2.4951 (NiCr20Ti) Forgings: Forged Rings, Shafts, Discs, Flanges and Tube Sheets in Alloy 75 / UNS N06075

Last updated: 10 August 2026. Reviewed by the Jiangyin Jiangnan Metal Co., Ltd. metallurgical engineering team. Sources.

Material no.

2.4951

UNS

N06075

Density

8.37 g/cm³

UTS (ann.)

750 MPa

Yield (ann.)

275 MPa

Elongation

42 %

E-modulus

206 GPa

Oxidation to

1,000 °C

What is 2.4951 / NiCr20Ti / Alloy 75?

2.4951 is a nickel-chromium alloy of the classic 80/20 type, strengthened by titanium carbides rather than by age hardening. Nickel provides the austenitic, non-magnetic matrix and resistance to reducing environments. About 20 % chromium forms the protective Cr₂O₃ scale that gives the alloy its oxidation and scaling resistance. The controlled carbon content together with 0.2 to 0.6 % titanium forms fine titanium carbides that stabilise grain size and add modest strength at temperature.

This has a direct consequence for specification: 2.4951 is not age-hardenable. There is no gamma prime hardening step, so the alloy arrives solution annealed and stays in that condition. It is therefore easy to forge, easy to weld, dimensionally stable in service and inexpensive relative to precipitation-hardened superalloys. It also means that above roughly 600 °C the design is governed by creep rather than by yield strength. Where a highly stressed hot component is required, the aluminium-bearing sister grade NiCr20TiAl (Nimonic 80A) is specified instead.

Typical forged parts produced in 2.4951 include furnace and heat-treatment fixtures, retorts and muffle components, gas turbine casing and combustion hardware, thermocouple and instrumentation sheaths, heat exchanger and pressure vessel components, and rings, discs and shafts for thermal process plant.

What is the equivalent of 2.4951?

This alloy appears under at least eight names. All of the designations below describe the same generic chemistry, and Jiangyin Jiangnan Metal Co., Ltd. accepts purchase orders written under any of them, cross-certifying the equivalents on a single material test certificate.

What is the chemical composition of 2.4951?

The composition below is the specification range Jiangyin Jiangnan Metal supplies against for 2.4951 forgings, to DIN 17744 and EN 10095 chemistry. The last column gives the reason each element is present.

Melt route. 2.4951 for forged parts is melted by EAF plus VOD, followed by ESR remelting. The ESR step is important for high-temperature service because it reduces sulphur and oxide inclusions, improves the soundness on which ultrasonic acceptance depends, and produces the directional solidification that keeps large rings free from centreline defects.

What are the mechanical properties of 2.4951?

Room-temperature properties in the solution-annealed condition, which is how forged 2.4951 is normally delivered:

How to read these values. They are typical figures for solution-annealed material and are the basis of our process control. They are not a guarantee for a specific part. The values that count contractually are those measured on test pieces from your own heat and reported on the EN 10204 certificate. For sections above about 200 mm, and for test pieces taken transverse to the grain flow, expect somewhat lower elongation. State the acceptance minima on the drawing and we will confirm them before accepting the order.

What are the physical properties of 2.4951?

Physical constants are typical published values for the NiCr20Ti / Alloy 75 chemistry, given for design orientation. Where a physical property is safety-critical, for example thermal expansion in a bolted hot joint, request measured values or the specific reference standard with the enquiry.

How hot can 2.4951 be used? Service temperature and creep

The answer depends on how heavily the part is loaded, so it is worth separating the two cases.

Because 2.4951 obtains its hot strength only from solid solution and carbides, its creep-rupture strength is modest by superalloy standards. For a furnace fixture that has to survive thermal cycling and be cheap to replace, high creep strength is not required and weldability, oxidation resistance and cost decide the choice. For a turbine bolt or blade the opposite applies, and Nimonic 80A, Waspaloy or Inconel 617 are the grades to consider.

Oxidation, corrosion and the limits of 2.4951

2.4951 performs well in air, combustion products and steam, and resists nitriding better than the iron-based heat-resisting steels. Its weaknesses follow from the chemistry: no molybdenum, no aluminium and modest silicon.

2.4951 compared with Nimonic 80A, Inconel 600, Inconel 601 and Incoloy 800H

These five grades are the ones most often weighed against each other for hot service. 2.4951 is the economical, weldable, oxidation-resistant baseline, and each alternative buys one specific property at a price.

What forged shapes are available in 2.4951?

Every shape below is produced from 2.4951 by open-die forging, hot ring rolling or upsetting, then solution annealed, machined to the level specified and tested. The sizes given are our qualified envelopes for this alloy class.

• Seamless rolled rings
• Contoured rolled rings
• Forged rings
• Gear ring blanks
• Forged shafts
• Eccentric shafts
• Spindles
• Forged bars, round, flat and square
• Forged discs and discs with hub
• Forged flanges
• Tube sheets
• Forged sleeves
• Bushings
• Forged tubes and pipes
• Forged blocks and blanks
• Nozzles
• Valve bodies and bonnets
• Valve seat rings
• Valve stems
• Forged wheels
• Manifolds
• Rolls
• Near-net-shape forgings to drawing

Where is 2.4951 used? Applications by industry

How is 2.4951 forged and heat treated?

