Nickel superalloy · Gamma-prime hardened · Open-die forgings

NiCr19Co14Mo4Ti Forgings: W.Nr. 2.4654 / UNS N07001

Published: 12 May 2022 · Last updated: 23 August 2026 · Technically reviewed by the Jiangyin Jiangnan Metal Co., Ltd. Metallurgical Engineering Team

Werkstoff

2.4654

UNS

N07001

Density

8.19 g/cm³

Melting range

1330–1360 °C

Rotating limit

650 °C

Static limit

870 °C

Aged hardness

34–44 HRC

Max piece

8,000 kg

What is NiCr19Co14Mo4Ti?

NiCr19Co14Mo4Ti is a precipitation-hardening nickel-chromium-cobalt-molybdenum superalloy designated W.Nr. 2.4654 in the German system and UNS N07001 in the American one. The DIN name is written directly from the chemistry: nickel base, 19% chromium, 14% cobalt, 4% molybdenum, with titanium as the principal hardening addition.

Two mechanisms give the alloy its strength, and they operate at different scales. The matrix is strengthened in solution by molybdenum, cobalt and chromium, which raise the resistance of the nickel lattice to dislocation motion at temperature. On top of that, ageing precipitates a fine dispersion of coherent gamma-prime Ni₃(Al,Ti), typically occupying 20–25% of the volume. Gamma prime is what carries the load above 600 °C, and its stability is the whole argument for choosing this grade.

That last point is worth stating plainly, because it is the reason engineers move to this alloy from a cheaper one. Inconel 718, the default high-temperature nickel alloy in most shops, is hardened by metastable gamma double prime, Ni₃Nb, which begins to coarsen and revert above roughly 650 °C. The gamma prime in NiCr19Co14Mo4Ti has a solvus near 1,000 °C and does not do that. Below 650 °C, 718 is the better commercial answer. Above about 700 °C it is simply the wrong material, and NiCr19Co14Mo4Ti is one of the standard replacements.

Chromium at 18–21% gives the oxidation and hot-corrosion resistance. Performance has been good in gas-turbine combustion atmospheres and in salt spray, and it holds up under frequent thermal cycling rather than only in still air. Corrosion resistance is at its best in the solution-treated condition.

Supplier quick facts

Is NiCr19Co14Mo4Ti the same as Waspaloy? A note on names

Yes. NiCr19Co14Mo4Ti, W.Nr. 2.4654, UNS N07001, Alloy 685, GH4738, NC20K14, MSRR 7192, BS HR 201 and the Waspaloy trade name all describe the same nominal chemistry. Which name appears on a drawing usually depends on where and when the drawing was produced, not on any difference in the material.

If your drawing carries the trade name and you would rather read that page, see our Waspaloy forgings page, which covers the same alloy from the AMS and aerospace-specification side.

What forged products are available in NiCr19Co14Mo4Ti?

We produce this grade by three routes, chosen by geometry and quantity. Open-die forging handles shafts, blocks, large discs and tube sheets, where single-piece size matters more than repeatability. Seamless ring rolling produces rings from 200 mm to 2,500 mm outside diameter with continuous circumferential grain flow. Near-net-shape forging is used where a die profile removes 30–50% of the rough machining. That saving matters more on this alloy than on almost any other, because the material is expensive per kilogram and slow to cut.

• Seamless rolled rings
• Forged rings
• Forged flanges
• Forged discs & blanks
• Forged shafts & spindles
• Forged round bars
• Forged flat bars & blocks
• Forged sleeves & bushings
• Forged tube sheets
• Forged hollows & tubes
• Forged gear blanks
• Forged valve bodies & seat rings
• Near-net-shape parts

Equivalent designations and specifications

Every designation below refers to the same nominal chemistry. We accept purchase orders under all of them and cross-list the equivalents on the material certificate.

What is the chemical composition of NiCr19Co14Mo4Ti?

Two chemistry bands are in circulation for this alloy and they are not interchangeable. The general limits are those of UNS N07001 and W.Nr. 2.4654. Aerospace practice under the AMS specifications tightens several elements considerably and adds trace limits on lead, bismuth, selenium and silver, because those elements segregate to grain boundaries and destroy stress-rupture ductility at parts-per-million levels.

