Jiangyin Jiangnan Metal Co., Ltd.
Nickel alloy forgings · Heat-resistant grade
UNS N08330 Forgings Alloy 330, RA330®, Incoloy® 330, W.Nr. 1.4886 / 1.4864, SUH 330. Seamless rolled rings, discs, bars, shafts and flanges forged to drawing.
UNS N08330, known in industry as Alloy 330, RA330®, Incoloy® 330, W.Nr. 1.4886 / 1.4864 and JIS SUH 330, is an austenitic nickel-iron-chromium heat-resistant alloy. It contains 34–37 % nickel, 17–20 % chromium and 0.75–1.50 % silicon, with iron as the balance. The silicon, nominally 1.25 %, is responsible for its oxidation and carburisation resistance to 1148 °C (2100 °F). The alloy stays fully austenitic at every temperature, so it does not form embrittling sigma phase, and it has no precipitation-hardening response.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The company forges UNS N08330 into seamless rolled rings, discs, shafts, sleeves, flanges and blocks weighing 20 kg to approximately 10 tonnes per piece, supplied solution annealed to ASTM B564 with EN 10204 3.1 or 3.2 certification. Enquiries: +86 189 2135 9659, sales@steelforgepieces.com.
- UNS
- N08330
- Werkstoff
- 1.4886
- Nickel
- 34–37 %
- Chromium
- 17–20 %
- Silicon
- 0.75–1.50 %
- Max service
- 1148 °C
- Density
- 7.94 g/cm³
- Forging spec
- ASTM B564
01What UNS N08330 is
UNS N08330 is a wrought austenitic nickel-iron-chromium alloy used for continuous service in hot furnace atmospheres that contain carbon. It is strengthened in solid solution and carries no precipitation-hardening additions.
Silicon is the element that separates it from the heat-resisting stainless steels. Most stainless grades cap silicon at around 1.5 % and set no minimum, whereas UNS N08330 requires at least 0.75 % and normally runs at 1.25 %. Silicon forms a tight adherent oxide scale and slows carbon pickup, so the alloy holds up in carburising and nitriding atmospheres where 310S will scale and carburise.
Three things follow from this composition:
- Fully austenitic at all temperatures. UNS N08330 does not form sigma phase, so it does not embrittle at room temperature after long exposure at heat. Types 309 and 310 stainless steel do.
- No response to hardening heat treatment. There is no solution-plus-age cycle that raises the strength of this alloy. Any increase has to come from cold work, which is seldom used on parts destined for furnace service.
- Tolerance of thermal shock. The alloy was developed for parts that are heated and liquid quenched repeatedly, which is the reason it became standard for heat-treat baskets and fixtures.
UNS N08330 is widely listed as "330 stainless steel". At 34–37 % nickel it holds roughly twice the nickel of 310S and about nine times that of 304, and ASTM covers it under the nickel-alloy specifications B511, B512 and B564 rather than the stainless steel ones. For costing, machining and welding it should be treated as a nickel alloy.
02Equivalent grades and trade names
| System / country | Designation | Notes |
|---|---|---|
| UNS (USA) | N08330 | The controlling designation. Orders should reference this. |
| Common name | Alloy 330 | Generic industry name, unrestricted. |
| AISI / SAE | 330 | Legacy designation, still in circulation. |
| Germany / EN | 1.4886, 1.4864 | X12NiCrSi35-16 and X12NiCrSi36-16. Close, though the ranges differ slightly. |
| Japan (JIS) | SUH 330 | Heat-resisting steel bar and plate. |
| Trade name | RA330® | Registered trademark of Rolled Alloys, Inc. |
| Trade name | Incoloy® 330 | Trademark of Special Metals Corporation. |
| Aerospace | AMS 5716 | Bars, forgings and rings, 35Ni-19Cr. |
Trade names remain the property of their owners and appear here only to identify the grade. Jiangyin Jiangnan Metal Co., Ltd. has no affiliation with Rolled Alloys, Inc. or Special Metals Corporation, and supplies material to the UNS N08330 chemistry and to whichever ASTM or AMS specification the order states. Werkstoff 1.4886 and 1.4864 differ slightly in their carbon and silicon ranges, so a drawing that calls out a DIN or EN number should be flagged at enquiry.
