Alloy 617 ForgingsUNS N06617 · W.Nr. 2.4663a · NiCr23Co12Mo
Alloy 617 is a solid-solution strengthened nickel-chromium-cobalt-molybdenum superalloy used in continuous service up to approximately 1100 °C (2010 °F). Jiangyin Jiangnan Metal Co., Ltd. supplies it as open-die forgings and seamless rolled rings to ASTM B564, including forged rings, flanges, discs, shafts, sleeves, bushings, tube sheets and round bars produced to customer drawing.
- UNS number
- N06617
- Werkstoff
- 2.4663a
- Alloy family
- Ni-Cr-Co-MoSolid-solution strengthened
- Density
- 8.36 g/cm³0.302 lb/in³
- Melting range
- 1332–1380 °C2430–2516 °F
- Tensile, min
- 485 MPa70,300 psi, annealed
- Yield 0.2%, min
- 275 MPa39,900 psi, annealed
- Elongation, min
- 25 %Hardness approx. 170 HB
- Melting route
- EAF + VOD + ESR
- Certification
- EN 10204 3.13.2 on request
What is Alloy 617?
Alloy 617 (UNS N06617) is a nickel-base superalloy strengthened by solid solution rather than by precipitation. The nominal composition is 22% chromium, 12.5% cobalt, 9% molybdenum and 1.2% aluminium, with nickel as the balance. Chromium and aluminium form a protective oxide scale that resists oxidation to about 1100 °C. Cobalt and molybdenum provide solid-solution strengthening and raise creep-rupture strength at temperature.
The alloy is not gamma-prime hardened, so it does not lose strength through overageing during long exposure at high temperature. This makes it suitable for components that remain hot for tens of thousands of hours in service. Alloy 617 also resists carburising and nitriding atmospheres better than iron-base heat-resisting grades, and performs well in the reducing gas streams found in petrochemical furnaces.
Above about 900 °C, Alloy 617 provides higher creep-rupture strength than Incoloy 800H and higher oxidation resistance than Inconel 600. Where aqueous corrosion resistance is the main requirement rather than high-temperature strength, Inconel 625 and Hastelloy C-276 are more commonly specified.
Equivalent designations and trade names
| System | Designation |
|---|---|
| UNS | N06617 |
| Werkstoff / EN | 2.4663a · 2.4663 |
| DIN | NiCr23Co12Mo |
| Trade names | Inconel 617 · Nicrofer 5520 Co · Haynes 617 · VDM Alloy 617 |
| GB (China) | NS3105 · GH3617 |
Inconel is a registered trademark of Special Metals Corporation, Nicrofer of VDM Metals and Haynes of Haynes International. These names are listed here only to identify equivalent chemistry. Material is supplied to UNS N06617 and the governing ASTM or ASME specification.
Chemical composition of Alloy 617
The composition limits below are those of ASTM B564 and ASME SB-564 for UNS N06617 forgings. Each heat is verified by spectrometric analysis and the result is reported on the EN 10204 3.1 certificate.
| Element | Symbol | Weight % |
|---|---|---|
| Nickel | Ni | 44.5 min (balance) |
| Chromium | Cr | 20.0 – 24.0 |
| Cobalt | Co | 10.0 – 15.0 |
| Molybdenum | Mo | 8.0 – 10.0 |
| Aluminium | Al | 0.80 – 1.50 |
| Carbon | C | 0.05 – 0.15 |
| Iron | Fe | 3.0 max |
| Manganese | Mn | 1.0 max |
| Silicon | Si | 1.0 max |
| Titanium | Ti | 0.6 max |
| Copper | Cu | 0.5 max |
| Sulphur | S | 0.015 max |
| Boron | B | 0.006 max |
Aluminium content affects the stability of the protective alumina scale at the upper end of the temperature range. Heats close to the 0.80% minimum and heats close to the 1.50% maximum behave differently under long-term oxidising exposure. A narrowed aluminium range can be specified on the purchase order where the application requires it.
