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Materials of Construction - Metals - 304/304H SS
December 12, 2001
Introduction
Type 304 stainless
steel is the most versatile and one of the most widely applied of the 300 series stainless
steels. It has excellent forming and welding characteristics. The carefully
controlled analysis of Type 304 enables it to be deep drawn more severely than Types 301
and 302 without intermediate softening. This property has made this grade dominant
in the manufacture of drawn stainless steel parts. It is readily brake brake or roll
formed into a variety of other parts for application in the industrial, architectural and
transportation fields.
Type 304 also has
outstanding welding characterisitics. Post-weld annealing is not required to restore
the excellent performance of this grade in a wide range of midly corrosive conditions.
Chemical
Composition (wt% typical)
| |
304 |
304H |
| Nickel |
Ni |
8.0 - 10.5 |
8.0 - 10.5 |
| Chromium |
Cr |
18.0 - 20.0 |
18.0 - 20.0 |
| Manganese |
Mn |
2.0 max |
2.0 max |
| Iron |
Fe |
Balance |
Balance |
| Carbon |
C |
0.08 max |
0.04-0.10 |
| Phosphorus |
P |
0.045 max |
0.045 max |
| Sulphur |
S |
0.030 max |
0.030 max |
| Silicon |
Si |
0.75 max |
0.75 max |
| Nitrogen |
N |
0.10 max |
- |
Corrosion Resistance
Designations
UNS S30400
Alternate Names:
18-8 Stainless Steel
Specifications
| ASTM |
Tube and Pipe |
A430 |
|
Pipe - Welded |
A312, A409, A813, A814 |
|
Pipe - Seamless |
A312, A376 |
|
Tube - Welded |
A269, A688 |
|
Tube - Seamless |
A269, A271 |
|
Bars and Shapes |
A276, A479 |
|
Forgings |
A336, A473 |
|
Forged Flanges and Fittings |
A403 |
|
Plate and Sheet |
A240, A666 |
|
Strip |
A240, A666 |
|
Rod and Shapes |
A276, A479 |
Physical
Properties
| Electrical
Resistivity |
68°F |
72 microhm-cm |
| Coefficient of Thermal Expansion |
0-100°C (32-212°F) |
9.6 E-6 in/in °F |
| Magnetic Permeability |
|
1.02 |
| Themal Conductivity |
100°C
(212°F)
500°C (932°F) |
9.4 BTU/ft h °F
12.4 BTU/ft h °F |
Mechanical Properties
| Ultimate Tensile Strength |
579 MPa (84,000
psi) |
| Elongation in 50.8 mm (2 in.) |
55% |
| Yield Strength (0.2% offset) |
241 MPa (35,000
psi) |
| Hardness |
80 Rb
149 BHN |
| Impact Charpy |
135 ft lbs |
| Modulus of Elasticity (Tension) |
193,052 MPa (28,000,000 psi) |
Fabrication
To follow
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