General Properties
Alloy 330 (UNS N08330) is an austenitic nickel-iron-chromium
alloy developed to provide excellent resistance to carburizing
and oxidizing atmospheres at elevated temperatures.
With a nickel content of 34 to 37 percent, the alloy
remains highly resistant to both chloride stress corrosion
cracking and embrittlement from the precipitation of
sigma phase.
The high nickel and chromium content provides
excellent resistance to both oxidation and carburization.
The oxidation resistance is also enhanced by the silicon
content of the alloy. The alloy performs well under
cyclic conditions of heating and cooling and in alternate
carburizing and oxidizing atmospheres.
Alloy 330 offers a high level of corrosion
resistance, particularly to oxidation, carburization,
and nitridation. It is readily fabricated using standard
procedures for stainless steels and nickel alloys. The
alloy is used extensively in elevated temperature atmospheres
where resistance to the combined effects of thermal
cycling and carburization is required.
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Applications
- Chemical and Petrochemical Processing
- Cracked ammonia components
- Petrochemical furnace parts
- Petrochemical waste remediation units
- Heat exchangers
- Flares
- Ore Processing
- Perlite systems and equipment
- Power Generation
- Boiler fixtures
- Gas turbine components
- Thermal Processing
- Heat-treat furnace containers
- Heat-treat furnace components
- High temperature fans
- Salt pots
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Standards
| ASTM.......................... |
B 536 |
| ASME.......................... |
SB 536 |
| AMS ........................... |
5592 |
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Chemical
Analysis
Typical Values (Weight %)
| Ni |
Cr |
Fe |
C |
Si |
Mn |
P |
S |
| 34.0 - 37.0 |
17.0 - 20.0 |
Balance* |
0.08 max. |
0.75 - 1.50 |
2.0 max. |
0.030 max. |
0.030 max. |
*Alloy predominates remaining composition.
Other elements may be present only in minimal quantities.
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Physical
Properties
Density:
0.292 lb/in3
8.08 g/cm3
Specific Heat:
0.11 BTU/lb/°F (32 - 212°F)
460 Joules/kg/°C (0 - 100°C)
Magnetic Permeability:
1.02 at 70°F/20°C (RT)
Linear Coefficient of Thermal Expansion
Thermal and Electrical Properties
| Temperature |
Thermal Conductivity |
Electrical
Resistivity |
| °F |
°C |
Btu-in/ft2-h-°F |
W/m-°C |
ohm-circ mil/ft |
mW-m |
| 75 |
24 |
86 |
12.4 |
612 |
1.017 |
| 400 |
204 |
108 |
15.6 |
649 |
1.079 |
| 800 |
427 |
134 |
19.3 |
688 |
1.144 |
| 1200 |
649 |
162 |
23.4 |
721 |
1.199 |
| 1600 |
871 |
198 |
28.6 |
744 |
1.237 |
| 1800 |
982 |
216 |
31.2 |
749 |
1.245 |
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Mechanical
Properties
Typical Room Temperature Mechanical Properties,
Mill Annealed
| Ultimate Tensile Strength,
ksi (MPa) |
80
- 85 (552 - 586) |
| 0.2% Offset Yield Strength, ksi (MPa) |
30 - 43 (207 -
296) |
| Elongation in 2 inches (50mm), %
|
40 - 45 |
| Hardness, Rockwell B |
70 - 85 |
High Temperature Mechanical Properties
Tensile Properties of Annealed Material
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Corrosion
Resistance
Alloy 330 provides a high level of corrosion
resistance, particularly to oxidation, carburization,
and nitridation. In aqueous environments the chromium
content of 330 provides resistance to oxidizing conditions,
while the nickel content enhances resistance to reducing
conditions. The alloy’s high nickel content also
makes it highly resistant to chloride stress corrosion
cracking and sigma phase embrittlement.
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Oxidation
Resistance
Alloy 330 has good oxidation resistance and
resists scale formation up to about
2000°F (1095°C). Any scale which is formed is
tightly adherent, particularly under
cyclic conditions of heating and cooling.
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Carburization
Resistance
The alloy’s 35 percent nickel content
and silicon addition contribute greatly to its excellent
resistance to carburization. In alternating carburizing
and oxidizing atmospheres, Alloy 330 exhibits excellent
resistance to the “green rot” phenomenon.
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Nitridation
Resistance
Alloy 330 exhibits good resistance to nitrogen-containing
atmospheres where the oxygen content is low. It is used
extensively in components handling cracked ammonia.
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Heat
Treatment
Alloy 330 is an austenitic alloy that cannot
be hardened by thermal treatment. Only cold working
will contribute to increased room temperature strength.
For most high temperature applications, 330 is not annealed
after cold forming or welding.
If a full anneal is required, it should
be carried out in a temperature range of 1870-2050°F
(1020-1120°C). Water quenching provides the optimum
creep resistance, but rapid air cooling to below 800°F
(425°C) may also be utilized.
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Fabrication
Alloy 330 is readily hot or cold formed using
the standard procedures for austenitic stainless steels
and nickel alloys. The work hardening rate of the alloy
is comparable to austenitic stainless steels.
Forming at room temperature is suggested.
If hot working is required, the alloy should be heated
uniformly to a starting temperature of 2050-2150°F
(1120-1180°C) and finished above 1750糉 (950°C).
Cooling should be by water quenching or as fast as possible.
Annealing is recommended after hot working to ensure
maximum corrosion resistance and optimum grain structure.
Forming or bending should not take place
in the low ductility range of 1200-1600°F (650-870°C).
This can cause intergranular tearing in austenitic alloys.
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Welding
Alloy 330 can be welded by GTAW, SMAW, and
plasma arc processes. For optimum corrosion resistance
GTAW is preferred.
Prior to welding, the material should
be in the annealed condition, clean and free from scale,
grease, and other contaminants. A zone approximately
1 inch wide on each side of the joint should be ground
to bright metal.
The interpass temperature should not exceed
300°F (150°C). Neither pre- nor post-weld heat
treatment is required. Alloy 330 can be readily welded
to a variety of dissimilar metals.
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