# AISI 330 Forgings: UNS N08330, Alloy 330, 1.4864

Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel: +86-189-2135-9659
Email: sales@steelforgepieces.com
Source page: https://www.steelforgepieces.com/Stainless-Steel/AISI-330.html

AISI 330 is an austenitic nickel-chromium-iron-silicon alloy built for furnace service rather than wet corrosion. High Temp Metals describes it as having outstanding resistance to oxidation and carburization with high strength. Sandmeyer Steel explains that the 34 to 37 percent nickel content keeps the alloy highly resistant both to chloride stress corrosion cracking and to embrittlement from sigma phase precipitation, with oxidation resistance further enhanced by the silicon addition. Jiangyin Jiangnan Metal forges it into retort and muffle sections, radiant tube components, fan hubs, grid and basket fittings, rolled rings and heavy discs for heat-treatment plant, petrochemical furnaces and power generation.

## Grade identification

| Item | Value |
|---|---|
| UNS | N08330 |
| Common names | Alloy 330, AISI 330, Incoloy alloy 330 |
| DIN / EN | 1.4864, also 1.4333 |
| SAE | 30330, SAE J405 and J412 (30330) |
| AMS | 5592, 5716 |
| Structure | Austenitic, non-magnetic when annealed, not hardenable by heat treatment |
| Forging specification | ASTM B511, bars and shapes |

Classification note: this grade is sold both as "330 stainless" and as a nickel alloy. Sandmeyer Steel calls it an austenitic nickel-iron-chromium alloy; High Temp Metals calls it an austenitic nickel-chromium-iron-silicon alloy. With 34 to 37 percent nickel, the nickel alloy description is the more accurate one. It is a valid comparison against 310S and 309, and not a substitute for 304 or 316 in aqueous service.

Trade name note: RA330 is a registered trademark of Rolled Alloys. Sandmeyer states Alloy 330 is comparable to and competes directly with RA330. We supply to UNS N08330 and the ASTM specifications, not RA330 branded material.

## Chemical composition, weight percent

| Element | Specified minimum | Specified maximum | Typical |
|---|---|---|---|
| Nickel | 34.0 | 37.0 | 36 |
| Chromium | 17.0 | 20.0 | 19 |
| Silicon | 0.75 | 1.50 | 1.13 |
| Manganese | - | 2.00 | 2 |
| Carbon | - | 0.08 | 0.080 |
| Phosphorus | - | 0.030 | 0.040 |
| Sulfur | - | 0.030 | 0.030 |
| Iron | Balance | Balance | 42 |

Sources: specified limits per the High Temp Metals type analysis and the Sandmeyer Steel specification sheet, which agree; typical values per the AZoM grade 330 datasheet.

Two commercial points. Silicon is a deliberate addition with a 0.75 percent floor, not a residual, because Sandmeyer attributes the enhanced oxidation resistance directly to it. And the AZoM typical phosphorus value of 0.040 sits above the 0.030 specified maximum, which is a reminder to buy against a standard and read the certificate rather than relying on typical tables.

## Mechanical properties at room temperature

| Property | ASTM minimum | Typical, mill annealed | Annealed reference |
|---|---|---|---|
| Tensile strength | 483 MPa, 70.0 ksi | 552 to 586 MPa, 80 to 85 ksi | 550 MPa |
| Yield strength, 0.2% offset | 207 MPa, 30.0 ksi | 207 to 296 MPa, 30 to 43 ksi | 260 MPa |
| Elongation | 30% in 4D | 40 to 45% in 2 in | 40% in 50 mm |
| Hardness | - | 70 to 85 HRB | - |
| Modulus of elasticity | - | 196 GPa, 28.5 x 10^6 psi | 197 GPa |
| Poisson's ratio | - | - | 0.27 to 0.30 |

Sources: ASTM minima for sheet and plate per High Temp Metals; typical mill annealed range per Sandmeyer Steel; annealed reference values per AZoM.

Room temperature strength is modest and largely beside the point for this alloy. It is bought for behaviour after long exposure at temperature, where creep strength and oxide scale stability decide service life.