Mechanical and physical properties
The values below are for the solution-annealed condition at room temperature unless stated otherwise. Acceptance minimums are governed by the ordering specification and the customer drawing. The figures shown here are intended for preliminary design reference.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | ≥ 485 MPa | ≥ 70,300 psi |
| Yield strength (0.2% offset) | ≥ 275 MPa | ≥ 39,900 psi |
| Elongation in 4D | ≥ 25 % | |
| Hardness | approx. 170 HB | |
| Modulus of elasticity | 211 GPa | 30.6 × 10⁶ psi |
| Property | Value |
|---|---|
| Density | 8.36 g/cm³ (0.302 lb/in³) |
| Melting range | 1332 – 1380 °C (2430 – 2516 °F) |
| Max continuous service temp. | approx. 1100 °C (2010 °F), oxidising |
| Thermal conductivity, 20 °C | 13.4 W/m·K |
| Mean thermal expansion, 20–100 °C | 11.6 µm/m·K |
| Specific heat, 20 °C | 419 J/kg·K |
| Electrical resistivity, 20 °C | 1.22 µΩ·m |
| Magnetic response | Non-magnetic |
Elevated-temperature tensile and stress-rupture testing can be added to the order and reported on the certificate. Please state the required test temperature at enquiry stage, as additional testing affects delivery time.
Alloy 617 forged product forms
All items listed below are produced by open-die forging or ring rolling to customer drawing. Near-net-shape forging reduces machining loss on this material, so please supply the finished dimensions and a suitable forging envelope will be proposed.
- Also supplied: forged round bars, square and rectangular blocks, hollow bars, forged pipes and tubes, nozzles, valve bodies, valve seat rings and stems, gear blanks, forged rolls, crankshafts and eccentric shafts.
- Delivery condition: as-forged, rough machined, solution annealed or finish machined to drawing. Please state the required condition on the enquiry.
- Surface condition: descaled, pickled, shot blasted or machined all over.
| Form | Outside diameter / length | Unit weight |
|---|---|---|
| Seamless rolled rings | OD 200 – 3000 mm | up to 5000 kg |
| Forged discs | OD 100 – 2000 mm | up to 4000 kg |
| Round bars | Ø 50 – 800 mm | per length |
| Shafts | length up to 6000 mm | up to 3000 kg |
| Sleeves / bushings | OD 100 – 1500 mm | up to 2500 kg |
| Tube sheets | OD up to 2500 mm | up to 5000 kg |
Sizes outside these ranges are quoted case by case. Please send the drawing so that feasibility can be confirmed before quotation.
Manufacturing route for Alloy 617 forgings
Alloy 617 has a narrow hot-working temperature range and work-hardens quickly, so process control during forging is more critical than for carbon and alloy steel. The production route below is followed on a typical order.
1. Melting and ingot supply
Material is melted by EAF and VOD, then remelted by ESR. Electroslag remelting reduces sulphur and non-metallic inclusion content, which is required in order to meet tight ultrasonic acceptance classes. ESR material is recommended for rotating components and pressure-retaining parts.
2. Open-die forging and ring rolling
Forging begins at approximately 1180 °C and finishes above 980 °C. Below 980 °C the alloy loses ductility and becomes liable to crack, so the workpiece is returned to the furnace rather than worked further. Reduction is planned to break down the cast structure through the full section. Rings are rolled to give continuous circumferential grain flow instead of being cut from plate.
3. Heat treatment
The standard delivery condition is solution annealed at 1150 – 1175 °C followed by rapid cooling or water quench. This dissolves carbides formed during hot working and restores ductility. Where the customer specification requires it, an ageing treatment between 760 °C and 980 °C is applied afterwards to control grain-boundary carbide precipitation. Furnace charts are supplied with the certificate.
4. Machining and inspection
Rough machining and finish machining are carried out in-house to the customer drawing. Dimensional inspection, hardness and surface condition are recorded before release.
5. Non-destructive testing and certification
- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, at the acceptance class stated on the order.
- Liquid penetrant testing to ASTM E165 where surface indications are critical.
- EN 10204 3.1 mill certificate as standard, covering chemistry, mechanical results, heat treatment record and NDT report.
- EN 10204 3.2 certification witnessed by TÜV, BV, SGS, LRS or DNV on request. Please nominate the inspection body at order stage so that witness points can be scheduled.
Applications for Alloy 617 forgings
Alloy 617 is specified for components that must carry load in hot oxidising or carburising atmospheres over extended periods. The main application areas are listed below.
Gas turbines
Combustor cans and liners, transition ducts, exhaust components and casing rings, where creep-rupture life above 900 °C determines the inspection interval.