Our melting practice

Jiangyin Jiangnan Metal Co., Ltd. melts NiCr19Co14Mo4Ti by EAF + VOD followed by ESR as standard. Vacuum oxygen decarburisation controls carbon and dissolved gases; electroslag remelting refines the inclusion population and produces the directionally solidified ingot that forges cleanly. For aerospace-qualified work we source VIM + VAR double-vacuum stock instead. That route is what the restricted trace-element limits in Table 5 practically require, and it is what most AMS revisions call up. State the melting route at RFQ stage, because it changes both price and lead time. Full ladle and product analyses are reported on the EN 10204 certificate.

What are the physical properties of NiCr19Co14Mo4Ti?

Data note. Density, melting range, modulus, expansion and resistivity are well established for this chemistry and can be used directly for design screening. Values marked "typical" or "≈" vary with heat, section size and condition. Where any physical value is contractually important, state it on the purchase order and we will report the measured result on the material certificate.

What are the mechanical properties of NiCr19Co14Mo4Ti?

Room-temperature properties depend almost entirely on the delivery condition, and the difference between solution-treated and fully aged material is large enough that the two should never be confused on a purchase order. Solution-treated material is soft enough to machine economically; fully aged material is not, but it is what goes into service.

Stress-rupture acceptance is normally verified by test rather than inferred: a specimen held at 816 °C (1500 °F) under an applied stress in the region of 276–328 MPa (40–47.5 ksi), depending on the AMS revision, must not rupture in less than 23 hours. Grain-size uniformity is separately controlled, with segregated coarse or fine regions typically limited to 20% of any field at 100× magnification.

Stress-rupture and creep strength

For a part that runs hot, the rupture curve, not the room-temperature tensile figure, is the property that sizes it. The values below are for the creep-optimised heat treatment (solution 1080 °C, stabilise 845 °C, age 760 °C).

The shape of that curve is the practical message. Between 649 °C and 870 °C the load-carrying capacity falls by a factor of roughly five and a half, and more than half of that loss happens in the first 110 degrees. A design that is comfortable at 650 °C can be marginal at 760 °C without any change to the part.

Service temperature limits: which number applies to your part

This alloy is quoted with three different maximum temperatures and they answer three different questions. Getting them confused is the commonest specification error on the grade.

How is NiCr19Co14Mo4Ti heat treated?

NiCr19Co14Mo4Ti is heat treated in three steps: solution treatment, stabilisation, then age hardening. There are two accepted routes, and they produce measurably different parts. Route A maximises creep and stress-rupture strength. Route B maximises room- and high-temperature tensile strength. Neither is a default: the route must be stated on the order.

Two practical points. Scale formed during heat treatment in an oxidising atmosphere is removed by acid pickling or mechanically, so allow for it in the machining stock. The long stabilisation soak in Route A (24 hours) is not optional padding: it conditions the grain-boundary carbide distribution that carries creep resistance, and shortening it to match Route B will not give Route A properties.

How is NiCr19Co14Mo4Ti forged?

NiCr19Co14Mo4Ti is hot worked between about 980 °C and 1170 °C (1800–2140 °F). Below roughly 980 °C the alloy work hardens fast enough to crack; above about 1180 °C it becomes hot short as grain-boundary constituents begin to melt. That leaves a working window of about 190 °C, which is narrow. For comparison, a low-alloy steel gives the forge two or three times as much room.

The practical consequences show up in cost and schedule rather than in the drawing:

• More reheats. A piece that a steel forge would finish in two heats commonly takes four or five in this alloy. Each reheat is furnace time and scale loss.
• Higher press loads. Flow stress at forging temperature is several times that of carbon steel at the same temperature, which is why heavy sections go on the hydraulic press rather than under a hammer.
• Tight pyrometry. Furnace control and stock temperature measurement have to be genuinely accurate, because the penalty on both sides of the window is scrap rather than rework.
• Reduction ratio matters. At least 4:1 total reduction from the ingot is used to break down the as-cast structure and give a uniform recrystallised grain size.
• Furnace atmosphere. Sulfur pick-up from fuel or die lubricant causes grain-boundary hot shortness. Furnaces are run clean and neutral to slightly reducing.

