GRADE 304 / 304L STAINLESS STEEL SPECIFICATION
Grade 304 / 304L stainless steel has a minimum of 18% chromium and 8% nickel. The only difference between them is the carbon content. Type 304 has a maximum carbon of 0.07% .Type 304L has maximum carbon of 0.030 %. This range of carbon in the steels affects the corrosion resistance. 304 / 304L is available in sheet, sheet coil, plate, plate coil, round bar, processed flat bar and tubular products for further manufacturing.
Applications
Grade 304 / 304L Stainless Steel is used in a wide variety of commercial and industrial applications, including:
- Construction material in building bridges, dams, roads, airports, canals, and buildings
- Nuts, bolts, screws, and other fasteners in the marine environment
- Food processing equipment, particularly in beer brewing, milk processing, and winemaking
- Architectural trim and molding
- Automotive and aerospace structural use
- Chemical containers, including for transport
- Heat exchangers
- Woven or welded screens for mining, quarrying & water filtration
304 Related Specs and Trade names
- EURONORM: 1.4301
- ASTM/ASME: UNS S30400
- BS 304S31
- AFNOR Z2 CN 18-10
- EN, DIN,UNI X5CrNi 18-10
- Grade 304
- Alloy 304
- Type 304
304L Related Specs and Trade names
- EURONORM: 1.4307
- ASTM/ASME: UNS S30403
- BS 304S11
- AFNOR Z2 CN 18-9
- EN, DIN,UNI X5CrNi 18-9
- Grade 304L
- Alloy 304L
- Type 304L
Corrosion Resistance
- 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.
- At times, grade 304L may show a lower corrosion rate than the higher carbon Alloy 304; otherwise, the 304 and 304L may be considered to perform uniformly in most corrosive environments.
- Grade 304L is preferred for use in environments sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones on susceptible alloys
Heat Resistance
- Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.
- Continuous use of 304 in the 800-1580°F range is not recommended if subsequent aqueous corrosion resistance is important.
- Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.
Welding Characteristics
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
Machinability
The use of chip breakers is advised since the chips can be stringy. Stainless steel work hardens rapidly, heavy positive feeds, sharp tooling, and a rigid set-up should be used.
Chemical Properties
| C | Mn | Si | P | S | Cr | Ni | |
| 304 | 0.07max | 2.0max | 1.00max | 0.045max | 0.03max | min: 17.5 max: 19.5 | min: 8.0 max: 10.5 |
| 304L | 0.03max | 2.0max | 1.00max | 0.045max | 0.03max | min: 17.5 max: 19.5 | min: 8.0 max: 10.5 |
Mechanical Properties
The properties quoted below are guideline figures only and should not be used for any design purposes.
| Grade | Tensile Strength ksi (min) | Yield Strength 0.2% ksi (min) | Elongation % | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
| 304 / 304L | 75 | 30 | 40 | 201 | 92 |
Physical Properties
| Density lbm/in3 | Thermal Conductivity (BTU/h ft. °F) | Electrical Resistivity (in x 10-6) | Modulus of Elasticity (psi x 10-6) | Coefficient of Thermal Expansion (in/in)/ °F x 10-6 | Specific Heat (BTU/lb/°F) | Melting Range (°F)) |
| at 68°F: 0.285 | 9.4 at 212°F | 28.3 at 68°F | 28 | 9.4 at 32 – 212° | 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 |