Ultra-supercritical power
Superheater and reheater headers, tube sheets, valve bodies and piping components for USC and A-USC steam plant operating above 700 °C.
Petrochemical and refining
Furnace hardware, reformer and cracking furnace internals, nozzles and flanges exposed to carburising gas streams that attack iron-base grades.
Heat treatment plant
Retorts, muffles, fans, baskets, grids and fixtures subject to repeated cycling between ambient temperature and 1100 °C.
Chemical process
Nitric acid catalyst grids and support rings, calciner and reactor internals, columns, towers and pressure vessel forgings.
Aerospace and nuclear
Exhaust and afterburner components, and high-temperature gas-cooled reactor structures where long-term thermal stability is required.
Alloy 617 frequently asked questions
Is Alloy 617 the same as Inconel 617?
Yes. Inconel 617 is the Special Metals trade name for the chemistry designated UNS N06617. Nicrofer 5520 Co and Haynes 617 are the VDM and Haynes names for the same alloy. A forging ordered as Alloy 617 to ASTM B564 meets the same chemical and mechanical requirements as one ordered under any of those brand names.
What is the maximum service temperature of Alloy 617?
Approximately 1100 °C (2010 °F) in continuous oxidising service, with useful creep-rupture strength retained above 980 °C. For pressure-retaining parts the allowable stress is taken from the applicable ASME Boiler and Pressure Vessel Code case rather than from the oxidation limit, and the code figure is normally the lower of the two.
Which specifications cover Alloy 617 forgings?
ASTM B564 and ASME SB-564 cover forgings and forged fittings. Related product forms are covered by ASTM B166 for rod, bar and wire, ASTM B168 for plate, sheet and strip, ASTM B167 for seamless pipe and tube, AMS 5887 for bar and forgings, and AMS 5888 for sheet, plate and strip. German practice uses DIN 17742/17744 and VdTÜV 485.
How does Alloy 617 compare with Incoloy 800H and Inconel 625?
Above approximately 900 °C, Alloy 617 has considerably higher creep-rupture strength than Incoloy 800H and better resistance to carburising atmospheres. Inconel 625 has higher strength at moderate temperatures and better aqueous corrosion resistance, but is subject to long-term phase instability above about 650 °C. Alloy 617 is normally specified for sustained high-temperature service and Inconel 625 for wet corrosive service.
What heat treatment do the forgings receive?
Solution annealing at 1150 – 1175 °C followed by rapid cooling or water quench, which dissolves carbides formed during hot working. An ageing treatment between 760 °C and 980 °C is applied afterwards where the customer specification requires controlled grain-boundary carbide precipitation. Both operations are performed in-house and the furnace chart is issued with the certificate.
Is Alloy 617 difficult to machine?
Alloy 617 work-hardens rapidly. Recommended practice follows normal nickel superalloy machining: rigid setup, positive rake carbide tooling, constant heavy feed, reduced surface speed and adequate coolant. The tool should not be allowed to dwell in the cut, since this work-hardens the surface and shortens tool life. Rough machined and finish machined parts can be supplied where required.
What testing and certification is included?
Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 at the specified acceptance class, together with chemical analysis, tensile testing, hardness and grain size, all reported on an EN 10204 3.1 mill certificate. EN 10204 3.2 certification witnessed by TÜV, BV, SGS, LRS or DNV is available. Please nominate the inspection body at order stage.
Who manufactures Alloy 617 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing Alloy 617 (UNS N06617) forgings and seamless rolled rings to ASTM B564. Enquiries: +86-189-2135-9659 or sales@steelforgepieces.com.
How do I request a quotation?
Send the drawing or the finished dimensions, the quantity, the governing specification and any NDT or third-party inspection requirement to sales@steelforgepieces.com. A quotation covering forging weight, delivery condition, testing scope and lead time is normally returned within 24 hours on working days. Where the grade has not yet been selected, please advise the application and service temperature and a recommendation will be provided.
Send your Alloy 617 drawing
Please provide the finished dimensions, quantity, governing specification and any NDT or third-party inspection requirement. Feasibility will be confirmed and the quotation will cover forging weight, delivery condition and lead time.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Telephone / WhatsApp / WeChat
- +86-189-2135-9659
- Works address
- No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China