A240 Type 330 | UNS N08330 | Alloy 330 Stainless Steel Plate
What is A240 Type 330/ UNS N08330/ Alloy 330 Stainless Steel？
As a professional China steel mill-Direct Supply and stainless steel plate supplier, SHH STEEL is pleased to present A240 Type 330 | UNS N08330 | Alloy 330 Stainless Steel Plate.
Alloy 330 is widely known and searched under many different names and designations, including Alloy 330, AISI 330, ASTM A240 Type 330, ASME SA240 Type 330, UNS N08330, RA330, Incoloy 330, 1.4886, 1.4864, X12NiCrSi35-16, X10NiCrSi35-19, SUH330, 1Cr16Ni35, Nicrofer 3718 and NA17. All these names generally refer to the same high-nickel heat-resisting austenitic alloy family used for elevated-temperature service.
Alloy 330 is a nickel-iron-chromium-silicon austenitic alloy containing approximately 34–37% nickel and 17–20% chromium, with controlled silicon. The high nickel content provides excellent resistance to carburization, chloride stress corrosion cracking and sigma-phase embrittlement. Chromium and silicon work together to form a stable protective scale, giving outstanding oxidation resistance at high temperature. Typical continuous service is in the range of about 980–1150°C, depending on atmosphere and thermal cycling.
The grade is non-magnetic in the annealed condition, cannot be hardened by heat treatment, and is widely used for furnace parts, heat-treatment fixtures, radiant tubes, muffles, retorts, petrochemical heaters and other equipment exposed to oxidizing or carburizing atmospheres.
SHH STEEL supplies Alloy 330 as true China steel mill-Direct Supply, sourcing directly from major Chinese stainless steel and heat-resisting alloy mills. This model delivers competitive mill pricing, consistent quality, complete heat traceability and reliable delivery. SHH STEEL offers Alloy 330 in plate and sheet form across a practical range of thicknesses and surface finishes.
Alloy 330 is frequently compared with a240 309s, a240 310s, a240 310h, a240 321, a240 347 and a240 800h when selecting heat-resisting materials. SHH STEEL provides technical support to help customers choose the most appropriate grade.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | A240 Type 330 / UNS N08330 / Alloy 330 | Confirmed |
| Related Standards | ASTM A240, ASME SA240, ASTM B536, AMS 5592 | Available |
| Product Form | Plate, Sheet | Available |
| Delivery Condition | Solution Annealed | Standard |
| Thickness Range | 1 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm | Available |
| Length | Up to 6000–12000 mm or cut-to-length | Available |
| Surface Finish | No.1, 2B, and others on request | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
SHH STEEL can supply Alloy 330 dual-certified to ASTM A240 / ASME SA240 Type 330 and related nickel-alloy plate specifications when required by the project.
Chemical Composition
Typical Chemical Composition of Alloy 330 (UNS N08330 / A240 Type 330):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | 0.75 – 1.50 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.030 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.00 – 20.00 |
| Nickel (Ni) | 34.00 – 37.00 |
| Copper (Cu) | ≤ 1.00 |
| Iron (Fe) | Balance |
The combination of high nickel (34–37%), chromium (17–20%) and silicon (0.75–1.50%) is the defining chemistry of Alloy 330. Nickel improves carburization resistance, thermal-shock resistance and resistance to sigma-phase embrittlement. Chromium and silicon enhance oxidation and scaling resistance. SHH STEEL carefully controls composition to ensure consistent high-temperature performance.
Mechanical Properties
Annealed Condition (typical values)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 550 MPa (80 ksi typical) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi typical) |
| Elongation (in 50 mm) | ≥ 30–40% |
| Hardness | ≤ 217 HB / 70–85 HRB typical |
Alloy 330 retains useful strength at elevated temperature and offers good ductility in the annealed condition. It is not hardenable by heat treatment and only work-hardens by cold working. SHH STEEL supplies material with consistent high-temperature mechanical properties suitable for furnace and heat-treatment equipment.
Physical Properties
Density is approximately 8.08 g/cm³. The grade is non-magnetic in the annealed condition. Melting range is approximately 1400–1425°C. Typical continuous oxidation resistance is up to about 1150°C in air, depending on cycle conditions.
Material Comparison
| Grade | Ni (%) | Cr (%) | Key Strength | Oxidation / Carburization | Typical Preference |
|---|---|---|---|---|---|
| AISI 309S | 12–15 | 22–24 | Welded high-temp oxidation | Very Good | High-temperature oxidizing service |
| AISI 310S | 19–22 | 24–26 | Severe oxidation | Excellent | Severe high-temperature oxidation |
| AISI 321 | 9–12 | 17–19 | Ti-stabilized welded service | Good | Stabilized moderate high-temp service |
| Alloy 330 | 34–37 | 17–20 | Carburization + thermal shock | Excellent + carburization | Furnace / heat-treat / carburizing |
| Alloy 800H | 30–35 | 19–23 | Creep strength | Excellent | High-temp strength under load |
| AISI 314 | 19–22 | 23–26 | High silicon oxidation | Excellent oxidation | Severe oxidizing / mild carburizing |
Alloy 330 is selected when both high-temperature oxidation resistance and carburization resistance are required. Compared with a240 309s and a240 310s, the much higher nickel content gives better resistance to carburizing atmospheres and thermal cycling. For maximum oxidation resistance in clean air, a240 310s or a240 310h may still be preferred. For higher creep strength in long-term loaded service, SHH STEEL also supplies a240 800h.
