Nickel superalloy, open-die forgings
NiCr20Co13Mo4Ti3Al forgings W.Nr. 2.4654 · UNS N07001 · Waspaloy · GH4738. Forged rings, discs, shafts, flanges and bars
Jiangyin Jiangnan Metal Co., Ltd. forges NiCr20Co13Mo4Ti3Al to customer drawings at its open-die works in Jiangyin, Jiangsu, China. This datasheet lists the composition limits, physical and mechanical data, heat-treatment routes and forging parameters for the grade, together with the forged product range available.
- EN / DIN designation
- NiCr20Co13Mo4Ti3Al
- Werkstoff no.
- 2.4654
- UNS
- N07001
- Trade name
- Waspaloy
- China (GB / GJB)
- GH4738 (GH738)
- France (AFNOR)
- NC20K14
- Alloy system
- Ni-Cr-Co-Mo, gamma prime
- Nominal nickel
- approx. 57 %
- Density
- 8.19 g/cm³
- Melting range
- 1330 to 1360 °C
- Service temp. rotating
- to 650 °C
- Service temp. static
- to 870 °C
- Forging range
- 980 to 1170 °C
- Aged hardness
- 34 to 44 HRC
- Forged forms
- rings, discs, shafts, flanges, bars, sleeves
- Certification
- EN 10204 3.1 / 3.2
NiCr20Co13Mo4Ti3Al is the European designation for the age-hardenable nickel-chromium-cobalt-molybdenum superalloy known as Waspaloy (W.Nr. 2.4654, UNS N07001, GH4738 in China). It retains strength in rotating components to approximately 650 °C and resists oxidation to approximately 870 °C. Typical forged parts are gas turbine discs, shafts, seal rings and high-temperature fasteners. Open-die forgings in this grade are produced to drawing by Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China.
Alloy description
NiCr20Co13Mo4Ti3Al is a wrought nickel-base superalloy strengthened by two mechanisms. Chromium, cobalt and molybdenum provide solid-solution strengthening of the nickel matrix. Aluminium and titanium form a coherent gamma prime precipitate, Ni3(Al,Ti), during ageing. Boron and zirconium are present in small quantities and segregate to the grain boundaries, where they extend creep life.
Room-temperature tensile strength after full heat treatment is approximately 1200 MPa. The alloy retains substantial rupture strength after 1000 hours at 760 °C, and this property governs most applications for the grade.
Fabrication is more demanding than for Inconel 718. The hot-working range is narrow, machining rates are low, and welding is restricted to controlled procedures. These conditions are described in sections 07 and 08.
Designations, equivalents and governing standards
The alloy is specified under several designations. All entries in the table refer to the same material, and Jiangyin Jiangnan Metal quotes against any of them.
| System | Designation | Notes |
|---|---|---|
| EN / DIN | NiCr20Co13Mo4Ti3Al | Also written NiCr19Co14Mo4Ti3Al or NiCr19Co14MoTi |
| Werkstoff | 2.4654 | German material number |
| UNS | N07001 | US unified numbering system |
| Trade name | Waspaloy | Originating US trade designation |
| China | GH4738 / GH738 | Chinese superalloy designation |
| France | NC20K14 | AFNOR |
| ASTM / ASME | B637 / SB-637, grade 685 | Precipitation-hardening bar, forgings, forging stock |
| SAE AMS | 5704, 5706, 5707, 5708, 5709 | Bar, forgings, rings for aerospace |
| SAE AMS | 5544, 5828 | Sheet, plate and strip; welding wire |
| ISO | 9723, 9724, 9725 | Rod, wire, forging stock |
AMS 5704 covers forgings supplied solution, stabilisation and precipitation heat treated. AMS 5706 and AMS 5707 cover forgings, bars and rings in related conditions. The AMS number should be stated on the enquiry, since it fixes the melt route and the heat-treatment sequence in addition to the chemistry.