03Governing specifications by product form
| Specification | Product form covered | Relevance to forgings |
|---|---|---|
| ASTM B564 / ASME SB-564 | Nickel alloy forgings | Primary forging specification. Order UNS N08330 forgings to this. |
| ASTM B512 | Billets and bars for reforging | Covers the input stock from which N08330 forgings are made. |
| ASTM B511 / ASME SB-511 | Bars and shapes | Used for forged and rolled bar deliveries. |
| ASTM B535 / ASME SB-535 | Seamless pipe and tube | Reference for matching pipework. |
| ASTM B536 / ASME SB-536 | Plate, sheet and strip | Reference for fabricated assemblies. |
| ASTM B546 | Welded tube | Reference only. |
| ASTM B710 / ASME SB-710 | Welded pipe | Reference only. |
| ASTM B739 | Rod and bar | Reference only. |
| SAE AMS 5716 | Bars, forgings and rings | Aerospace forging specification. |
| SAE AMS 5592 | Sheet, strip and plate | Reference only. |
Jiangyin Jiangnan Metal Co., Ltd. supplies UNS N08330 forgings principally to ASTM B564, working from reforging stock to ASTM B512. Where a customer specification calls for AMS 5716 this should be stated at enquiry, since the testing and documentation scope is different.
04Chemical composition
The limits below are the ASTM ranges for UNS N08330. Nickel and silicon are the two elements that control how the alloy behaves in service. A heat that falls short on either will not perform as Alloy 330 even if every other element is within range.
All values in weight percent. Iron balance is nominally 43 %. Some specifications additionally limit copper to 1.00 % max, lead to 0.005 % max and tin to 0.025 % max, so the governing specification should be stated at enquiry if these apply. Nominal silicon is 1.25 %.
05Mechanical properties
The table separates specified minima from typical test results. Minima are what the material has to reach before a certificate can be issued. Typical values are what a properly annealed forging usually returns. Design calculations should use the minima.
| Property | Specified minimum | Typical value |
|---|---|---|
| Tensile strength | 483 MPa (70 ksi) | 550–620 MPa (80–90 ksi) |
| Yield strength, 0.2 % offset | 207 MPa (30 ksi) | 240–290 MPa (35–42 ksi) |
| Elongation in 4D | 30 % | 40–45 % |
| Reduction of area | – | 50–60 % |
| Hardness | – | 140–185 HB |
| Impact, Charpy V-notch at 20 °C | – | > 100 J |
Room-temperature tensile figures say very little about behaviour at 1000 °C. Above roughly 650 °C the allowable stress is governed by creep and stress rupture rather than by yield strength. Load-bearing parts should be sized from creep-rupture data for the actual design life and service temperature. Jiangyin Jiangnan Metal Co., Ltd. supplies the material and elevated-temperature test results; the design calculation remains with the purchaser.
06Physical and thermal properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.94 g/cm³ | 0.287 lb/in³ |
| Melting range | 1371–1425 °C | 2500–2600 °F |
| Modulus of elasticity, 20 °C | 196 GPa | 28.4 × 10⁶ psi |
| Specific heat, 20 °C | 460 J/kg·K | 0.11 Btu/lb·°F |
| Thermal conductivity, 100 °C | 12.6 W/m·K | 87 Btu·in/hr·ft²·°F |
| Electrical resistivity, 20 °C | 1.02 µΩ·m | 614 Ω·circ mil/ft |
| Mean CTE, 20–500 °C | 15.5 µm/m·°C | 8.6 × 10⁻⁶ in/in·°F |
| Mean CTE, 20–1000 °C | 17.6 µm/m·°C | 9.8 × 10⁻⁶ in/in·°F |
| Relative magnetic permeability | approx. 1.02, non-magnetic | approx. 1.02 |
| Machinability rating | 20–25 % of B1112 | 20–25 % |
Published density for this grade ranges from about 7.9 to 8.1 g/cm³ depending on source and heat. Jiangyin Jiangnan Metal Co., Ltd. uses 7.94 g/cm³ for weight calculation on quotations unless the customer specification states otherwise.
