Alloy 330
Alloy 330 is an austenitic nickel-iron-chromium alloy with a specific addition of 1.25% silicon. It was developed specifically to handle the rigors of the industrial heat-treating environment, offering exceptional resistance to carburization and thermal shock.
- Common Forms: Plate, Sheet, Round Bar, Pipe, Mesh.
- Key Feature: Excellent Carburization & Oxidation Resistance.
- Strength: Good strength up to 2100°F (1150°C).
- Stability: Resistant to thermal cycling and quenching.
In heat treating furnaces, metals undergo brutal conditions: rapid heating, quenching, and exposure to carbon-rich atmospheres. Standard stainless steels become brittle or dissolve. Alloy 330 excels here because its **Silicon** content aids in the formation of a tightly adherent oxide scale, while its high **Nickel** content (35%) prevents embrittlement (sigma phase formation) and stress corrosion cracking.
Carburization Resistance
The alloy resists the absorption of carbon and nitrogen, preventing the material from becoming brittle during carburizing and carbonitriding cycles.
Thermal Shock Resistance
Designed to withstand rapid temperature changes, such as oil quenching, without cracking or severe distortion.
Immunity to Sigma Phase
The microstructure remains stable even after long-term exposure to intermediate temperatures, unlike Incoloy 800 or 300 series stainless.
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 34.0 - 37.0 |
| Chromium (Cr) | 17.0 - 20.0 |
| Silicon (Si) | 1.0 - 1.5 |
| Iron (Fe) | Balance |
| Manganese (Mn) | 2.0 max |
| Carbon (C) | 0.08 max |
*Note: The Silicon addition is the critical differentiator from Incoloy 800.
| Product Form | ASTM / ASME Standards |
|---|---|
| Plate, Sheet, Strip | ASTM B536, ASME SB536 |
| Bar & Rod | ASTM B511, ASME SB511 |
| Pipe (Seamless & Welded) | ASTM B535, ASTM B710, ASME SB535 |
| Pipe Fittings | ASTM B366, ASME SB366 |
| Property | Typical Values (Room Temp) |
|---|---|
| Tensile Strength | 80 - 95 ksi (550 - 655 MPa) |
| Yield Strength (0.2% Offset) | 30 - 45 ksi (205 - 310 MPa) |
| Elongation | 35 - 45 % |
| Hardness (Rockwell B) | 70 - 85 HRB |
*Note: Alloy 330 remains ductile even after long-term service.
Heat Treating Baskets
Trays, baskets, and fixtures used to hold parts during carburizing and hardening cycles.
Furnace Muffles
Retorts and muffles that must contain controlled atmospheres at high temperatures.
Radiant Tubes
Heating tubes in gas-fired furnaces that are subjected to intense thermal cycling.
Petrochemical
Pigtails and headers in pyrolysis furnaces requiring carburization resistance.
Need Alloy 330 for Furnaces?
We maintain a large stock of Alloy 330 plate, bar, and pipe. Contact us for cut-to-size material for your thermal processing equipment.
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