Corrosion Resistance
Alloy 330 is primarily a heat-resisting grade rather than a wet-corrosion grade. It offers outstanding resistance to oxidation and scaling in air and oxidizing furnace atmospheres, and excellent resistance to carburization. The high nickel content also provides good resistance to chloride stress corrosion cracking and helps avoid sigma-phase embrittlement during prolonged high-temperature exposure.
At room temperature it has moderate resistance to atmospheric and mild chemical corrosion, similar to other austenitic grades, but it is not intended to replace molybdenum-bearing grades such as a240 316l or a240 904l in aggressive aqueous chloride service. For severe high-temperature oxidizing service without carburization, SHH STEEL recommends comparing with a240 310s.
Weldability
Alloy 330 has good weldability using standard fusion welding methods. Matching Alloy 330 or appropriate high-nickel heat-resisting filler metals are recommended to maintain high-temperature performance in the weld metal.
The austenitic structure and high nickel content reduce the risk of hot cracking when heat input is properly controlled. Post-weld annealing is generally not required for most furnace and heat-treatment applications. SHH STEEL recommends proper welding procedures and post-weld cleaning to achieve optimum high-temperature performance.
Heat Treatment
Alloy 330 is normally supplied in the solution-annealed condition by SHH STEEL.
Recommended solution annealing temperature range is typically 1038–1177°C, followed by rapid cooling. The alloy cannot be hardened by heat treatment. Proper annealing restores ductility after cold working and optimizes high-temperature oxidation and carburization resistance. SHH STEEL controls heat treatment to ensure consistent quality for elevated-temperature service.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, annealed and pickled | Alloy 330 No.1 – most common for industrial high-temp plate |
| 2B | Cold-rolled, annealed, pickled, skin-passed | Alloy 330 2B / A240 Type 330 2B – thinner plates |
| Special | Ground or custom finishes | Alloy 330 Special – on request |
SHH STEEL regularly supplies A240 Type 330 / Alloy 330 in No.1 finish, which is the preferred condition for most furnace and heat-treatment plate applications.
Tolerances
Dimensional tolerances for A240 Type 330 / UNS N08330 / Alloy 330 Stainless Steel Plate supplied by SHH STEEL generally conform to ASTM A480 / applicable nickel-alloy plate practices.
Typical available size range is thickness 1 mm – 50 mm, width up to 1500–2000 mm, and length up to 6000–12000 mm or cut-to-length. SHH STEEL provides precise dimensional control and can support tighter tolerances when required.
Equivalent Material Grades
| Grade / Designation | Standard / Region | Notes |
|---|---|---|
| A240 Type 330 | ASTM A240 / ASME SA240 | Plate specification |
| Alloy 330 / AISI 330 | Commercial / AISI | Common trade names |
| UNS N08330 | Unified Numbering System | Primary UNS designation |
| RA330 | Commercial | Widely used brand name |
| 1.4886 / 1.4864 | EN (Europe) | Closest European grades |
| X12NiCrSi35-16 | EN | European designation |
| SUH330 | JIS (Japan) | Japanese heat-resisting equivalent |
| 1Cr16Ni35 | GB/T (China) | Chinese related grade |
| NA17 | BS | British related designation |
Related grades for comparison include a240 309s, a240 310s, a240 310h, a240 321, a240 347 and a240 800h.
Applications
A240 Type 330 / UNS N08330 / Alloy 330 is selected for high-temperature equipment that must resist oxidation, carburization and thermal cycling. Typical applications of Alloy 330 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Heat Treatment & Furnaces | Alloy 330 furnace components, fixtures, trays, baskets |
| Industrial Heating | Alloy 330 radiant tubes, muffles, retorts and supports |
| Petrochemical & Refining | Alloy 330 heater parts and high-temperature process equipment |
| Power Generation | Alloy 330 high-temperature ducting and structural parts |
| Ore Processing & Thermal Plants | Alloy 330 equipment exposed to oxidizing/carburizing gases |
| Chemical Processing | Alloy 330 high-temperature vessels and components |
| General High-Temperature Service | A240 Type 330 plate for thermal cycling and carburizing atmospheres |
SHH STEEL supplies Alloy 330 for these elevated-temperature applications with consistent quality. For related industry solutions, see our energy industry, petrochemical industry and equipment manufacturing pages. Supporting services include steel cutting services and steel welding services.
Why Choose SHH STEEL
SHH STEEL is a China steel mill-Direct Supply specializing in stainless steel and heat-resisting alloy plate and sheet. By working directly with major Chinese mills, SHH STEEL supplies A240 Type 330 / UNS N08330 / Alloy 330 with the following advantages:
- Genuine China steel mill-Direct Supply pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- High-nickel heat-resisting material optimized for oxidation, carburization and thermal-shock service
- Flexible dimensions and surface finishes (including Alloy 330 No.1 and Alloy 330 2B)
- Technical support for selection among 309S, 310S, 310H, Alloy 330 and 800H
- Value-added services including steel cutting services, steel welding services and worldwide shipping service
For more information about our company and full product range, please visit China steel Mill Agent-SHH STEEL.
Conclusion
A240 Type 330 / UNS N08330 / Alloy 330 Stainless Steel Plate is a high-nickel austenitic heat-resisting grade designed for excellent oxidation, carburization and thermal-shock resistance. It is an outstanding choice for furnace components, heat-treatment fixtures, radiant tubes, muffles, retorts and petrochemical high-temperature equipment.
As a professional China steel mill-Direct Supply, SHH STEEL provides high-quality Alloy 330 Stainless Steel Plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including Alloy 330 No.1 and Alloy 330 2B), or a competitive quotation.
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