Thermal expansion
At a mean coefficient of 17.6 µm/m·°C, a 6 m UNS N08330 retort taken from 20 °C to 1000 °C grows by roughly 103 mm. Muffles, retorts and radiant tube supports have to be designed with room for that movement. A restrained part will buckle well before the alloy reaches any metallurgical limit.
07Forging and heat treatment
| Operation | Parameter | Notes |
|---|---|---|
| Soaking / charge | 1150–1180 °C | Uniform soak. Overheating coarsens the grain irrecoverably. |
| Forging start | 1150 °C | Heavy reductions early to break down the cast structure. |
| Forging finish | above 950 °C | Below this the alloy work hardens fast and cracking risk rises. Reheat rather than continue. |
| Cooling after forging | Air cool | Section-thickness dependent. |
| Solution anneal | 1038–1121 °C | Rapid air cool or water quench. This is the delivery condition. |
| Ageing / precipitation hardening | Not applicable | Solid-solution alloy with no age-hardening response. |
| Stress relief | Full anneal only | Intermediate stress-relief temperatures are not normally used. |
A number of supplier pages state that UNS N08330 is supplied "solution treated and aged". That is incorrect. UNS N08330 is a solid-solution strengthened alloy and has no precipitation-hardening response. The correct delivery condition is solution annealed at 1038–1121 °C followed by rapid cooling. Where a drawing calls for an ageing cycle on N08330, query it before ordering. The requirement has almost certainly been copied across from a precipitation-hardening grade such as Inconel 718 or Nimonic 80A.
Machining
UNS N08330 machines at roughly 20–25 % of the rate of B1112 free-machining steel and work hardens as it is cut. Use a rigid setup, sharp tooling with positive rake, low surface speed and a heavy positive feed. The tool must not be allowed to dwell or rub. Light finishing cuts tend to skid on the work-hardened layer left by the previous pass, so a deeper cut usually gives the better result.
Welding
The alloy welds by conventional processes. Preheat is not required, and post-weld heat treatment is not normally required either. Matching filler of the RA330-04 type covers most work, while ERNiCr-3 (Alloy 82) is used for dissimilar joints and high-restraint sections. AWS ER330 filler is not recommended. Keep interpass temperature low and run stringer beads rather than wide weaves.
08Forged shapes and sizes
Jiangyin Jiangnan Metal Co., Ltd. produces UNS N08330 as open-die forgings and seamless rolled rings to customer drawing. There is no stock catalogue; every part is forged to order. The sizes below are the working range of the presses and ring mill.
Seamless rolled rings
Radially rolled rings with continuous circumferential grain flow. Used for furnace rotating parts and flanged joints.
OD 200–3000 mm · wall 30–400 mm · height 20–800 mmForged discs and blanks
Upset and pierced discs for tube sheets, covers and machining blanks.
OD 100–2000 mm · thickness 20–600 mmRound bars and billets
Forged round bar for reforging or direct machining, to ASTM B511 and B512.
Ø 50–800 mm · length to 6000 mmShafts and spindles
Stepped and plain shafts for furnace rolls, fans and conveyor drives.
Ø 80–800 mm · length to 8000 mmSleeves, bushings, hollow bar
Trepanned or mandrel-forged hollows. Saves machining time on long bores.
OD 100–1500 mm · ID from 60 mmFlanges and tube sheets
Weld-neck, slip-on, blind and special flanges. Tube sheets drilled or undrilled.
