Type 304 Stainless Steelis the most widely used of the austenitic
(chromium/nickel) stainless steels. In the annealed condition it is
essentially non-magnetic and becomes slightly magnetic with the
application of cold work. Type 304L Stainless Steelis preferred in
welding applications to exclude the formation of chromium carbides
during cooling in the heat affected region of the weld. These
alloys represent an excellent combination of corrosion resistance
and fabricability.
Specifications
Type 304 ASTM A240, ASTM A666, AMS 5513 Type 304L ASTM A240, ASTM
A666, AMS 5511
Typical Applications
Chemical equipment and piping, heat exchanger components, dairy and
food handling equipment and utensils, cryogenic vessels and
components, architectural and structural applications exposed to
non-marine atmospheres
Chemical Composition: (Per ASTM A240)
Element | Type 304 | Type 304L |
Carbon | 0.07Max | 0.030 Max |
Manganese | 2.00Max | 2.00 Max |
Sulfur | 0.030 Max | 0.030 Max |
Phosphorus | 0.045 Max | 0.045 Max |
Silicon | 0.75 Max | 0.75 Max |
Chromium | 17.5 to 19.5 | 18.0 to 20.0 |
Nickel | 8.0 to 10.5 | 8.0 to 12.0 |
Nitrogen | 0.10 Max | 0.10 Max |
Mechanical Properties: (Per ASTM A240, A666)
Type | Yield Strength 0.2% offset (KSI) | Tensile Strength (KSI) | % Elongation(2" Gauge length) | Hardness Rockwell |
304 Ann | 30 min. | 75 min. | 40 min. | HRB 92 max. |
304 Hard | 75 min. | 125 min. | 12 min. | HRC 25-32 (typical) |
304 Hard | 110 min. | 150 min. | 7 min. | HRC 32-37(typical) |
304L Ann | 25 min. | 70 min. | 40 min. | HRB 92 max. |
304L Hard | 75 min. | 125 min. | 12 min. | HRC 25-32 (typical) |
304L Hard | 110 min. | 150 min. | 6 min. | HRC 32-37 (typical) |
Physical Properties: (annealed)
| | 304 & 304L |
Density (lb./ in^2) @ RT | | 0.29 |
Modulus of Elasticity in Tension (psi x 10^6) | | 28.0 |
Specific Heat (BTU/°F/lb.) | 32 to 212 °F | 0.12 |
Thermal Conductivity (BTU/hr/ft^2/ft) | 212°F | 9.4 |
| 932°F | 12.4 |
Mean Coefficient of Thermal Expansion (in. x 10^-6 per °F) | 32 to 212°F | 9.2 |
| 32 to 600°F | 9.9 |
| 32 to 1,000°F | 10.2 |
| 32 to 1,200°F | 10.4 |
Electrical Resistivity (micro ohms - cm) | at 70°F | 72 |
Melting Point Range (°F) | | 2550 to 2650 |
Oxidation Resistance - Continuous Service(°F) | | 1,650 |
Oxidation Resistance - Intermittent Service(°F) | | 1,500 |
Processing
Types 304 and 304L cannot be hardened by thermal treatment.
Annealing: Heat to1850o°F to 2050 °F and cool at sufficiently high
rates through 1500°F to 800°F to avoid precipitation of chromium
carbides. Stress Relief Annealing: Cold worked parts should be
stress relieved at 750°F for to 2
