18/8 Stainless Steel Properties, Yield Strength, Composition, Density, Tensile Strength, Hardness
What is 18/8 Stainless Steel
18/8 stainless steel is also konwn as 304 stainless steel, it refers to the chemical composition of steel containing 18% chromium (Cr) and 8% nickel (Ni). The steel containing 18% chromium and 8% nickel includes 304 and its variants 304L, 304N and 304LN. 18/8 steel is the most widely used material, has excellent corrosion resistance in mild environments, and has good weldability and mechanical properties.
18/8 Stainless Steel Properties
The tables below list the 18/8 stainless steel properties including chemical composition, physical and mechanical properties. For full datasheet and specification, please view AISI 304, 304L.
Chemical Composition
18-8 stainless steel composition is given in table below.
| Chemical Composition, % | ||||||||||
| ASTM | AISI (UNS) | C, ≤ | Si, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr | Ni | N, ≤ | Product |
| ASTM A240/A240M | 304 (UNS S30400) | 0.07 | 0.75 | 2.00 | 0.045 | 0.030 | 17.5-19.5 | 8.0-10.5 | 0.10 | Plate, Sheet, and Strip |
| ASTM A276A/276M | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-11.0 | – | Bars and Shapes | |
Mechanical Properties
The tables below list 18-8 stainless steel mechanical properties including yield strength, tensile strength, elongation and hardness, etc.
| Mechanical Properties | |||||||||
| ASTM Type | AISI (UNS) | Tensile Strength, (MPa), ≥ | Yield Strength, ≥ (MPa) at 0.2% Offset | Elongation in 50 mm (%, ≥) | Reduction of Area, %, ≥ | Brinell Hardness, (HBW) ≤ | Rockwell Hardness, (HRBW) ≤ | Product | Condition |
| ASTM A240/A240M | 304 (UNS S30400) | 515 | 205 | 40 | – | 201 | 92 | Plate, Sheet, and Strip | – |
| ASTM A276A/276M | 515 | 205 | 40 | 50 | – | – | Bars and Shapes | Hot finished | |
| 620 | 310 | 30 | 40 | – | – | Cold finished, Dia ≤ 12.7mm | |||
| 515 | 205 | 30 | 40 | – | – | Cold finished, Dia. > 12.7mm | |||
Physical Properties
18-8 stainless steel physical properties including density, melting point, magnetic, specific heat capacity, electrical resistivity, modulus of elasticity (elastic modulus), thermal diffusivity, thermal conductivity and coefficient of thermal expansion.
Notes:
- 10-6·K-1 = 10-6/K
- 1 Ω·mm²/m = 1 μΩ·m
- 1 g/cm3 = 1 kg/dm3 = 1000 kg/m3
- 1 GPa = 1 kN/mm2
- 1 MPa = 1 N/mm2
| 18-8 Steel Physical Properties | |
| Density, g/cm3 (lb/in3) | 7.93 (0.286) |
| Melting point, °C (°F) | 1400-1450 (2550-2650) |
| Specific heat capacity, J/kg·K (Btu/lb ·°F) | 500 (0.12) at 20 °C (68 °F) |
| Electrical resistivity, μΩ·m | 0.72 at 20 °C (68 °F) |
| Conductivity, %, IACS | 2.5 |
| Magnetic permeability | 1.02 (Approximate) |
| Elastic modulus (Modulus of Elasticity), GPa (106 psi) | 193 (28) |
| Thermal diffusivity, mm2/s (in2/s) | 3.84 (0.006) |
| Thermal conductivity, W/m·K (Btu/ft·h·°F) | 16.2 (9.4) at 100 °C (212 °F) |
| 21.5 (12.4) at 500 °C (932 °F) | |
| Coefficient of thermal expansion (CTE), 10-6/K (μin./in·°F) | 17.2 (9.6) at 0-100 °C (32-212 °F) |
| 17.8 (9.9) at 0-315 °C (32-600 °F) | |
| 18.4 (10.2) at 0-538 °C (32-1000 °F) | |
Applications
18/8 stainless steel is widely used in petroleum & chemical industry, metallurgical machinery, aerospace industry, food processing equipment, instruments, household appliances and hardware manufacturing industries.
18/8 steel is made into a great many intermediate products such as steel sheet & plate, steel tube & pipe, steel bar & flat, rod & wire, etc.
Final products such as all kinds of kitchenware, tableware, medical device, machinery and parts, wire mesh, filter, architectural and decorative metal products, etc.
| 18-8 stainless steel equivalent grade | |||||||||||||||||
| US | European Union | ISO | Japan | China | Australia | India | Rusia | Korea | |||||||||
| Standard | Type | Standard | Grade (Steel Number) | Standard | Grade (ISO Number) | Standard | Grade | Standard | Grade | Standard | Grade | Standard | Grade | Standard | Grade | Standard | Grade |
| AISI SAE; ASTM A276/A276M; ASTM A240/A240M; | 304 (UNS S30400) | EN 10088-1; EN 10088-2; EN 10088-3 | X5CrNi18-10 (1.4301) | ISO 15510 | X5CrNi18-10 | JIS G4303; JIS G4304; JIS G4305; | SUS304 | GB/T 20878; GB/T 1220; GB/T 3280 | 0Cr18Ni9; 06Cr19Ni10 (New designation) | ||||||||
| 304L (UNS S30403) | X2CrNi18-9 (1.4307); X2CrNi19-11 (1.4306) | X2CrNi19-11 (4306-304-03-I) | SUS304L | 00Cr19Ni10; 022Cr19Ni10 (New name) | |||||||||||||