DN 15–DN 2000 · to drawingBlocks and rectangles
Forged rectangular blocks for valve bodies, dies and machined weldments.
To 1500 × 800 × 600 mmSpecial and near-net shapes
Nozzles, valve seat rings, crank and eccentric shafts forged to profile.
To drawing · 20 kg–10 t per piece| Condition | Description | Typical use |
|---|---|---|
| As-forged, descaled | Forged, annealed, shot blasted | Customer performs all machining |
| Rough machined | Machined all over with agreed allowance, typically 3–8 mm | Most common. Permits full UT coverage |
| Finish machined | To final drawing tolerance | Drop-in replacement parts |
| Proof machined and bored | Bored and faced for through-wall UT | Critical rotating and pressure parts |
09UNS N08330 against 310S and Incoloy 800H
These three grades overlap between roughly 900 °C and 1100 °C and are often substituted for one another on price. They behave differently enough that any substitution should be checked against the actual service conditions.
Maximum temperature for oxidation resistance in continuous service. This is a scaling limit and not a load-bearing limit. Allowable stress at these temperatures is governed by creep.
| Criterion | UNS N08330 | 310S (S31008) | Incoloy 800H (N08810) |
|---|---|---|---|
| Nickel | 34–37 % | 19–22 % | 30–35 % |
| Chromium | 17–20 % | 24–26 % | 19–23 % |
| Silicon | 0.75–1.50 %, minimum set | 1.50 % max, no minimum | 1.00 % max |
| Max oxidation service | 1148 °C | 1093 °C | 1093 °C |
| Carburisation resistance | Excellent | Moderate | Good |
| Thermal shock and cycling | Excellent, designed for liquid quench | Poor to moderate | Good |
| Sigma-phase embrittlement | Does not form | Susceptible | Not normally |
| Creep-rupture strength | Moderate | Moderate | Highest of the three |
| ASME code pressure parts | Not normally | Limited | Yes, Sections I and VIII |
| Relative cost | High | Low | High |
| Suited to | Carburising atmospheres, repeated quenching, furnace fixtures | Clean oxidising air, cost-driven static parts | Pressurised elevated-temperature vessels and piping |
10Applications for UNS N08330 forgings
| Industry | Typical forged components | Reason for the grade |
|---|---|---|
| Heat treatment | Basket and fixture hubs, retort flanges, muffle end rings, quench-line roll shafts, radiant tube supports | Repeated heating and liquid quenching without cracking |
| Petrochemical and refining | Furnace tube hangers, burner nozzle bodies, reformer supports, hot-gas valve components | Carburisation resistance in coking and reforming service |
| Cement and lime | Kiln nose ring segments, cooler grate carriers, calciner sleeves | Abrasive hot dust combined with thermal cycling |
| Power generation | Fan hubs, hot-gas ducting flanges, ash-handling components | Scale resistance and a stable microstructure |
| Chemical processing | Rotating seal sleeves, agitator shafts, high-temperature valve bodies and seat rings | Resistance to chloride stress-corrosion cracking |
| Glass and ceramics | Kiln furniture supports, roller shafts, lehr components | Long-term dimensional stability at temperature |
| Waste incineration | Grate bar carriers, hot flue-gas dampers, tube-sheet blanks | Mixed oxidising and reducing atmospheres |
11Testing, inspection and certification
Every UNS N08330 forging produced by Jiangyin Jiangnan Metal Co., Ltd. is traceable to its heat number from melt through to despatch.