Chemical composition
The table gives the limiting composition for UNS N07001. Aerospace orders are normally placed against a tighter mill chemistry within these bands.
| Element | Min % | Max % | Nominal % | Function |
|---|---|---|---|---|
| Nickel (Ni) | bal. | bal. | approx. 57 | Matrix |
| Chromium (Cr) | 18.00 | 21.00 | 19.5 | Oxidation resistance, solid solution |
| Cobalt (Co) | 12.00 | 15.00 | 13.5 | Raises gamma prime solvus, solid solution |
| Molybdenum (Mo) | 3.50 | 5.00 | 4.3 | Solid solution, M6C carbides |
| Titanium (Ti) | 2.75 | 3.25 | 3.0 | Gamma prime former |
| Aluminium (Al) | 1.20 | 1.60 | 1.4 | Gamma prime former |
| Carbon (C) | 0.02 | 0.10 | 0.07 | Grain-boundary carbides |
| Boron (B) | 0.003 | 0.010 | 0.006 | Grain-boundary creep life |
| Zirconium (Zr) | 0.02 | 0.12 | 0.05 | Grain-boundary strengthening |
| Iron (Fe) | — | 2.00 | — | Residual |
| Manganese (Mn) | — | 1.00 | — | Residual |
| Silicon (Si) | — | 0.75 | — | Residual |
| Copper (Cu) | — | 0.50 | — | Residual |
| Phosphorus (P) | — | 0.030 | — | Impurity |
| Sulfur (S) | — | 0.030 | — | Impurity |
Aerospace specifications restrict the residual elements further than UNS N07001. Several European mill grades limit silicon to 0.15 % max, manganese to 0.10 % max, and phosphorus and sulfur to 0.015 % max, with ppm limits on lead, bismuth, selenium and silver. Customer specifications should be supplied with the enquiry so that the melt source can be selected accordingly.
Physical properties
| Property | Condition or temperature | Value (SI) | Value (imperial) |
|---|---|---|---|
| Density | 20 °C | 8.19 g/cm³ | 0.296 lb/in³ |
| Melting range | — | 1330 to 1360 °C | 2425 to 2475 °F |
| Elastic modulus | 21 °C | 211 GPa | 30.3 × 10³ ksi |
| Elastic modulus | 538 °C | 184 GPa | 26.7 × 10³ ksi |
| Elastic modulus | 871 °C | 157 GPa | 22.7 × 10³ ksi |
| Thermal expansion | 21 to 93 °C | 12.2 µm/m·K | 6.8 µin/in·°F |
| Thermal expansion | 21 to 538 °C | 13.9 µm/m·K | 7.7 µin/in·°F |
| Thermal expansion | 21 to 1093 °C | 18.7 µm/m·K | 10.4 µin/in·°F |
| Electrical resistivity | Solution treated | 1.24 µΩ·m | — |
| Electrical resistivity | Fully aged | 1.20 µΩ·m | — |
| Magnetic permeability | H = 200 Oe, solution treated and aged | 1.004 | — |
Mechanical properties
Room temperature, fully heat treated
| Property | Minimum (SI) | Minimum (imperial) |
|---|---|---|
| Tensile strength, Rm | 1207 MPa | 175 ksi |
| Yield strength, Rp0.2 | 827 MPa | 120 ksi |
| Elongation, 4D | 15 % | 15 % |
| Reduction of area | 18 % | 18 % |
| Hardness | 34 to 44 HRC | 34 to 44 HRC |
The values are acceptance minimums. Production forgings normally test above them. In the solution-treated condition, before stabilisation and ageing, the alloy is considerably softer, which allows bulk machining to be completed before the final properties are developed.
Stress-rupture strength, 1000-hour life
Rupture strength remains substantial at 760 °C. Gamma double prime strengthened alloys such as Inconel 718 lose their precipitate below this temperature.
