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 1750¼F (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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