the US it is commonly known as A2 stainless steel, in accordance with ISO 3506 for fasteners.^[3] In the commercial cookware industry it is known as 18/8 stainless steel. In the unified numbering system it is UNS S30400. The Japanese equivalent grade of this material is SUS304. It is also specified in European norm 1.4301.