## Physical properties

| Property | Value |
|---|---|
| Density | 8.08 g/cm3, 0.292 lb/in3 (Sandmeyer); 8 g/cm3 (AZoM); 0.287 lb/in3 for RA330 (Rolled Alloys) |
| Melting range | 1343 to 1393 C, 2450 to 2540 F (Rolled Alloys, RA330) |
| Specific heat | 460 J/kg.C at 0 to 100 C, 0.11 BTU/lb.F at 32 to 212 F |
| Coefficient of thermal expansion | 14.4 um/m.C, 8 uin/in.F (AZoM) |
| Magnetic permeability | 1.02 at 20 C; mu = 1.009 annealed at H = 2810 oersted for RA330 |
| Electrical resistivity | 1.017 uOhm.m at 24 C, rising to 1.245 uOhm.m at 982 C |

### Thermal conductivity against temperature

| F | 75 | 400 | 800 | 1200 | 1600 | 1800 |
|---|---|---|---|---|---|---|
| C | 24 | 204 | 427 | 649 | 871 | 982 |
| W/m.C | 12.4 | 15.6 | 19.3 | 23.4 | 28.6 | 31.2 |

Source: Sandmeyer Steel specification sheet. The published table lists 227 C against 800 F, evidently a typographic slip for 427 C.

Conductivity rises roughly two and a half times between room temperature and 982 C while the expansion coefficient stays comparatively low. High Temp Metals highlights that combination of low thermal expansion with good oxidation resistance, and it is much of why the alloy survives thermal cycling that distorts cheaper furnace materials.

## Temperature capability

Published maxima range from 1095 to 1200 C depending on source and criterion.

| Source | Stated limit | Criterion |
|---|---|---|
| Sandmeyer Steel | about 1095 C, 2000 F | Resists scale formation up to this temperature |
| Sandmeyer Steel, FAQ | 1149 C, 2100 F | Oxidation resistance |
| Rolled Alloys, RA330 | 1148 C, 2100 F | Good strength, carburization and oxidation resistance |
| High Temp Metals | 1204 C, 2200 F | Resistance to oxidation and carburization, with high strength |
| AZoM | 1200 C, 2200 F | High strength and resistance to carburization and oxidation |

Design to the lower figures where tight scaling control or mechanical load is involved, and treat the 2200 F figures as a short-excursion or lightly loaded ceiling.

### Carburization, nitridation and green rot

Sandmeyer attributes the carburization resistance to the roughly 35 percent nickel content together with the silicon addition, and states that in alternating carburizing and oxidizing atmospheres the alloy shows excellent resistance to the green rot phenomenon. Nitridation resistance is good where oxygen content is low, which is why the alloy is used extensively in components handling cracked ammonia. The high nickel also suppresses sigma phase embrittlement, allowing parts to be thermally cycled over long periods.

## Forging and heat treatment

1. Heat uniformly to 1120 to 1180 C (2050 to 2150 F) as the starting temperature.
2. Finish above 950 C (1750 F). AZoM narrows the hot working window to 1149 to 1177 C.
3. Do not form or bend between 650 and 870 C (1200 to 1600 F). Both Sandmeyer and High Temp Metals identify this as the low ductility range where austenitic alloys suffer intergranular tearing.
4. Cool by water quench or as fast as possible after hot working.
5. Anneal after hot working for maximum corrosion resistance and optimum grain structure. Full anneal 1020 to 1120 C (1870 to 2050 F), water quenched for optimum creep resistance, or rapid air cooling to below 425 C (800 F). AZoM quotes a wider band of 1121 to 1204 C.

No hardening route exists. The alloy is austenitic and cannot be hardened by thermal treatment; only cold working raises room temperature strength, and High Temp Metals notes cold working is difficult because of the alloy's strength and work hardening rate. A hardness band on an N08330 drawing is usually an error worth querying before manufacture.

### Welding and machining

Sandmeyer states the alloy can be welded by GTAW, SMAW and plasma arc, with GTAW preferred for optimum corrosion resistance. Practical conditions: material in the annealed condition, clean and free of scale and grease; a zone about one inch either side of the joint ground to bright metal; interpass temperature not exceeding 150 C (300 F); neither pre-weld nor post-weld heat treatment required. It welds readily to a range of dissimilar metals. For machining, High Temp Metals recommends rigid mounts, sulfurized lubricants, positive feeds and slow speeds.

## Standards

| Specification | Scope |
|---|---|
| ASTM B511 | Nickel-iron-chromium-silicon alloy bars and shapes; the specification normally applied to forged bar and forged shapes |
| ASTM B536, ASME SB-536 | Plate, sheet and strip; named with AMS 5592 on the Sandmeyer specification sheet |
| ASTM B535 | Seamless pipe and tube |
| ASTM B546 | Welded tube |
| ASTM B512 | Nickel-iron-chromium-silicon alloy castings |
| ASTM B366 | Factory-made wrought fittings |
| ASTM B739 | Bar rounds, listed by Carpenter Technology for grade 330 |
| AMS 5592, AMS 5716 | Aerospace material specifications |

Standard documentation is a chemical analysis and mechanical test report to EN 10204 3.1. Ultrasonic testing, PMI, dye penetrant, grain size determination, hot tensile testing at service temperature and third-party witness inspection are available on request and should be specified at enquiry stage.

