UNS N06455 Forgings: Hastelloy® C-4 Rolled Rings, Bars, Flanges and Shafts
Jiangyin Jiangnan Metal Co., Ltd. forges UNS N06455 (Alloy C-4, W.-Nr. 2.4610) to customer drawings. Seamless rolled rings, round bars, flanges, discs, shafts, sleeves and tube sheets, supplied solution annealed to ASTM B564 with EN 10204 3.1 or 3.2 certification.
- Alloy type
- Ni-Cr-Mo
- Nominal Cr / Mo
- 16 % / 16 %
- Tungsten
- None
- Density
- 8.64 g/cm³
- Solution anneal
- 1066 °C + WQ
- Forging standard
- ASTM B564
- Ring OD
- ≤ 3000 mm
- Certification
- EN 10204 3.1
Quick answer
UNS N06455 is a low-carbon nickel-chromium-molybdenum alloy with about 16 % chromium and 16 % molybdenum, balance nickel. It contains no tungsten, so it does not sensitize in the weld heat-affected zone and keeps its ductility after long exposure between 650 °C and 1040 °C. Most welded equipment in this grade can be put into service without a post-weld anneal. The same material is sold as Hastelloy® C-4 and Alloy C-4.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. We forge UNS N06455 rings, bars, flanges, shafts and discs to drawing, solution annealed at 1066 °C and water quenched, with ultrasonic testing to ASTM A388 and EN 10204 3.1 or 3.2 certification. Email sales@steelforgepieces.com or call 0086-189-2135-9659.
What is UNS N06455 alloy?
UNS N06455 is the UNS number for the wrought nickel-chromium-molybdenum alloy sold as Hastelloy® C-4. The same material appears in specifications as Alloy C-4, W.-Nr. 2.4610 and NiMo16Cr16Ti under DIN 17744 and DIN 17752. It belongs to the C-family of corrosion-resistant alloys, together with C-276, C-22 and C-2000.
The difference from those grades is the absence of tungsten. Iron is also capped at 3 %, carbon at 0.015 % and silicon at 0.08 %, and titanium up to 0.70 % is added to tie up residual carbon. With that chemistry the alloy does not form the grain-boundary carbides and mu-phase that embrittle tungsten-bearing Ni-Cr-Mo alloys when they are held in the 650 to 1040 °C range.
For a fabricator this removes a process step. Welded vessels, reactor internals and piping in UNS N06455 can normally go into service without a post-weld solution anneal, which on a large fabrication saves a furnace cycle and the handling risk that comes with it.
Chromium and molybdenum are present in roughly equal amounts, so the alloy works in both oxidizing and reducing acids. It also resists pitting, crevice attack and chloride stress corrosion cracking in halide-bearing media where austenitic stainless steels fail.
Note on grade selection. UNS N06455 and UNS N10276 (C-276) are often listed by traders as interchangeable. They are not. C-276 carries 3 to 4.5 % tungsten and around 5 % iron and is the stronger of the two; C-4 is the more thermally stable. We ask customers to confirm which grade the design calls for, since the two behave differently after thermal exposure.
UNS N06455 chemical composition
| Element | ASTM min % | ASTM max % | Our control % | Function in the alloy |
|---|---|---|---|---|
| NiNickel | Bal. | Bal. | Bal. (approx. 65) | Matrix; general corrosion resistance and ductility |
| CrChromium | 14.0 | 18.0 | 14.5–17.5 | Protective Cr2O3 film; resistance to oxidizing acids |
| MoMolybdenum | 14.0 | 17.0 | 14.0–17.0 | Resistance to reducing acids, pitting and crevice attack |
| FeIron | — | 3.00 | ≤ 3.00 | Residual, held low for phase stability |
| CoCobalt | — | 2.00 | ≤ 2.00 | Residual |
| MnManganese | — | 1.00 | ≤ 1.00 | Deoxidiser |
| TiTitanium | — | 0.70 | ≤ 0.70 | Stabilises carbon; suppresses carbide precipitation in the HAZ |
| SiSilicon | — | 0.08 | ≤ 0.05 | Held low to prevent intermetallic precipitation |
| CCarbon | — | 0.015 | ≤ 0.009 | Held low to prevent sensitization when welded |
| PPhosphorus | — | 0.040 | ≤ 0.025 | Residual; limits grain-boundary embrittlement |
| SSulphur | — | 0.030 | ≤ 0.010 | Residual; controlled for hot ductility |
The fourth column is the tighter range we order forging stock to. Holding carbon, silicon, phosphorus and sulphur below the ASTM ceiling improves weldability and lowers the risk of intergranular attack in service. Where a purchase order cites a customer or national specification, we melt and certify to that specification instead.