Heat treatment
Heat treatment consists of three stages: solution, stabilisation and precipitation ageing. The solution temperature determines whether the part is optimised for creep resistance or for tensile strength.
| Stage | Route A, creep and stress rupture | Route B, room and elevated temperature tensile |
|---|---|---|
| Solution | 1080 °C / 4 h / air cool | 995 to 1035 °C / 4 h / oil quench |
| Hardness after solution | 20 to 25 HRC | — |
| Stabilisation | 845 °C / 24 h / air cool | 845 °C / 4 h / air cool |
| Ageing | 760 °C / 16 h / air cool | 760 °C / 16 h / air cool |
| Final hardness | 34 to 40 HRC | 34 to 44 HRC |
| Applied to | Turbine discs, shafts, long-life rotating parts | Fasteners, rings, parts sized on tensile strength |
Processing notes
- The higher solution temperature of route A coarsens the grain and increases creep life. The lower solution temperature of route B retains a finer grain and increases tensile strength. A single part cannot be optimised for both.
- Bulk machining is carried out in the solution-treated condition. Ageing is the final thermal operation before finish grinding.
- Scale formed in oxidising furnace atmospheres is removed by pickling or by mechanical means before inspection.
- Furnace charts are recorded for each cycle and issued with the EN 10204 3.1 certificate.
Forging and hot working
The hot-working range is 980 to 1170 °C. Below approximately 980 °C the alloy work-hardens rapidly and may crack. Above approximately 1180 °C it becomes hot short. The working band is therefore less than 200 °C wide, and heavy sections require frequent reheating and short transfer times.
- Reheating. Multiple reheats are normal on large sections. Pass schedules are set by furnace availability rather than by press capacity.
- Reduction. Final reduction is controlled to achieve the grain size required by the specification. Grain size affects both ultrasonic response and creep life.
- Cold work. Cold forming is possible in the annealed condition by hydroforming, drawing, spinning, bending and roll forming. Intermediate annealing is required because the alloy work-hardens rapidly.
- Ultrasonic inspectability. A coarse or duplex grain structure will not meet ultrasonic acceptance to EN 10228-3. Grain structure is controlled during forging.
Machining and welding
Machining
NiCr20Co13Mo4Ti3Al is among the more difficult superalloys to machine in any condition. The solution-treated, air-cooled condition is the most suitable state for the majority of operations. Rigid setups, sharp positive-rake carbide or ceramic tooling, low surface speed with positive feed, and flood coolant are required. The tool must not dwell in the cut, since the machined surface work-hardens immediately. On rough-machined discs, machining time frequently exceeds forging time.
Welding
The alloy is not considered readily weldable outside controlled procedures. Where welding is required, gas-shielded arc processes with matched-composition filler to AMS 5828 are used. Material is welded in the solution-treated condition and re-solution treated before service. Welds should not be located in areas of high stress, since weld strength after heat treatment does not reach that of the wrought parent material. The alloy is sensitive to strain-age cracking.
Forged products and size range
The following part families are produced in NiCr20Co13Mo4Ti3Al to customer drawing, as single items or as repeat production lots.
| Product form | Size range | Delivery condition |
|---|---|---|
| Forged rings and seamless rolled rings | OD 200 to 2000 mm, height to 600 mm | Heat treated, rough machined |
| Discs, blanks and disc forgings | OD to 1200 mm, thickness to 400 mm | Heat treated, prepared for UT |
| Shafts, spindles, stepped shafts | Ø 60 to 600 mm, length to 6000 mm | Rough turned |
| Round bars and forging stock | Ø 40 to 500 mm | Peeled or turned |
| Flanges and hubs | OD to 1500 mm | Heat treated |
| Sleeves, bushings, cylinders | OD to 1000 mm, wall from 25 mm | Bored and faced |
| Tube sheets, plates, blocks | To drawing | Heat treated |
| Single-piece weight | 10 to 3000 kg | — |
Sizes outside these ranges are quoted individually. On superalloy forgings the limiting factors are normally heat-treatment furnace capacity and the required forging reduction ratio.
Production route
- Melting. Vacuum-melted stock is used for aerospace-grade work, by VIM plus VAR or VIM plus ESR. For industrial applications, EAF plus VOD plus ESR remelted material is available at lower cost. The melt route is fixed at order stage, since it appears on the certificate.
- Billet preparation. Ingot conditioning, cropping and ultrasonic pre-check of the input stock.
- Open-die forging. Upsetting and drawing within the 980 to 1170 °C range, with reheats scheduled to hold the full section within the band. Ring blanks are punched and rolled.
