Grade 304 stainless steel is excellent in 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 60 °C approximate.
Grade 304 is considered to be resistant to potable water up to approximately 200 mg/L chlorides at ambient temperatures, reducing to approximately 150 mg/L at 60 °C. Grade 304 is a standard "18/8" stainless.
It is the most versatile and most widely used stainless steel available, even though a wide range of alternatives are available; and has excellent forming and welding characteristics. The balanced austenitic structure of Grade 304 enables it to be severely deep drawn without intermediate annealing.
This means that this grade steel is dominant in the manufacture of drawn stainless parts such as sinks, hollow-ware and saucepans. For these applications, it is common to use special 304 DDQ or Deep Drawing Quality variants.
Grade 304 can be readily braked or roll-formed into a variety of components for applications in the industrial, architectural, and transportation fields. It also has outstanding welding characteristics.
Post-weld annealing is not required when welding thin sections. Grade 304L, the low carbon version of 304, does not require post-weld annealing and is therefore extensively used in heavy gauge components like over about 6mm.Grade 304H with its higher carbon content is used in applications at elevated temperatures. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.
These properties are specified for flat rolled product like stainless steel furniture, plate, sheet, and coil in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.
Grade 304 has good oxidation resistance in intermittent service to 870 °C, and in continuous service to 925 °C. Continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important.