UNS N06455 mechanical and physical properties
| Property | ASTM minimum | Typical as forged | Test method |
|---|---|---|---|
| Tensile strength, Rm | 690 MPa · 100 ksi | 760–800 MPa | ASTM E8 / ISO 6892-1 |
| Yield strength, Rp0.2 | 275 MPa · 40 ksi | 310–380 MPa | ASTM E8 / ISO 6892-1 |
| Elongation, A5 | 40 % | 50–60 % | ASTM E8 |
| Reduction of area | Not specified | 55–70 % | ASTM E8 |
| Hardness | ≤ 100 HRB | 85–92 HRB | ASTM E18 |
| Impact energy, Charpy V, RT | Not specified | > 200 J | ASTM E23 |
Minimum values are the ASTM acceptance criteria for solution-annealed material. Typical values are for design screening only and are not a guarantee of supply. Section size, forging reduction and quench rate all affect the result. Acceptance values are agreed at order stage and reported per heat on the certificate.
| Property | Metric | Imperial | Test method or note |
|---|---|---|---|
| Density | 8.64 g/cm³ | 0.312 lb/in³ | ASTM B311 |
| Melting range | 1350–1400 °C | 2460–2550 °F | Liquidus to solidus |
| Modulus of elasticity, RT | 211 GPa | 30.6 × 10³ ksi | ASTM E111 |
| Thermal expansion, 20–100 °C | 10.8 µm/m·K | 6.0 µin/in·°F | ASTM E228 |
| Thermal conductivity, RT | 10.1 W/m·K | 70 Btu·in/h·ft²·°F | ASTM E1225 |
| Electrical resistivity | 1.25 µΩ·m | 753 Ω·cmil/ft | ASTM B193 |
| Magnetic permeability | 1.0002 | 1.0002 | Essentially non-magnetic |
| Max. continuous service temperature | 1040 °C | 1900 °F | Oxidising atmosphere |
UNS N06455 against C-276, C-22 and Alloy 59
| Criterion | Alloy C-4 | Alloy C-276 | Alloy C-22 | Alloy 59 |
|---|---|---|---|---|
| UNS number | N06455 | N10276 | N06022 | N06059 |
| Material number | 2.4610 | 2.4819 | 2.4602 | 2.4605 |
| Nominal Cr | 16 % | 16 % | 22 % | 23 % |
| Nominal Mo | 16 % | 16 % | 13 % | 16 % |
| Tungsten | None | 3.8 % | 3.0 % | None |
| Nominal Fe | ≤ 3 % | 5.5 % | ≤ 3 % | ≤ 1.5 % |
| Thermal stability | Highest of the four | Mu-phase risk on ageing | Good | Very good |
| Strength | Moderate | Highest | High | High |
| Best suited to | Welded assemblies exposed to 650–1040 °C; nitric and mixed acids | Longest service record; hot reducing acids; highest loads | Oxidising and mixed-acid duty | Highest pitting resistance |
If the weld heat-affected zone will spend a long time between 650 °C and 1040 °C, UNS N06455 is the safer choice. It will not sensitize and normally needs no post-weld anneal. If the part is highly loaded, or the duty is dominated by hot reducing acids, C-276 is usually specified instead. We forge all four grades and can quote them side by side on the same drawing. See Hastelloy C-276 forgings
UNS N06455 forged products and size range
| Product form | Size range | Typical condition |
|---|---|---|
| Seamless rolled rings | OD 200–3000 mm · H 50–1000 mm | Rough-machined or as-forged |
| Forged round bars | Ø 50–800 mm · L ≤ 6000 mm | +5/−0 mm as-forged; h9 machined |
| Forged flanges | OD ≤ 2500 mm | ASME B16.5 / B16.47 or to drawing |
| Forged discs and blanks | Ø 200–2000 mm | Rough-machined |
| Forged shafts and spindles | Ø 100–700 mm · L ≤ 8000 mm | Machining allowance to drawing |
| Forged sleeves and bushings | OD ≤ 1500 mm | Bored and rough-turned |
| Hollow bars and forged tubes | OD ≤ 1000 mm | Trepanned or bored |
| Forged tube sheets | Ø ≤ 2000 mm | Flat, rough-machined, drilled on request |
| Valve bodies, stems and seat rings | To drawing | Near-net forged |
| Forged blocks and rectangles | Thickness ≤ 600 mm | Six faces machined on request |
Single-piece forging mass 5 kg to 8000 kg. Sizes outside this envelope are quoted case by case.