- Heat treatment. Route A or route B according to the drawing, with recorded furnace charts.
- Rough machining. Turning and boring in the solution-treated condition, which produces surfaces suitable for ultrasonic testing and reveals defects at an early stage.
- Non-destructive testing. Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 as specified. Liquid penetrant on machined surfaces where required.
- Mechanical testing. Tensile and hardness testing, and stress-rupture testing where specified, from integral or prolongation test material.
- Certification and dispatch. EN 10204 3.1, or 3.2 with third-party witness. Marking, preservation and seaworthy packing.
Inspection, testing and certification
- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, at the acceptance class stated on the order.
- Liquid penetrant examination on finish-machined surfaces where the specification requires it.
- Chemical analysis. Product analysis taken from the forging, in addition to the melt analysis.
- Mechanical testing. Tensile testing at room temperature and, on request, at elevated temperature. Hardness survey. Stress-rupture testing on prolongations.
- Grain size and microstructure to ASTM E112 where specified.
- Certificates. EN 10204 3.1 as standard. EN 10204 3.2 with an independent inspection body such as TUV, SGS, BV or Lloyd's when required by the customer.
Heat number, forging record, furnace chart and NDT report are compiled into a single data book and issued with the shipment.
Applications
The alloy was developed for gas turbine engines, which remain its principal market. Forged components include the following.
- Aero and industrial gas turbines. Compressor and turbine discs, rotor spacers, shafts, seal rings, casings and casing rings.
- High-temperature fasteners. Bolts, studs and nuts for hot-section joints requiring 650 °C class strength.
- Power generation. Hot-section rotating hardware and static rings in gas turbine plant.
- Aerospace structure and propulsion. Engine hardware, airframe fittings and missile-system components.
- Process and energy equipment. High-temperature tooling, extrusion and hot-forming dies, and valve and wellhead internals where oxidation and hot-corrosion resistance are required.
Oxidation performance is satisfactory under frequent thermal cycling and in continuous exposure to approximately 1038 °C. The alloy has performed well in gas turbine combustion atmospheres and in salt spray. Solution-treated material offers the highest corrosion resistance.
Comparison with other forgeable nickel superalloys
| Alloy | Strengthening phase | Density | Temperature ceiling | Weldability | Relative cost |
|---|---|---|---|---|---|
| NiCr20Co13Mo4Ti3Al (2.4654) | Gamma prime, Ni3(Al,Ti) | 8.19 g/cm³ | 650 °C rotating, 870 °C static | Restricted | High |
| Inconel 718 (2.4668) | Gamma double prime, Ni3Nb | 8.19 g/cm³ | Approx. 650 °C | Good | Moderate |
| Rene 41 (2.4973) | Gamma prime, higher Al and Ti | 8.25 g/cm³ | Above 2.4654, to approx. 870 °C | Difficult, strain-age cracking | High |
| Nimonic 105 (2.4634) | Gamma prime, Co and Mo rich | Approx. 8.0 g/cm³ | Approx. 950 °C static | Difficult | High |
Below approximately 650 °C, Inconel 718 is normally the lower-cost option and is easier to forge and to weld. Above 650 °C the gamma double prime precipitate in 718 coarsens and dissolves, while the gamma prime in NiCr20Co13Mo4Ti3Al remains stable. Where the service temperature is higher again and welding is not required, Rene 41 and Nimonic 105 are used.
All four grades are forged at this works. Where the grade has not been fixed, the duty cycle (temperature, stress and required life) should be supplied with the enquiry.
Frequently asked questions
What is NiCr20Co13Mo4Ti3Al?
NiCr20Co13Mo4Ti3Al is an age-hardenable nickel-chromium-cobalt-molybdenum superalloy, material number 2.4654, UNS N07001, known by the trade name Waspaloy. It is strengthened by a gamma prime Ni3(Al,Ti) precipitate and is used for forged rotating parts that must retain strength at approximately 650 °C and resist oxidation to approximately 870 °C.
Is NiCr20Co13Mo4Ti3Al the same as Waspaloy?