Machining and welding NiCr19Co14Mo4Ti

Machining

NiCr19Co14Mo4Ti is among the more difficult superalloys to machine. Three properties combine against the cutting edge: rapid work hardening, low thermal conductivity that keeps heat in the tool rather than in the chip, and abrasive carbides in the microstructure.

• Machine soft where possible. Rough at 20–25 HRC in the solution-treated condition, then stabilise and age. This is the largest single cost lever on the part.
• Rigidity above all. Short overhangs, heavy toolholders, minimum stick-out. Chatter work-hardens the surface and the next pass has to cut through it.
• Low speed, heavy positive feed. Coated carbide at conservative surface speeds with a feed heavy enough to cut beneath the previously hardened layer.
• Never dwell. A tool that stops feeding while still in contact glazes the surface and work-hardens a layer that will destroy the next edge.
• Replace edges early. Run inserts to a set time rather than to failure. A broken edge in an aged superalloy part often means a scrapped forging.
• Flood coolant, high concentration and pressure. Through-tool delivery wherever the machine supports it.

Welding

NiCr19Co14Mo4Ti compared with 718, Rene 41, Nimonic 263 and X-750

The 718 comparison is the one that decides most projects. The two alloys have the same density and similar chromium, and 718 is a third cheaper and far easier to weld and machine. Up to about 650 °C, 718 wins on every commercial measure. Between 650 °C and 705 °C the gamma-double-prime in 718 starts coarsening and the curves cross. Above roughly 700 °C the comparison is not close, and NiCr19Co14Mo4Ti keeps a substantial strength and stability advantage. If your design sits in the 650–700 °C band, the deciding factors are usually weldability, section size and expected life rather than raw strength.

Where is NiCr19Co14Mo4Ti used?

The alloy was developed for gas turbine engine hardware and that remains its centre of gravity. Everything below relies on the same combination: usable strength and creep resistance between 650 °C and 870 °C, with oxidation and hot-corrosion resistance to match.

NiCr19Co14Mo4Ti production capability

Jiangyin Jiangnan Metal Co., Ltd. operates an open-die forging and ring-rolling plant in Jiangyin, Jiangsu Province, China, employing approximately 460 people including 9 senior engineers and 32 intermediate engineers. NiCr19Co14Mo4Ti is produced on the same equipment as the rest of our nickel superalloy range.

Standards, testing and certification

NiCr19Co14Mo4Ti orders are produced and certified against the specifications below. The chemistry specification is normally UNS N07001 / W.Nr. 2.4654, with an AMS or ASTM specification named on the order; the inspection-document type is normally EN 10204 3.1.

• UNS N07001
• W.Nr. 2.4654
• DIN NiCr19Co14Mo4Ti
• ASTM B637 (Alloy 685)
• AMS 5704
• AMS 5706
• AMS 5707
• AMS 5708
• AMS 5709
• ISO 9722 / 9723 / 9724 / 9725
• EN 10204 3.1
• EN 10204 3.2
• EN 10228-3 (UT)
• SEP 1921 (UT)
• ASTM A388 (UT)
• ASTM E112 (grain size)
• ISO 9001:2015

What appears on the certificate

• Heat number, with full ladle and product chemical analysis
• Melting route: EAF + VOD + ESR, or VIM + VAR where specified
• Mechanical test results: tensile, 0.2% proof, elongation, reduction of area and hardness on coupons from the delivered heat
• Complete heat-treatment record: solution, stabilisation and ageing temperatures, soak times, cooling media, from calibrated charts
• Ultrasonic examination report to the ordered standard and acceptance class
• ASTM E112 grain size and macroetch report for grain flow, where ordered
• Stress-rupture test result, where the specification requires it
• Dimensional inspection report
• Cross-listed equivalent designations (NiCr19Co14Mo4Ti / 2.4654 / N07001 / Alloy 685)

Quality gates

Every NiCr19Co14Mo4Ti order passes six mandatory hold points at which production cannot continue without QA sign-off: raw-material chemistry verification, forging temperature compliance, post-forging ultrasonic examination, heat-treatment chart approval, mechanical test acceptance, and final NDE plus dimensional inspection. Customer-witnessed hold points can be added at no charge. Any out-of-specification finding raises a formal non-conformance report within 24 hours, with root-cause analysis inside five working days and the proposed disposition sent to you before any rework is carried out.