Forging

Nickel-chromium alloys are less forgiving than steel. The workable temperature window is narrow, the alloy work-hardens quickly, and sulphur or lead picked up from dirty tooling causes hot shortness. Our practice for 2.4951 is as follows.

• Heating. Charge into a furnace at moderate temperature and soak. Heavy sections should not be shock-heated. The furnace atmosphere must be low in sulphur, since sulphur-bearing fuel will embrittle the surface.
• Forging window. Start at approximately 1,150 °C and finish the last blows above about 950 °C. Forging below that range risks cracking and leaves an uneven, partly worked structure.
• Reduction. Multi-step incremental reduction with reheats as required, aiming at a forging ratio of at least 4:1 to break down the as-cast structure and give uniform grain size.
• Finishing. Light finishing reductions below the recrystallisation temperature promote a fine grain, while heavy reduction just before the end promotes a coarse one. State on the drawing if a grain-size class is required.
• Cooling. Air cool after the final blow, then solution anneal. The forging heat should not be relied on to do the annealing.

Heat treatment

2.4951 has one standard cycle: solution anneal at 1050 °C, hold 30 to 60 minutes for forged sections and 5 to 10 minutes for sheet, then air cool. There is no ageing step because the alloy is not precipitation hardenable. Cooling should be brisk enough through 750 to 550 °C to limit grain-boundary carbide precipitation. Still-air cooling is normally sufficient for the section sizes we forge, and forced air is used on heavy rings.

Welding, machining and forming 2.4951

Welding

2.4951 welds readily by GTAW, GMAW, SMAW and plasma processes, which is an advantage over age-hardening grades that are prone to strain-age cracking. Weld in the solution-annealed condition. Matching or Ni-Cr filler is used, and Inconel type 82 or 182 fillers are common where matching wire is unavailable. Keep the interpass temperature low, clean the joint faces thoroughly of sulphur-bearing marker, grease and cutting fluid, and re-solution-anneal after welding where the code or the service temperature requires full property recovery. Preheat is not normally required.

Machining

Machining practice follows austenitic superalloy rules rather than steel practice. The alloy work-hardens quickly, so use a rigid setup, sharp positive-rake carbide tooling, slow to moderate speed with heavy positive feed, a cut deep enough to get under the previously work-hardened layer, and generous flood coolant. Dwelling or rubbing must be avoided. Typical turning speed with coated carbide is 20 to 40 m/min in the annealed condition. Where a large amount of stock has to be removed, ordering the forging rough machined at our works is usually the cheaper route.

Forming

Cold forming is possible but the work-hardening rate is high, and interstage annealing at 1050 °C is required for anything beyond light forming. Hot forming follows the same window as forging.

2.4951 production capability at Jiangyin Jiangnan Metal

Process flow from raw material to certificate

Equipment used for this grade

Standards, inspection and certificates for 2.4951 forgings

Third-party inspection. If the project requires an EN 10204 3.2 certificate, state it on the enquiry rather than on the purchase order. Witnessed heat treatment and witnessed testing add hold points to the schedule, and a 3.2 requirement discovered after production has started typically costs two to four weeks.

How to specify a 2.4951 forging order

Seven pieces of information turn an enquiry into a firm quotation. A missing item is the usual reason a quotation later changes.

1. Designation. Write 2.4951 / NiCr20Ti (UNS N06075) together with the standard you are buying to. Ordering by the Nimonic 75 brand name alone should be avoided, since it is a Special Metals trademark and implies their material.
2. Shape and finished size. Ring OD x ID x height, shaft diameter x length, disc diameter x thickness, or attach the drawing. State whether the forging is to be delivered as forged, rough machined or finish machined.
3. Delivery condition. Solution annealed at 1050 °C for 30 to 60 minutes then air cooled is standard. State any different cycle imposed by the specification.
4. Non-destructive testing. Which standard (EN 10228-3, SEP 1921 or ASTM A388), which acceptance class, and any surface NDT.
5. Mechanical testing. Room-temperature tensile only, or elevated-temperature tensile and stress rupture as well, plus sampling direction and location and any grain-size or intergranular corrosion requirement.
6. Certificate. EN 10204 3.1, or 3.2 with a named third-party surveyor.
7. Commercial terms. Quantity, marking, packing, Incoterms and destination port.

Eight recurring problems on 2.4951 enquiries

Drawing callout template for 2.4951

The block below can be copied into the material box of a drawing. It removes most of the ambiguity that generates technical queries during quotation.

