Nickel-base superalloy, AFNOR NCK20D
NCK20D Forgings: Nimonic 263 / UNS N07263 / W.Nr. 2.4650
Open-die forged and seamless rolled NCK20D rings, flanges, shafts, discs, sleeves, bushings, tube sheets and bars, made to your drawing in Jiangyin, China.
Grade identification
- AFNOR
- NCK20D
- UNS
- N07263
- Werkstoff
- 2.4650
- DIN chemical
- NiCo20Cr20MoTi
- Trade name
- Nimonic 263
- Also sold as
- Haynes 263, C-263
NCK20D is the AFNOR designation for an age-hardenable nickel-cobalt-chromium-molybdenum superalloy. The same material is sold as Nimonic 263, Haynes 263 and Alloy C-263, and is listed as UNS N07263, W.Nr. 2.4650 and DIN NiCo20Cr20MoTi. Nominal chemistry is 20 % cobalt, 20 % chromium and 6 % molybdenum, balance nickel. Rolls-Royce developed it in 1971 to replace Nimonic 80A in welded gas turbine assemblies. Combined aluminium and titanium is held to 2.40-2.80 %, which is why it does not suffer the strain-age cracking common in Waspaloy and Rene 41.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge NCK20D to customer drawings: seamless rolled rings, forged rings, flanges, shafts, discs, sleeves, bushings, tube sheets and bars. Material is melted by EAF + VOD with ESR remelting, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, and certified to EN 10204 3.1 or 3.2. Phone +86 189 2135 9659, email sales@steelforgepieces.com.
NCK20D equivalent grades and specifications
Purchase orders for this alloy arrive under six different names, depending on whether the buyer works from a French, American, German or British specification. All of them refer to the same chemistry, and we quote against any of them.
| Standard or source | Designation | Notes |
|---|---|---|
| AFNOR (France) | NCK20D | The designation used on this page |
| UNS (USA) | N07263 | Most common in Western purchase orders |
| Werkstoff / EN | 2.4650 | European material number |
| DIN 17744 | NiCo20Cr20MoTi | German chemical designation |
| Trade name | Nimonic 263 | Originated with Rolls-Royce, 1971 |
| Trade names | Haynes 263, C-263 | Also sold as Nicrofer 5120 CoTi |
| AMS (bar) | AMS 5886 | Solution treated and aged bar |
| AMS (sheet, plate) | AMS 5872 | Sheet, strip and plate |
| British | BS HR10, HR206 | Bar and sheet respectively |
| EN 10302 | NiCo20Cr20MoTi | Creep-resisting steels and nickel alloys |
Designations are given for identification only. Order against the specification and revision named on your own drawing or purchase order.
NCK20D chemical composition
Composition to DIN 17744 and UNS N07263, in weight percent. Nickel is the balance, normally around 51 %.
| Element | Min | Max | Role in the alloy |
|---|---|---|---|
| Nickel (Ni) | Balance, approx. 51 | Austenitic matrix | |
| Cobalt (Co) | 19.00 | 21.00 | Solid-solution and creep strength |
| Chromium (Cr) | 19.00 | 21.00 | Oxidation and hot-corrosion resistance |
| Molybdenum (Mo) | 5.60 | 6.10 | Solid-solution strengthening |
| Titanium (Ti) | 1.90 | 2.40 | Gamma prime former |
| Aluminium + Titanium | 2.40 | 2.80 | Held low on purpose, the key to weldability |
| Carbon (C) | 0.04 | 0.08 | Grain-boundary carbides |
| Aluminium (Al) | - | 0.60 | Gamma prime former |
| Iron (Fe) | - | 0.70 | Residual |
| Manganese (Mn) | - | 0.60 | Residual |
| Silicon (Si) | - | 0.40 | Residual, from deoxidation |
| Copper (Cu) | - | 0.20 | Residual |
| Sulphur (S) | - | 0.010 | Impurity, kept low for hot ductility |
| Boron (B) | - | 0.005 | Grain-boundary strengthening |
| Lead (Pb) | - | 0.0020 | Tramp element limit |
| Silver (Ag) | - | 0.0005 | Tramp element limit |
| Bismuth (Bi) | - | 0.0001 | Tramp element limit |
Trace-element limits follow normal Nimonic 263 and AMS 5886 practice. Check against the revision of the specification called out on your drawing.