| Item | Standard or method | Scope |
|---|---|---|
| Melting route | EAF + AOD/VOD, optional ESR remelt | ESR on request for critical sections |
| Chemical analysis | Ladle and product analysis, optical emission spectrometry | Standard on every heat |
| Positive material identification | PMI by handheld XRF | Standard on every piece |
| Tensile test | ASTM A370 / ISO 6892-1 | Standard per heat and heat-treatment lot |
| Hardness | Brinell, ASTM E10 | Standard |
| Ultrasonic testing | EN 10228-3, ASTM A388 or SEP 1921 | Standard. Acceptance class to be stated at enquiry |
| Liquid penetrant | ASTM E165 / EN 10228-2 | On request |
| Grain size | ASTM E112 | On request |
| Intergranular corrosion | ASTM A262, practice as specified | On request |
| Elevated-temperature tensile | ASTM E21 | On request |
| Dimensional report | Against customer drawing | Standard |
| Certification | EN 10204 3.1 standard, 3.2 third party | 3.2 through TUV, SGS, BV, DNV or Lloyd's Register |
Third-party 3.2 certification and witnessed testing have to be agreed before production starts, as both affect routing and lead time.
12How to order UNS N08330 forgings
Send a drawing to sales@steelforgepieces.com. Where no drawing exists, the five items below are enough to produce a firm quotation, normally within one working day.
- Geometry. A 2D drawing, 3D model, or the finished outside diameter, inside diameter, height or length and wall thickness.
- Delivery condition. As-forged, rough machined with allowance, or finish machined, together with the machining allowance if there is a preference.
- Specification. ASTM B564 unless the drawing states otherwise. Note any DIN, EN or AMS callout.
- Inspection scope. Ultrasonic standard and acceptance class, plus any PMI, grain size, intergranular corrosion or elevated-temperature testing.
- Certification and quantity. EN 10204 3.1 or 3.2, the piece quantity, and whether this is a prototype or a repeat order.
13Frequently asked questions about UNS N08330
What is UNS N08330?
UNS N08330 is an austenitic nickel-iron-chromium heat-resistant alloy containing 34–37 % nickel, 17–20 % chromium and 0.75–1.50 % silicon, with iron as the balance. It is usually called Alloy 330 and is also sold as RA330® and Incoloy® 330. The silicon addition gives it oxidation and carburisation resistance to 1148 °C (2100 °F).
Is UNS N08330 a stainless steel?
No. It is often listed as 330 stainless steel, but at 34–37 % nickel it carries roughly twice the nickel of 310S and about nine times that of 304. ASTM covers UNS N08330 under the nickel-alloy specifications B511, B512 and B564, not under the stainless steel specifications.
What is the maximum service temperature of UNS N08330?
Oxidation and carburisation resistance holds to about 1148 °C (2100 °F) in continuous service, roughly 55 °C above type 310 and 110 °C above type 309. That figure is a scaling limit only. Load-bearing capacity at those temperatures is set by creep, so allowable stress has to be checked against creep-rupture data for the intended service life.
Can UNS N08330 be age hardened?
No. UNS N08330 is a solid-solution alloy with no precipitation-hardening response, so there is no solution-plus-age cycle that will raise its strength. Forgings are delivered solution annealed, normally at 1038–1121 °C followed by rapid air cooling or water quench.
Which standards cover UNS N08330 forgings?
ASTM B564 is the forging specification and includes UNS N08330. Reforging stock is covered by ASTM B512 and bars and shapes by ASTM B511. Other product forms are B535 for seamless pipe and tube, B536 for plate, sheet and strip, B546 for welded tube, B710 for welded pipe and B739 for rod and bar. On the aerospace side, AMS 5716 covers bars, forgings and rings, and AMS 5592 covers sheet, strip and plate.
What are the equivalent grades of UNS N08330?
Alloy 330, RA330® (registered to Rolled Alloys, Inc.), Incoloy® 330 (Special Metals Corporation), Werkstoff 1.4886 and 1.4864, X12NiCrSi35-16 and X12NiCrSi36-16, JIS SUH 330 and AISI 330 all refer to the same grade. A trade name on its own is not an adequate purchase description. Order against UNS N08330 plus the applicable ASTM or AMS specification.
What is the difference between UNS N08330 and 310S?