Yes. NiCr20Co13Mo4Ti3Al is the European EN and DIN designation for the alloy sold under the Waspaloy trade name. The same material carries the numbers 2.4654 and UNS N07001, and is designated GH4738 in China and NC20K14 in France. Jiangyin Jiangnan Metal Co., Ltd. quotes and certifies against whichever designation the specification uses.
What is the Chinese equivalent of NiCr20Co13Mo4Ti3Al?
The Chinese equivalent of NiCr20Co13Mo4Ti3Al, 2.4654 and UNS N07001 is GH4738, also written GH738. Chinese-melted GH4738 is widely available and is normally the most economical route for industrial, non-aerospace forgings in this grade.
What is the maximum service temperature of NiCr20Co13Mo4Ti3Al?
Approximately 650 °C (1200 °F) for critical rotating applications such as turbine discs and shafts, and up to approximately 870 °C (1600 °F) for less demanding static applications. Oxidation resistance remains acceptable in continuous exposure to approximately 1038 °C, but mechanical strength rather than oxidation is normally the limiting factor.
What is the chemical composition of NiCr20Co13Mo4Ti3Al?
Nominally 57 % Ni, 19.5 % Cr, 13.5 % Co, 4.3 % Mo, 3.0 % Ti and 1.4 % Al, with 0.02 to 0.10 % C, 0.003 to 0.010 % B and 0.02 to 0.12 % Zr. Iron is limited to 2.00 % max, so the alloy remains fully nickel-base. Full limiting ranges are given in the composition table.
How is NiCr20Co13Mo4Ti3Al heat treated after forging?
In three stages: solution, stabilisation and precipitation ageing. For creep and stress-rupture life, solution at 1080 °C for 4 h and air cool, stabilise at 845 °C for 24 h and air cool, then age at 760 °C for 16 h and air cool, giving 34 to 40 HRC. For maximum tensile strength, solution at 995 to 1035 °C for 4 h and oil quench, stabilise at 845 °C for 4 h and air cool, then age at 760 °C for 16 h, giving 34 to 44 HRC.
At what temperature is NiCr20Co13Mo4Ti3Al forged?
Between approximately 980 °C and 1170 °C. Working below 980 °C risks cracking because the alloy work-hardens rapidly, and above approximately 1180 °C the alloy becomes hot short. The narrow working band is the reason NiCr20Co13Mo4Ti3Al forgings require frequent reheats and short transfer times.
Can NiCr20Co13Mo4Ti3Al be welded?
Only under controlled procedures. The alloy is not considered freely weldable. Gas-shielded arc welding with matched-composition filler to AMS 5828 is used, the material is welded in the solution-treated condition and re-solution treated before service, and welds are kept away from areas of high stress. The alloy is sensitive to strain-age cracking.
Is NiCr20Co13Mo4Ti3Al difficult to machine?
Yes. It is among the more difficult superalloys to machine. The solution-treated, air-cooled condition is the most suitable state for most operations. Rigid setups, positive-rake carbide tooling, low cutting speed with positive feed, and flood coolant are required, and the tool must not dwell in the cut because the machined surface work-hardens immediately.
Should NiCr20Co13Mo4Ti3Al or Inconel 718 be specified?
Below approximately 650 °C, Inconel 718 is normally cheaper, easier to forge and easier to weld. Above 650 °C the gamma double prime strengthening phase in 718 becomes unstable, while the gamma prime in NiCr20Co13Mo4Ti3Al remains stable, so 2.4654 is specified for sustained duty above that temperature. See the comparison table.
What forged shapes and sizes are available in NiCr20Co13Mo4Ti3Al?
Jiangyin Jiangnan Metal Co., Ltd. supplies forged rings and seamless rolled rings, discs and blanks, shafts and spindles, round bars, flanges and hubs, sleeves, bushings, tube sheets and blocks in NiCr20Co13Mo4Ti3Al, made to drawing as single items or repeat production lots. Size envelopes are listed in the product range table.
What certification is issued with NiCr20Co13Mo4Ti3Al forgings?