NCK20D mechanical properties
Properties change a great deal with heat treatment, so the delivery condition matters as much as the grade. We ship solution annealed when the customer still has forming or welding to do, and solution treated plus aged when the part goes straight into service.
| Condition | 0.2 % proof stress | Tensile strength | Elongation |
|---|---|---|---|
| Solution annealed1150 °C, water quench | 250-350 MPa 36-51 ksi |
700-800 MPa 102-116 ksi |
40-55 % |
| Solution treated and agedplus 800 °C for 8 h, air cool | 580 MPa min 84 ksi min |
1000 MPa min 145 ksi min |
15-25 % |
Typical values, for enquiry screening rather than design. Acceptance values depend on section size, test direction and the governing specification, and are reported on the mill certificate for each heat.
Physical properties
| Property | Value |
|---|---|
| Density | 8.36 g/cm³ (0.302 lb/in³) |
| Melting range | 1300-1355 °C |
| Maximum continuous service temperature | approx. 850 °C |
| Oxidation resistance | up to approx. 1000 °C |
| Hot working range | 950-1150 °C |
| Modulus of elasticity at 20 °C | approx. 224 GPa |
| Magnetic response | Non-magnetic, annealed or aged |
NCK20D forging shapes and size range
All shapes below are open-die forged or ring-rolled to drawing. There is no stock catalogue. Send dimensions or a drawing and we quote against it.
| Form | Size range | Typical use |
|---|---|---|
| Seamless rolled rings | OD 200-4000 mm | Turbine casings, combustor rings |
| Forged rings | OD 100-2500 mm | Valve seat rings, retaining rings |
| Forged flanges | OD up to 3000 mm | Pressure vessels, heat exchangers |
| Shafts and spindles | dia. 50-800 mm | Turbines, compressors, gearboxes |
| Discs and blanks | dia. up to 2000 mm | Turbine discs, gear blanks |
| Sleeves and bushings | OD 80-1500 mm | Subsea and compressor assemblies |
| Tube sheets | dia. up to 3000 mm | Shell-and-tube heat exchangers |
| Round and step bars | dia. 30-900 mm | Machining stock, valve stems |
| Forged pipes and hollow bars | OD up to 1500 mm | Pressure piping, nozzles |
| Single-piece weight | 5 kg to 20 000 kg | All forms |
Sizes shown are the working envelope. The practical limit for any one part depends on geometry and reduction ratio, so check with our engineering team before designing to the extremes of this range.
How we make an NCK20D forging
- MeltingEAF and VOD, then ESR remelting. This is what keeps inclusion content and segregation down.
- CoggingIngot broken down inside the 950-1150 °C window.
- Forging or ring rollingOpen-die forged, or rolled on the ring mill. Reduction ratio is controlled and recorded.
- Heat treatmentSolution treatment near 1150 °C, water quench. Ageing at 800 °C for 8 h where the order calls for it.
- Rough machiningProof machining to strip scale and open up the section for inspection.
- Non-destructive testingUltrasonic to EN 10228-3, SEP 1921 or ASTM A388. PT and MT if you need them.
- CertificationResults go out as EN 10204 3.1. Third-party 3.2 on request.
Where NCK20D forgings are used
NCK20D is chosen where a part has to be welded or fabricated first and then run hot. Its strength at temperature is lower than Waspaloy and Rene 41, but it is much easier to form and join, which is why most fabricated turbine hardware uses it. The bulk of our enquiries are for seamless rolled rings, forged tubes and forged sleeves.
| Industry | Typical NCK20D parts |
|---|---|
| Aero and industrial gas turbines | Combustion chambers, transition liners, exhaust cones, casings, seamless rolled rings |
| Pressure equipment | Forged tubes, tube sheets and flanges for pressure vessels, air receivers and shell-and-tube heat exchangers |
| Process plant | Columns, towers, tanks, silos, preheaters and process modules running in the 600-850 °C range |
| Oil, gas and subsea | Sleeves, bushings, discs and wellhead components for deepwater production systems |
| Valves | Stems, seat rings, blocks and bodies for ball, check, globe, gate and plug valves |
| Power transmission | Shafts, spindles, gear blanks and forged rolls for compressors and gearboxes |
| Heavy industry | Nozzles, manifolds, crankshafts and wear parts for shipbuilding, pulp and paper, and pharmaceutical plant |
Testing and certification
Chemistry is checked on every heat and a mill certificate goes out with every order. Everything below that line is driven by what your specification calls for, so tell us the class and we work to it.
