What is the character and application of 304 stainless steel?
Alloy 304 a T-300 series stainless steel austenitic, which has a minimum of 18% chromium and 8% nickel. Type 304 has a maximum carbon of 0.07% . It is the standard “18/8 stainless” that is commonly found in pans and cooking tools. Alloy 304 is the most versatile and widely used alloy in the stainless steel family. Ideal for a wide variety of home and commercial applications, Alloy 304 exhibits excellent corrosion resistance and has a high ease of fabrication, outstanding formability. The austenitic stainless steels are also considered to be the most weldable of the high-alloy steels and can be welded by all fusion and resistance welding processes.
Specifications: UNS S30400
Alloy 304 Stainless Steel is used in a wide variety of home and commercial applications, including:
- Kitchen benches, sinks, troughs, equipment, and appliances
- Chemical containers, including for transport
- Food processing equipment, particularly in beer brewing, milk processing, and wine making
- Heat exchangers
- Architectural trim and molding
- Woven or welded screens for mining, quarrying & water filtration
- Automotive and aerospace structural use
- Nuts, bolts, screws, and other fasteners in the marine environment
- Construction material in large buildings
- Dyeing industry
- ASTM/ASME: UNS S30400 / S30403
- EURONORM: 1.4301 / 1.4303
- AFNOR: Z5 CN 18.09 / Z2 CN 18.10
- DIN: X5 CrNi 18 10 / X2 CrNi 19 11
- Resistance to moderately aggressive organic acids is a result of the 9 to 11% nickel that the 304 alloys contain.
- Resistance to corrosion in oxidizing environments is a result of the 18 to 19% chromium that the 304 alloys contain.
- The 304, 304L, and 304H may be considered to perform uniformly in most corrosive environments.
- Continuous use of 304 in the 800-1580°F range is not recommended if subsequent aqueous corrosion resistance is important.
- Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.
Properties of 304 Alloy
Excellent welding properties; post-weld annealing is not required when welding thin sections. Two important considerations in producing weld joints in the austenitic stainless steels are:
- avoidance of cracking
- preservation of corrosion resistance
Processing – Hot Forming:
- To forge, heat uniformity to 2100 / 2300 °F
- Do not forge below 1700 °F
- Forging can be air cooled without danger of cracking
Processing – Cold Forming:
- Its austenitic structure allows it to be deep-drawn without intermediate annealing, Making this the stainless steel grade of choice in the manufacturing of sinks, hollow-ware and saucepans.
- These grades work harden rapidly. To relieve stresses produced in severe forming or spinning, parts should be full annealed or stress relief annealed as soon as possible after forming.
- The use of chip breakers is advised since the chips can be stringy. Stainless steel work harden rapidly, heavy positive feeds, sharp tooling, and a rigid set-up should be used.of cut below the work-hardened layer resulting from the previous passes.
|304||0.07max||2.0max||0.75max||0.045max||0.03max||min: 18.0 max: 20.0||min: 8.0 max: 10.5||—|
|Grade||Tensile Strength ksi (min)||Yield Strength 0.2% ksi (min)||Elongation %||Hardness (Brinell) MAX||Hardness (Rockwell B) MAX|
(BTU/h ft. °F)
(in x 10-6)
(psi x 106
°F x 10-6
|at 68°F: 0.285||9.4 at 212°F||28.3 at 68°F||28||9.4 at 32 – 212°F||0.1200 at 68°F to 212°F||2500 to 2590|
|12.4 at 932 °F||39.4 at 752°F||10.2 at 32 – 1000°F|
|49.6 at 1652 °F||10.4 at 32 – 1500°F|