MATERIAL:      2.4951 / NiCr20Ti (UNS N06075, Alloy 75)
               to DIN 17744 / EN 10095 chemistry
CONDITION:     Solution annealed 1050 deg C, 30-60 min, air cool
MELT ROUTE:    EAF + VOD + ESR
FORGING:       Open-die forged / ring rolled, forging ratio min 4:1
               Finish forging temperature above 950 deg C
NDT:           UT to EN 10228-3 quality class ___ (or SEP 1921 class ___)
               PT to EN ISO 3452 on machined surfaces
TESTING:       Tensile at RT per ISO 6892-1; report Rm, Rp0.2, A
               Elevated-temperature tensile at ___ deg C per ISO 6892-2 (if required)
               Grain size per ASTM E112, class ___ (if required)
CERTIFICATE:   EN 10204 3.1  (or 3.2 witnessed by ___________)
MARKING:       Heat number, material designation, drawing number,
               low-stress stamp or vibro-etch on non-functional surface
SURFACE:       Rough machined, allowance ___ mm per surface

Glossary

2.4951

European material number (Werkstoffnummer) for the NiCr20Ti nickel-chromium alloy, equivalent to UNS N06075 and commonly called Alloy 75.

NiCr20Ti

DIN chemical-symbol designation: nickel base, about 20 % chromium, titanium addition.

UNS N06075

Generic Unified Numbering System designation for the same chemistry.

Alloy 75

Generic, non-trademarked industry name for this grade.

Nimonic 75

Registered trademark of Special Metals Corporation for their version of this chemistry. Independent producers supply the generic designations instead.

Solid-solution strengthening

Strength gained from alloying elements dissolved in the matrix rather than from precipitates. It is stable but modest, which is why 2.4951 needs no ageing treatment.

Gamma prime

The Ni3(Al,Ti) precipitate that gives age-hardening superalloys such as Nimonic 80A their hot strength. 2.4951 has too little titanium and no aluminium to form it in quantity.

Solution annealing

Heating to 1050 °C to dissolve precipitates and recrystallise the worked structure, then air cooling. The standard delivery condition for 2.4951 forgings.

Creep-rupture strength

The stress that causes failure after a stated time at a stated temperature, and the correct design basis above roughly 600 °C.

ESR

Electroslag remelting, a secondary melting route that lowers sulphur and inclusions and improves soundness, which matters for forging quality in high-temperature alloys.

Forging ratio

The degree of hot work applied to the ingot or billet. A ratio of at least 4:1 is used to break down the cast structure and refine grain size.

EN 10228-3

European standard for ultrasonic testing of forgings, with quality classes defining acceptable indication sizes.

SEP 1921

German ultrasonic acceptance specification for forgings, widely referenced in European procurement.

EN 10204 3.1 and 3.2

Certificate types. 3.1 is issued by the manufacturer's independent inspection function. 3.2 is countersigned by a third-party surveyor or the customer's representative.

Seamless rolled ring

A ring produced by piercing a billet and expanding it on a ring mill, giving circumferential grain flow and no weld seam.

Frequently asked questions about 2.4951

References

1. DIN 17744, Wrought nickel alloys with molybdenum and chromium, chemical composition, Deutsches Institut fur Normung.
2. DIN 17742, Wrought nickel alloys with chromium, chemical composition, Deutsches Institut fur Normung.
3. EN 10095, Heat resisting steels and nickel alloys, CEN, Brussels.
4. EN 10204:2004, Metallic products, types of inspection documents, CEN.
5. EN 10228-3, Non-destructive testing of steel forgings, Part 3, ultrasonic testing, CEN.
6. SEP 1921, Ultrasonic testing of steel forgings, acceptance classes, Stahl-Eisen-Prufblatt, VDEh.
7. ASTM A388/A388M, Standard practice for ultrasonic examination of steel forgings, ASTM International.
8. ISO 6892-1 and ISO 6892-2, Metallic materials, tensile testing at room and elevated temperature, ISO, Geneva.
9. ASTM E8/E8M and ASTM E21, Tension testing of metallic materials, ASTM International.
10. ASTM E112, Standard test methods for determining average grain size, ASTM International.
11. BS 3072 to 3076, Nickel and nickel alloys, sheet, plate, bar and forgings, British Standards Institution.
12. Special Metals Corporation, Nimonic alloy 75 technical datasheet.
13. ASM Handbook, Volume 1, Properties and Selection: Irons, Steels, and High-Performance Alloys, ASM International, Materials Park, OH, sections on nickel-base heat-resisting alloys.
14. ASM Specialty Handbook: Heat-Resistant Materials, J.R. Davis (ed.), ASM International.

Standards are cited without revision numbers because revisions change. For procurement, always reference the revision in force at the contract date. Trademarks are the property of their respective owners.

Related grades and forged products

• Nimonic 75
• Nimonic 80A
• Inconel 600
• Inconel 601
• Inconel 617
• Inconel 625
• Incoloy 800H
• Incoloy 800HT
• Haynes 230
• Hastelloy X
• Waspaloy
• Forged and rolled rings
• Forged discs
• Forged tube sheets
• Forged valve seat rings
• Haynes 188 forged rings
• Waspaloy forged pipes
• All forged products