How UNS N06455 forgings are manufactured
1. Melting
Stock is melted by electric arc furnace with argon-oxygen or vacuum oxygen decarburisation (EAF + AOD/VOD) and remelted by electroslag remelting. Where the specification calls for cleaner material we use vacuum induction melting followed by ESR or VAR. The alloy depends on holding carbon and silicon at the bottom of the range, so the melting route is agreed at enquiry stage and recorded on the certificate with the heat number.
2. Open-die forging and ring rolling
UNS N06455 has a narrow hot-working window and is more sensitive to strain rate than austenitic stainless steel. Forging starts at 1177 °C (2150 °F) and finishes no lower than 954 °C (1750 °F), using moderate reductions and frequent re-heating rather than heavy single passes. A forging reduction ratio of at least 4:1 in the critical direction breaks down the as-cast structure. Ring blanks are pierced and expanded on a radial-axial ring rolling mill, which gives continuous circumferential grain flow.
3. Solution annealing
Forgings are solution annealed at 1066 °C (1950 °F), held 10 to 30 minutes according to section thickness, then water quenched. This dissolves carbides formed during hot working and restores the microstructure the alloy depends on for corrosion resistance. UNS N06455 is not age-hardened. It is a solid-solution alloy, so an ageing treatment adds nothing to corrosion resistance and only reduces ductility. A supplier offering N06455 in a solution treated and aged condition for corrosion service should be questioned.
4. Machining
Parts are supplied as-forged, rough-machined with an agreed allowance, or finish-machined to drawing. The alloy work-hardens, so tool life is best with positive-rake carbide tooling, low cutting speed, heavy feed, rigid setups and plenty of coolant. We keep carbon-steel tools and brushes away from the work to avoid iron contamination of the finished surface.
Testing, inspection and certification
- Chemical analysis. ICP-OES or spectrographic analysis on each heat, reported element by element. Positive material identification on the finished part on request.
- Mechanical testing. Tensile to ASTM E8 or ISO 6892-1 and hardness to ASTM E18. Charpy impact and elevated-temperature testing on request.
- Ultrasonic testing. To ASTM A388, EN 10228-3 or SEP 1921, at the acceptance class stated on the order.
- Liquid penetrant testing. To ASTM E165 or ASME Section V for surface indications where specified.
- Intergranular corrosion testing. ASTM G28 Method A, boiling ferric sulphate and sulphuric acid, to confirm the solution anneal was effective.
- Grain size and microstructure. ASTM E112, with photomicrographs on request.
- Sour service. NACE MR0175 and ISO 15156 compliance statements where the application calls for them.
- Material certification. EN 10204 type 3.1 as standard. Type 3.2 with third-party witness by SGS, BV, TÜV or Lloyd's Register on request.