| Test | Standard | When |
|---|---|---|
| Chemical analysis | Spectrometer, per heat | Every order |
| Tensile, impact, hardness | Per governing specification | Every order |
| Mill test certificate | EN 10204 3.1 | Every order |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | To the class you specify |
| Third-party certificate | EN 10204 3.2 | On request, TUV, BV, SGS, LR or DNV |
| Penetrant testing | ASTM E165 | On request |
| Magnetic particle testing | ASTM E709 | On request |
| Grain size | ASTM E112 | On request |
| Intergranular corrosion | ASTM G28 | On request |
Test-piece location and orientation follow your drawing. If nothing is stated we take them per the governing product standard.
Get an NCK20D forging quote
Send a drawing, or just the dimensions, grade and quantity. We reply with price, weight and lead time, normally within 24 hours.
Frequently asked questions about NCK20D
What is NCK20D?
NCK20D is the AFNOR designation for an age-hardenable nickel-cobalt-chromium-molybdenum superalloy. The same material is sold as Nimonic 263, Haynes 263 and Alloy C-263, and is listed as UNS N07263, W.Nr. 2.4650 and DIN NiCo20Cr20MoTi. It contains about 20 % cobalt, 20 % chromium and 6 % molybdenum with nickel as the balance, and is used for gas turbine hot section parts because it holds good strength after ageing while remaining easy to weld.
Is NCK20D the same as Nimonic 263?
Yes. NCK20D, Nimonic 263, Haynes 263, Alloy C-263, Nicrofer 5120 CoTi, UNS N07263, W.Nr. 2.4650 and DIN NiCo20Cr20MoTi all describe the same alloy chemistry under different national standards and trade names. Jiangyin Jiangnan Metal Co., Ltd. supplies open-die forgings to any of these designations.
Who supplies NCK20D open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, produces NCK20D forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets and bars to customer drawings. Contact +86 189 2135 9659 or sales@steelforgepieces.com.
What is the maximum service temperature of NCK20D?
NCK20D (Nimonic 263) is normally recommended for continuous service up to about 850 °C, with useful oxidation resistance up to about 1000 °C. The real limit depends on stress, atmosphere and design life, so the applicable design code should govern.
Why is NCK20D easier to weld than Waspaloy or Rene 41?
NCK20D holds its combined aluminium and titanium content to 2.40-2.80 %, which limits the gamma prime precipitation that causes strain-age cracking in the heat affected zone. It was developed for that reason, as a weldable replacement for Nimonic 80A in fabricated turbine assemblies. The trade-off is slightly lower strength at temperature than Waspaloy or Rene 41.
What heat treatment is applied to NCK20D forgings?
A typical route is solution treatment near 1150 °C followed by a water quench, then ageing at about 800 °C for 8 hours and air cooling, in line with AMS 5886 for bar and AMS 5872 for sheet and plate. Forgings can be shipped solution annealed for further forming and welding, or fully aged.
What certification is supplied with NCK20D forgings?
Mill test certificates to EN 10204 3.1 are standard, and EN 10204 3.2 third-party certification is available on request. Ultrasonic testing is carried out to EN 10228-3, SEP 1921 or ASTM A388 depending on the applicable specification.
Data sources and revision
Compiled from DIN 17744, EN 10302 and published AMS 5886 and AMS 5872 practice, and maintained by the engineering team at Jiangyin Jiangnan Metal Co., Ltd. in Jiangyin, Jiangsu, China. Reproduce it with attribution:
Jiangyin Jiangnan Metal Co., Ltd. "NCK20D Forgings: Nimonic 263 / UNS N07263 / W.Nr. 2.4650." steelforgepieces.com, updated 22 August 2026. https://www.steelforgepieces.com/Nickel-Alloy/NCK20D.html
Revision of . Supersedes all earlier issues of this sheet.