EN 10204 3.1 as standard, and EN 10204 3.2 with third-party witness on request. Ultrasonic testing is performed to EN 10228-3, SEP 1921 or ASTM A388 as specified. Heat number, furnace charts, chemical analysis, mechanical test results and NDT reports are issued together as a single data book.
How is a price obtained for a NiCr20Co13Mo4Ti3Al forging?
Send a drawing or the finished dimensions to sales@steelforgepieces.com, or call +86 189 2135 9659. The enquiry should state the specification (AMS, ASTM or customer specification), quantity, delivery condition, heat-treatment route, NDT class and certificate type. The enquiry checklist lists the full requirement.
Requesting a quotation
The following information is required for a firm price.
- Grade and specification. NiCr20Co13Mo4Ti3Al / 2.4654 / N07001, with AMS or customer specification
- Drawing, or finished dimensions with tolerances
- Quantity, and whether the order repeats
- Delivery condition. As forged, rough machined or finish machined
- Heat-treatment route. A for creep, B for tensile
- Melt route. VIM/VAR, VIM/ESR or EAF plus VOD plus ESR
- NDT requirement and acceptance class
- Certificate type, EN 10204 3.1 or 3.2, and destination port
Jiangyin Jiangnan Metal Co., Ltd.
- Open-die forging factory
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- +86 189 2135 9659
- sales@steelforgepieces.com
Enquiries are answered in English and Chinese. Drawings are treated as confidential and a non-disclosure agreement can be signed before quotation.
Supplier
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, in the Yangtze River delta forging cluster and within reach of the ports of Shanghai and Zhangjiagang. The works produces open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel-base superalloys, including NiCr20Co13Mo4Ti3Al (2.4654), Inconel, Incoloy, Hastelloy, Monel and Haynes grades.
Work is supplied to drawing with EN 10204 3.1 or 3.2 certification, ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, and full heat-number traceability. Enquiries reach the technical department directly on +86 189 2135 9659 or sales@steelforgepieces.com.
Related nickel superalloy grades
- Waspaloy
- Rene 41
- Inconel 625
- Inconel 600
- Inconel 601
- Inconel 617
- Inconel 690
- Inconel 693
- Inconel 725
- Inconel X-750
- Incoloy 800H
- Incoloy 800HT
- Incoloy 825
- Incoloy 901
- Incoloy 925
- Incoloy 945
- Hastelloy C-276
- Hastelloy C-22
- Hastelloy X
- Haynes 25
- Haynes 188
- Haynes 230
- Monel 400
- Monel K-500
- MP159
- MP35N
- Multimet N155
- Alloy 59
NiCr20Co13Mo4Ti3Al in other forged forms
Data sources
Composition, physical constants, heat-treatment cycles and stress-rupture data on this page follow the published mill and specification literature for UNS N07001 and W.Nr. 2.4654.
- Special Metals Corporation, Waspaloy technical bulletin SMC-011. Composition, physical constants, heat treatment, rupture data.
- SAE International. AMS 5704, 5706, 5707, 5708 and 5709 for bar, forgings and rings; AMS 5544 for sheet; AMS 5828 for welding wire.
- ASTM International. ASTM B637 and ASME SB-637, precipitation-hardening nickel alloy bar, forgings and forging stock.
- Bohler Edelstahl, L303 (2.4654 / N07001) datasheet. Restricted mill chemistry for aerospace product.
- Production records of Jiangyin Jiangnan Metal Co., Ltd. for forging ranges, machining and inspection practice.
The values are given for engineering guidance and are not a warranty of the properties of any particular forging. Acceptance values are those stated on the purchase order and on the material certificate.
Citation
Jiangyin Jiangnan Metal Co., Ltd. (2026). NiCr20Co13Mo4Ti3Al (2.4654 / UNS N07001 / Waspaloy) forging datasheet. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/NiCr20Co13Mo4Ti3Al.html
These tables may be reproduced with attribution to Jiangyin Jiangnan Metal Co., Ltd. and a link to this page. A plain-text version of this datasheet is available at NiCr20Co13Mo4Ti3Al.md.