Applications for UNS N06455 forgings
Chemical processing
Reactor shell rings, flanges, tube sheets and agitator shafts in hot contaminated mineral acids. Equipment normally goes into service as-welded.
Pharmaceutical and fine chemicals
Reactor internals, valve bodies and nozzles, where a stable low-carbon microstructure keeps contamination risk down.
Pulp and paper bleaching
Rolled rings, discs and pump sleeves exposed to chlorine dioxide and hot chloride liquors.
Flue gas desulphurisation
Flanges, shafts and wear rings in contact with acid chloride condensate in scrubbers and absorbers.
Oil, gas and subsea
Wellhead components, valve stems and bushings chosen for chloride stress corrosion cracking resistance and NACE compliance.
Nuclear and waste treatment
Fuel reprocessing and waste-handling forgings in nitric acid service, where stability after thermal exposure decides the material.
Heat exchangers and pressure vessels
Forged tube sheets, shell rings and blind flanges supplied as ASME SB-564 or SB-462 code material.
Pumps, valves and rotating equipment
Plunger pump shafts, seat rings, valve blocks and compressor hardware for acid and halide duty.
Frequently asked questions about UNS N06455
What is UNS N06455 alloy used for?
It goes into equipment that has to resist hot acids and chlorides and stay stable after welding or long thermal exposure. Common parts are reactor shell rings, flanges and tube sheets in chemical and pharmaceutical plant, pump shafts and sleeves in bleaching and scrubbing duty, valve bodies and stems for acid service, and forgings for nuclear fuel reprocessing equipment.
Is UNS N06455 the same as Hastelloy C-4?
Yes. UNS N06455 is the UNS number for the alloy sold under the Hastelloy® C-4 trademark, also known as Alloy C-4, W.-Nr. 2.4610 and NiMo16Cr16Ti. Hastelloy is a registered trademark of Haynes International, Inc. The name appears on this page only to identify the equivalent grade. Jiangyin Jiangnan Metal Co., Ltd. is not a licensee of that trademark.
What is the chemical composition of UNS N06455?
Chromium 14.0 to 18.0 % and molybdenum 14.0 to 17.0 %, with nickel as the balance at roughly 65 %. Iron is capped at 3.0 %, cobalt at 2.0 %, manganese at 1.0 % and titanium at 0.70 %. Carbon is limited to 0.015 % and silicon to 0.08 %. There is no tungsten, which is the main difference from C-276 and C-22. Full ranges are in Table 1 above.
Which ASTM standards cover UNS N06455 forgings?
ASTM B564 covers nickel alloy forgings and ASTM B462 covers forged or rolled flanges and fittings. Bar and wire follow ASTM B574, plate and sheet ASTM B575, seamless pipe and tube ASTM B622, welded pipe ASTM B619 and fittings ASTM B366. For pressure vessel work under ASME Section II Part B, the equivalent specifications are SB-564, SB-462, SB-574 and SB-575.
What heat treatment is applied to UNS N06455 forgings?
Solution annealing at about 1066 °C (1950 °F), held 10 to 30 minutes depending on section thickness, then water quenched. UNS N06455 is a solid-solution alloy and is not age-hardened for corrosion service. Ageing adds nothing to corrosion resistance and reduces ductility. Jiangyin Jiangnan Metal Co., Ltd. supplies all N06455 forgings solution annealed unless the order says otherwise.
What is the difference between UNS N06455 (C-4) and UNS N10276 (C-276)?
C-276 contains roughly 3 to 4.5 % tungsten and about 5 % iron. C-4 contains no tungsten and caps iron at 3 %. Without tungsten, C-4 resists mu-phase and grain-boundary precipitation during long exposure between about 650 and 1040 °C, so welded assemblies stay tough and can usually be used as-welded. C-276 is stronger and has a longer service record in hot reducing acids.
Can UNS N06455 be welded and machined?