How to specify a NiCr19Co14Mo4Ti forging order

This grade carries two specification decisions that most alloys do not: the melting route and the heat-treatment route. Neither is implied by the alloy name, and both change the delivered part. The eight steps below remove the ambiguity that causes most disputes.

1. Name the grade generically. "NiCr19Co14Mo4Ti / W.Nr. 2.4654 / UNS N07001" rather than a trade name alone.
2. State the governing specification and revision. AMS 5704 for forgings, ASTM B637 for bars and forging stock, and so on, with the revision letter.
3. Specify the melting route. EAF + VOD + ESR, or VIM + VAR double vacuum. This drives both price and lead time.
4. Specify the delivery condition. Solution treated, or solution + stabilised + aged, with the required hardness band.
5. Define grain flow and grain size. Circumferential or radial flow for rings and discs; ASTM grain size and macroetch acceptance.
6. Define non-destructive examination. UT to EN 10228-3, SEP 1921 or ASTM A388 with acceptance class; penetrant examination on machined surfaces.
7. Specify certification. EN 10204 3.1 or 3.2. For 3.2, name the third-party inspection body.
8. State quantity, delivery and marking. Piece count, required date, Incoterms, destination port, heat-number marking requirement.

Recommended drawing callout

Ten mistakes when ordering NiCr19Co14Mo4Ti forgings

1. Taking the highest service temperature off the datasheet. 1038 °C is an oxidation figure with no load-bearing meaning. A rotating part is limited to about 650 °C.
2. Leaving the heat-treatment route unstated. Route A and Route B produce different parts. Silence gets you the supplier's default, which may not be yours.
3. Leaving the melting route unstated. ESR and VIM+VAR material both meet the general chemistry, but only the vacuum route reliably meets the restricted trace-element limits.
4. Quoting the alloy name without the AMS number and revision. AMS 5704, 5706, 5707, 5708 and 5709 are not interchangeable.
5. Ordering fully aged material that then needs heavy machining. Order solution treated, rough machine at 20–25 HRC, then age. It is usually far cheaper.
6. Designing a structural weld into a hot rotating part. This alloy is strain-age cracking sensitive. Either move the weld or move the grade.
7. Accepting machined-from-plate in place of a rolled ring. Same chemistry, different grain flow, worse creep and fatigue life at the same hardness.
8. Assuming 718 practice transfers. Forging window, machining parameters and weld procedure are all different. So is the price.
9. Mixing heats within a matched assembly. Specify single heat where several parts must behave identically.
10. Omitting the stress-rupture test when the specification calls for it. It is the test that actually verifies the high-temperature capability you are paying for.

Glossary

NiCr19Co14Mo4Ti

DIN chemical-symbol designation for the age-hardenable nickel-chromium-cobalt-molybdenum superalloy W.Nr. 2.4654 / UNS N07001.

W.Nr. 2.4654

Werkstoffnummer, the German material number for this alloy. Written as 2.4654 or 1.2.4654 in some catalogues.

UNS N07001

Unified Numbering System designation. The generic, brand-free name to put on a purchase order.

Alloy 685

Grade designation used for this chemistry in ASTM B637 and in legacy AISI practice.

GH4738

Chinese superalloy designation for the same chemistry, also written GH738.

Gamma prime (γ′)

Coherent ordered FCC precipitate of composition Ni₃(Al,Ti) that provides the high-temperature strength of this alloy. Volume fraction is typically 20–25%.

Gamma double prime (γ″)

The metastable Ni₃Nb precipitate that strengthens Inconel 718. It coarsens and reverts above roughly 650 °C, which is the reason 718 gives way to γ′ alloys at higher temperature.

Gamma-prime solvus

The temperature above which gamma prime dissolves back into the matrix, near 1000–1030 °C for this alloy. It sets the solution-treatment temperature and the useful upper strength limit.