Nickel and silicon. UNS N08330 runs 34–37 % nickel with a guaranteed 0.75 % silicon minimum, while 310S runs 19–22 % nickel with silicon capped at 1.5 % and no minimum. That gives N08330 better carburisation resistance and better behaviour under thermal cycling, and it carries no risk of sigma-phase embrittlement, which 310S does. UNS N08330 costs more and is harder to machine.
What is the difference between UNS N08330 and Incoloy 800H?
Incoloy® 800H (UNS N08810) runs 30–35 % nickel and 19–23 % chromium with controlled carbon and grain size, and it is code-accepted for pressure-retaining service under ASME Sections I and VIII. UNS N08330 has more nickel and a silicon minimum, which puts it ahead in carburising and thermal-cycling service, but its creep-rupture strength is lower and it is not normally used for code pressure parts. Use 800H for pressurised elevated-temperature vessels and N08330 for furnace internals and fixtures.
What forging temperature is used for UNS N08330?
Start at about 1150 °C and finish above roughly 950 °C. Below that the alloy work hardens quickly and the risk of cracking rises, so the piece is reheated rather than forged colder. Heavy reductions early in the sequence break down the cast structure. Solution annealing follows at 1038–1121 °C with rapid cooling.
Which forged shapes are available in UNS N08330?
Jiangyin Jiangnan Metal Co., Ltd. forges UNS N08330 into seamless rolled rings, discs, round bars, shafts, sleeves, bushings, hollow bars, flanges, tube sheets, blocks, valve bodies and machining blanks. Ring outside diameters run from 200 mm to 3000 mm, and single-piece forged weight reaches about 10 tonnes.
How is UNS N08330 welded?
UNS N08330 welds by conventional processes without preheat, and post-weld heat treatment is not normally required. Matching filler of the RA330-04 type covers most work, and ERNiCr-3 (Alloy 82) is used for dissimilar joints and high-restraint sections. AWS ER330 is not recommended. Keep interpass temperature low and run stringer beads rather than wide weaves.
Is UNS N08330 magnetic?
No. UNS N08330 stays fully austenitic at all temperatures and does not transform to martensite, so relative permeability sits close to 1.0 in the annealed condition.
Who supplies UNS N08330 forgings from China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, supplying custom UNS N08330 forgings and seamless rolled rings for export. Contact +86 189 2135 9659 or sales@steelforgepieces.com. Material is supplied with EN 10204 3.1 certification as standard and 3.2 on request.
What certification is supplied with UNS N08330 forgings?
EN 10204 3.1 as standard. The certificate carries the heat number, ladle and product analysis, mechanical test results, the heat treatment record and non-destructive test results. EN 10204 3.2 witnessed by TUV, SGS, BV, DNV or Lloyd's Register is available and should be raised at enquiry stage, as it affects lead time.
14References
- ASTM B564, Standard Specification for Nickel Alloy Forgings. ASTM International. store.astm.org
- ASTM B512, Standard Specification for Nickel-Chromium-Iron-Silicon Alloy Billets and Bars for Reforging. ASTM International.
- ASTM B511, Standard Specification for Iron-Nickel-Chromium-Silicon Alloy Bars and Shapes. ASTM International.
- SAE AMS 5716, Alloy Bars, Forgings and Rings, 35Ni-19Cr. SAE International.
- Rolled Alloys, Inc., RA330® alloy data sheet and comparison with 309 and 310 stainless steels. rolledalloys.com
- AZoM, Super Alloy INCOLOY Alloy 330 (UNS N08330). azom.com
- EN 10204, Metallic products: Types of inspection documents. CEN.
- EN 10228-3, Non-destructive testing of steel forgings: Ultrasonic testing of ferritic or martensitic steel forgings. CEN.
Technical data on this page is compiled from the specifications and supplier data sheets listed above together with the production experience of Jiangyin Jiangnan Metal Co., Ltd. It is offered as guidance for material selection and is not a substitute for engineering design calculation. Property values should be confirmed against the mill certificate supplied with the specific heat. Last technical review 30 August 2026.