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
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|
The tables below list 18-8 stainless steel mechanical properties including yield strength, tensile strength, elongation and hardness, etc.
|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|
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.
- 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)|
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|
|Standard||Type||Standard||Grade (Steel Number)||Standard||Grade (ISO Number)||Standard||Grade||Standard||Grade||Standard||Grade||Standard||Grade||Standard||Grade||Standard||Grade|
|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;
06Cr19Ni10 (New designation)
022Cr19Ni10 (New name)