Solution treatment

High-temperature soak that dissolves gamma prime and produces a uniform matrix, leaving the alloy soft at 20–25 HRC and in its best corrosion-resistant condition.

Stabilisation

Intermediate soak at 845 °C that conditions the grain-boundary carbide distribution. The 24-hour version in Route A is what gives creep resistance.

Age hardening

Final soak at 760 °C for 16 hours that precipitates gamma prime and raises hardness to 34–44 HRC.

Stress rupture

Failure under constant load at temperature after a period of time. The 1,000-hour rupture strength is the figure that sizes hot parts.

Strain-age cracking

Cracking that occurs in the heat-affected zone of a weld when gamma prime precipitates during post-weld heating while residual stress is still present. The reason this alloy is welded solution treated and re-solution treated afterwards.

Hot shortness

Loss of ductility at forging temperature caused by melting of low-melting grain-boundary constituents. In this alloy it sets the upper forging limit near 1180 °C.

ESR

Electroslag remelting. Secondary melting that refines inclusion content and produces a directionally solidified ingot suited to forging.

VIM + VAR

Vacuum induction melting followed by vacuum arc remelting. The double-vacuum route required for aerospace-restricted trace-element limits.

Seamless rolled ring

A ring produced by piercing a forged billet and expanding it on a radial-axial ring mill, giving continuous circumferential grain flow and better creep and fatigue life than a ring machined from plate.

EN 10204 3.1 / 3.2

Inspection document types. 3.1 is a mill certificate issued by the manufacturer's own independent inspection department; 3.2 is countersigned by an independent third party nominated by the purchaser.

Frequently asked questions: NiCr19Co14Mo4Ti (2.4654 / UNS N07001)

Technical references

Chemistry, physical-property, mechanical-property and heat-treatment data on this page are drawn from the published standards and engineering references below. Test results reported on our material certificates are independent and traceable to calibrated laboratory equipment.

1. Special Metals Corporation, Waspaloy, technical bulletin SMC-011. Physical constants, heat-treatment schedules and 1,000-hour stress-rupture data.
2. SAE AMS 5704, Nickel Alloy, Corrosion and Heat Resistant, Forgings, SAE International.
3. SAE AMS 5706 / 5707 / 5708 / 5709, Bars, Forgings and Rings, SAE International.
4. SAE AMS 5544 (sheet, strip and plate), AMS 5586 (tubing) and AMS 5828 (welding wire), SAE International.
5. ASTM B637, Standard Specification for Precipitation-Hardening and Cold-Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service, ASTM International.
6. ISO 9722 / 9723 / 9724 / 9725, Nickel and nickel alloys — composition and forms of wrought products, ISO.
7. EN 10204:2004, Metallic products — Types of inspection documents, CEN, Brussels.
8. EN 10228-3, Non-destructive testing of steel forgings — Part 3: Ultrasonic testing, CEN.
9. SEP 1921, Ultrasonic testing of steel forgings, Stahl-Eisen-Prüfblatt.
10. ASTM A388, Standard Practice for Ultrasonic Examination of Steel Forgings, ASTM International.
11. ASTM E112, Standard Test Methods for Determining Average Grain Size, ASTM International.
12. ASM Specialty Handbook: Nickel, Cobalt and Their Alloys, J. R. Davis (ed.), ASM International.
13. ASM Handbook, Volume 14A: Metalworking: Bulk Forming, ASM International, chapters on superalloy forging.
14. Sims, Stoloff & Hagel, Superalloys II, Wiley. Gamma-prime strengthening and stability.
15. Donachie & Donachie, Superalloys: A Technical Guide, 2nd ed., ASM International.

Standards cited are the revisions known to us at the time of the last page review. For procurement, always reference the revision in force at the contract date. All trademarks referenced belong to their respective owners.

Reuse of the property data. The tabulated composition, physical, mechanical, stress-rupture and heat-treatment data on this page is published under the Creative Commons Attribution 4.0 licence. You may copy, republish and build on it, including in specifications and reports, provided the source is credited as Jiangyin Jiangnan Metal Co., Ltd., this page.

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