## Applications

Sandmeyer groups the uses as follows. Chemical and petrochemical processing: cracked ammonia components, petrochemical furnace parts, 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 and components, high temperature fans, salt pots. High Temp Metals adds furnace parts, heat-treat components and containers and boiler fixtures. AZoM lists gas turbines, heat exchangers, general heat treating equipment and neutral and cyanide salt pots.

In forged form the most common enquiries are retort and muffle flanges and end sections, radiant tube return bends and hubs, fan hubs and shafts for high temperature circulation fans, rolled rings for furnace door frames and seal faces, heavy discs and tubesheets for hot gas heat exchangers, salt pot bodies and fittings, and replacement grid, basket and fixture components where fabricated 310S assemblies have distorted or carburized.

## Forged products supplied

| Category | Items |
|---|---|
| Bars | Round bars, rods, square bars, rectangular and flat bars, hexagonal bars, forged shafts and step shafts |
| Hollow and tubular | Hollow bars, sleeves, bushings, forged pipe and tube sections, retort and muffle bodies, casings, shells, cylinders, hubs, housings |
| Rings | Forged rings, seamless rolled rings, door and seal frames, ring flanges, retaining rings |
| Flat and solid | Discs, blocks, forged plates, tubesheets, cover plates |
| Fabrication inputs | Forged blanks and near-net shapes, rough-machined and finish-machined components, parts with weld preparation |

No fixed size catalogue. Send the drawing or a dimensioned sketch with the quantity, the governing specification, the service temperature and the furnace atmosphere. The last two matter on this grade, because atmosphere decides whether N08330 is the right alloy at all.

## Frequently asked questions

**What is AISI 330 alloy?**
An austenitic nickel-chromium-iron-silicon alloy, UNS N08330, with 34 to 37 percent nickel and 17 to 20 percent chromium. Outstanding resistance to oxidation and carburization with high strength, plus resistance to chloride stress corrosion cracking and sigma phase embrittlement. Non-magnetic when annealed, not hardenable by heat treatment.

**Is it a stainless steel or a nickel alloy?**
Sold both ways. The datasheets treat it as a nickel-iron-chromium alloy, which with 34 to 37 percent nickel is the more accurate description.

**How hot can it run?**
Between 1095 and 1200 C depending on source and criterion. Design to the lower end where scaling control or mechanical load matters.

**At what temperature is it forged?**
Start at 1120 to 1180 C, finish above 950 C, cool as fast as possible, anneal afterwards. Never form or bend between 650 and 870 C.

**Can it be hardened?**
No. Only cold working raises room temperature strength, and cold working is difficult because of the work hardening rate.

**How does it compare with 310S?**
310S relies mainly on its 25 percent chromium; N08330 relies on 34 to 37 percent nickel plus a deliberate silicon addition, which the sources credit for its carburization resistance and its resistance to green rot in alternating atmospheres. Where carburizing or cracked ammonia atmospheres and thermal cycling are the problem, N08330 is the stronger candidate. For straightforward high temperature oxidation, 310S is often cheaper.

**Can you supply one piece?**
Yes. Open-die forging suits single prototypes and replacement parts as readily as batches. Send the drawing for feasibility, forged weight and lead time, usually within one working day.

## Related grades

AISI 444, PH13-8Mo, 15-5PH, 17-7PH, Incoloy 800H, Incoloy 800HT, Incoloy 825, Inconel 601, Inconel 617, Inconel 690, all supplied as open-die forgings.

## Contact

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel +86-189-2135-9659
Email sales@steelforgepieces.com
Enquiries answered within 24 hours, Monday to Saturday, China Standard Time (UTC+8).

Sources: Sandmeyer Steel Company, Alloy 330 (UNS N08330) specification sheet overview and plate FAQ; High Temp Metals, Alloy 330 technical data; AZoM, Stainless Steel Grade 330 (UNS N08330) datasheet; Rolled Alloys, RA330 data sheet and product page; Carpenter Technology grade 330 listing; MakeItFrom UNS N08330 specification list. RA330 is a registered trademark of Rolled Alloys.

Compiled by the technical sales department, Jiangyin Jiangnan Metal Co., Ltd. Figures are for guidance and are drawn from third-party datasheets. The values governing an order are those on the EN 10204 3.1 certificate issued with the goods.