Sep 26 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
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)