It welds readily by GTAW, GMAW and SMAW with a matching filler. Since the heat-affected zone does not sensitize, it is normally used as-welded with no post-weld solution anneal. Surfaces must be clean of oil, grease, sulphur and iron before welding. For machining, the alloy work-hardens quickly: positive-rake carbide tooling, low surface speed, heavy feed, rigid fixturing and plenty of coolant, and do not let the tool dwell in the cut.
Which UNS N06455 forged shapes can Jiangyin Jiangnan Metal supply?
Seamless rolled rings from 200 to 3000 mm OD, forged round bars from Ø 50 to 800 mm, flanges, discs and blanks, shafts, sleeves and bushings, hollow bars and forged tubes, tube sheets, valve bodies and forged blocks. Single-piece mass runs from 5 kg to 8000 kg. Everything is forged to customer drawing or to a dimensional standard named on the order.
What certification is supplied with UNS N06455 forgings?
Every order ships with an EN 10204 type 3.1 material certificate giving heat number, chemical analysis, mechanical test results, heat-treatment record and NDT results. Type 3.2 certification witnessed by SGS, BV, TÜV or Lloyd's Register is available on request. Ultrasonic testing is carried out to ASTM A388, EN 10228-3 or SEP 1921, and ASTM G28-A intergranular corrosion testing can be added to verify the solution anneal.
Who supplies UNS N06455 forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China that makes UNS N06455 (Hastelloy® C-4) nickel alloy forgings: rolled rings, bars, flanges, shafts, discs and tube sheets, forged to customer drawing, with EN 10204 3.1 or 3.2 certification and export supply worldwide. The factory is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Enquiries to sales@steelforgepieces.com or 0086-189-2135-9659.
What is the minimum order quantity and lead time for UNS N06455?
There is no fixed minimum. Single prototype pieces are accepted, and single-piece orders are common for plant spares. Lead time runs 25 to 45 days for forgings made from stock material, and 45 to 70 days where a dedicated heat has to be melted, counted from drawing approval. Confirmed dates go out with the order acknowledgement.
How much do UNS N06455 forgings cost?
The alloy is priced per kilogram and follows the nickel and molybdenum markets, so quotations are issued against a current-day metal price and normally hold for 15 to 30 days. Price depends on finished weight, input weight after machining allowance, melting route, testing scope and certification level. Send a drawing, or the dimensions and quantity, to sales@steelforgepieces.com for a firm quotation.
Request a quotation for UNS N06455 forgings
Send a drawing, or just the outside diameter, wall or thickness, length and quantity. Jiangyin Jiangnan Metal Co., Ltd. answers UNS N06455 enquiries within one working day with price, forged weight, lead time and the testing and certification scope we propose.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory - Factory address
- No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China - Telephone / WhatsApp / WeChat
- 0086-189-2135-9659
Related nickel and cobalt alloy forgings
- Hastelloy C-276
- Hastelloy C-22
- Hastelloy C-2000
- Hastelloy B-2
- Hastelloy B-3
- Hastelloy X
- Hastelloy G-3
- Alloy 59
- Inconel 625
- Inconel 718
- Inconel 690
- Incoloy 825
- Incoloy 926
- Monel 400
- UMCO 51
References
ASTM B564 / ASME SB-564, Standard Specification for Nickel Alloy Forgings. ASTM B462 / ASME SB-462, Forged or Rolled Alloy Pipe Flanges, Forged Fittings, and Valves and Parts for Corrosive High-Temperature Service. ASTM B574, Low-Carbon Nickel-Chromium-Molybdenum Alloy Rod. ASTM B575, Low-Carbon Nickel-Chromium-Molybdenum Alloy Plate, Sheet and Strip. EN 10204, Metallic products, types of inspection documents. EN 10228-3, Non-destructive testing of steel forgings, ultrasonic testing. ASTM G28, Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys.
Hastelloy® is a registered trademark of Haynes International, Inc. Inconel®, Incoloy® and Monel® are registered trademarks of their respective owners. These names are used only to identify equivalent grades. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with, endorsed by, or a licensee of these trademark holders.
Maintained by the technical sales team at Jiangyin Jiangnan Metal Co., Ltd. Last reviewed .