Stainless Steel - Grade 308 (UNS S30800)

Topics Covered

Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations


Stainless steels are high-alloy steels which have high corrosion resistance when compared to other steels due to their high content of chromium. They are divided in to ferritic, austenitic, and martensitic steels based on their crystalline structure. Precipitation-hardened steels are another group of stainless steels. They are a combination of martensitic and austenitic steels.

The following datasheet gives more details about grade 308 stainless steel.

Chemical Composition

The following table shows the chemical composition of grade 308 stainless steel.

Element Content (%)
Iron, Fe 66
Chromium, Cr 20
Nickel, Ni 11
Manganese, Mn 2.0
Silicon, Si 1.0
Carbon, C 0.080
Phosphorous, P 0.045
Sulfur, S 0.030

Physical Properties

The physical properties of grade 308 stainless steel are displayed in the following table.

Properties Metric Imperial
Density 8 g/cm3 0.289 lb/in³

Mechanical Properties

The mechanical properties of annealed grade 308 stainless steel are outlined in the following table.

Properties Metric Imperial
Tensile strength 585 MPa 84800 psi
Yield strength (@ strain 0.200%) 240 MPa 34800 psi
Izod impact 135 - 165 J 99.6 - 122 ft-lb
Charpy impact 135 J 99.6 ft-lb
Elastic modulus 193 GPa 27993 ksi
Poisson's ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 50% 50%
Hardness, Brinell 139 139
Hardness, Knoop (converted from Rockwell B hardness) 155 155
Hardness, Rockwell B (converted from Rockwell B hardness) 80 80
Hardness, Vickers (converted from Rockwell B hardness) 153 153

Thermal Properties

The thermal properties of grade 308 stainless steel are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@ 0-100°C/32-212°F) 17.3 µm/m°C 9.61 µin/in°F
Thermal conductivity (@ 0-100°C/32-212°F) 15.2 W/mK 105 BTU in/hr.ft².°F

Other Designations

Other designations that are equivalent to grade 308 stainless steel include:

  • ASTM A167
  • ASTM A276
  • ASTM A314
  • ASTM A473
  • ASTM A580
  • DIN 1.4303
  • UNI 8 CrNi 19 10
  • JIS SUS 305
  • JIS SUS 305 J1
  • SAE 30308
  • SAE J405 (30308)

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