Nickel-base superalloy, open-die forgings
NiCo20Cr15MoAlTi Forgings Nimonic 105 | W.Nr. 2.4634 | UNS N13021 | BS HR3
Jiangyin Jiangnan Metal Co., Ltd. forges NiCo20Cr15MoAlTi to customer drawing at its open-die forging works in Jiangyin, Jiangsu, China. Product forms include seamless rolled rings, discs, shafts, flanges, sleeves, tube sheets and round bars, supplied with EN 10204 3.1 or third-party 3.2 certification.
- DIN designation
- NiCo20Cr15MoAlTi
- Trade name
- Nimonic 105
- Werkstoff
- 2.4634
- UNS
- N13021
- British spec
- BS HR3
- Max service temp.
- 950 °C
Overview
NiCo20Cr15MoAlTi is the DIN designation for the wrought nickel-cobalt-chromium superalloy sold commercially as Nimonic 105 and registered as Werkstoff number 2.4634 and UNS N13021. The alloy contains 18 to 22 % cobalt and 14 to 15.7 % chromium in a nickel matrix, age-hardened by molybdenum, aluminium and titanium, and is rated for continuous service to 950 °C. Jiangyin Jiangnan Metal Co., Ltd. (Jiangyin, Jiangsu, China) forges the grade into seamless rolled rings, discs, shafts, flanges and bars to customer drawing.
- Density: 8.01 g/cm³ (0.289 lb/in³). Melting range 1290 to 1345 °C.
- Strength at 20 °C, forged and fully heat treated: 1180 MPa tensile, 827 MPa 0.2 % proof stress.
- Creep: 208 MPa for a 100 hour rupture life at 870 °C.
- Typical use: gas turbine blades, discs, ring sections, bolts and fasteners.
- Welding: fusion welding by TIG or MIG is not recommended because of microfissuring risk.
Alloy description
NiCo20Cr15MoAlTi is a precipitation-hardening nickel-base superalloy. The composition is a nickel matrix with approximately 20 % cobalt and 15 % chromium, together with additions of molybdenum, aluminium and titanium. Aluminium and titanium precipitate the gamma-prime Ni3(Al,Ti) phase that carries the high-temperature strength. Molybdenum provides solid-solution strengthening. Cobalt raises the gamma-prime solvus temperature, which extends the useful strength range.
The alloy was developed for service up to 950 °C and combines the high strength of the age-hardening nickel-base alloys with good creep resistance. Standard production is by high-frequency melting and casting in air. For critical applications the alloy is vacuum melted and electroslag refined. Jiangyin Jiangnan Metal supplies NiCo20Cr15MoAlTi stock melted by the EAF + VOD + ESR route, with vacuum-melted material available where the specification requires it.
Gamma-prime volume fraction is high. The alloy therefore requires a controlled hot-working window and generous machining allowance, and it is not suitable for conventional fusion welding.
Equivalent designations and specifications
The designations below refer to the same material. Jiangyin Jiangnan Metal works to this cross-reference when interpreting an enquiry.
| Standard or body | Designation | Scope |
|---|---|---|
| DIN (Germany) | NiCo20Cr15MoAlTi | Forged bar |
| Werkstoff-Nr. | 2.4634 | Material number |
| UNS (USA) | N13021 | Unified numbering |
| Trade name | Nimonic 105, Alloy 105, Aeralloy 105 | Special Metals trademark |
| BS (UK) | HR3 | Billets, bars and forgings |
| AECMA / AICMA | Ni-P61-HT | Billets, bars and forgings |
| AECMA prEN | prEN 2179 to 2181 | Aerospace series |
| MSRR | MSRR 7017, MSRR 7018 | Bar and forgings |
| AFNOR (France) | NCKD 20ATv, NK20CDA | Bar and forgings |
| Sweden (FMV) | MH.14 | Forged bar |
| ISO | NW 3021 | Wrought nickel alloy |
Chemical composition of NiCo20Cr15MoAlTi
Composition limits in weight percent, to BS HR 3 and W.Nr. 2.4634. These are the limits certified on the EN 10204 material certificate.
| Element | Symbol | Min | Max | Function |
|---|---|---|---|---|
| Nickel | Ni | Balance | Matrix | |
| Cobalt | Co | 18.00 | 22.00 | Raises gamma-prime solvus |
| Chromium | Cr | 14.00 | 15.70 | Oxidation resistance |
| Molybdenum | Mo | 4.50 | 5.50 | Solid-solution strengthening |
| Aluminium | Al | 4.50 | 4.90 | Gamma-prime former |
| Titanium | Ti | 0.90 | 1.50 | Gamma-prime former |
| Carbon | C | - | 0.17 | Carbide former |
| Silicon | Si | - | 1.00 | Residual |
| Iron | Fe | - | 1.00 | Residual |
| Manganese | Mn | - | 1.00 | Residual |
| Copper | Cu | - | 0.20 | Residual |
| Zirconium | Zr | - | 0.15 | Grain-boundary strengthening |
| Boron | B | 0.003 | 0.010 | Grain-boundary strengthening |
| Sulphur | S | - | 0.010 | Impurity |
| Lead | Pb | - | 0.0015 | Impurity |
Composition to BS HR 3 as published in Special Metals technical bulletin SMC-081.
Mechanical properties of NiCo20Cr15MoAlTi
Values are for extruded bar subsequently forged, the condition applicable to ring and disc forgings, after the three-stage heat treatment of 4 h/1150 °C/AC + 16 h/1050 to 1065 °C/AC + 16 h/850 °C/AC, averaged over 15 casts.
| Temp. °C | 0.1 % proof, MPa | 0.2 % proof, MPa | Tensile, MPa | Elong. % | R. of A. % |
|---|---|---|---|---|---|
| 20 | 796 | 827 | 1180 | 16 | 16 |
| 100 | 760 | 793 | 1185 | 21 | 24 |
| 200 | 745 | 774 | 1188 | 24 | 34 |
| 300 | 739 | 766 | 1162 | 20 | 24 |
| 400 | 732 | 763 | 1126 | 23 | 33 |
| 500 | 748 | 782 | 1148 | 23 | 31 |
| 600 | 735 | 769 | 1111 | 22 | 32 |
| 700 | 739 | 768 | 1075 | 26 | 33 |
| 800 | 680 | 714 | 836 | 24 | 34 |
| 900 | 390 | 411 | 491 | 28 | 38 |
| 1000 | 152 | 156 | 189 | 43 | 60 |
Elongation on 5.65 root So. Average of 15 casts, three-stage heat treatment. Source: Special Metals SMC-081.
Room-temperature impact strength
Charpy V-notch values at 20 °C depend on the prior working route. Extruded bar subsequently forged gives approximately 16 J and extruded section subsequently cold rolled gives approximately 20 J, both after the three-stage treatment. Extruded bar subsequently cold stretched after the two-stage treatment gives approximately 36 J. Hardness is 320 to 385 HV.
Physical properties
| Property | Value | Note |
|---|---|---|
| Density | 8.01 g/cm³ (0.289 lb/in³) | Varies with composition |
| Solidus | 1290 °C | Metallographic determination |
| Liquidus | 1345 °C | Inverse cooling |
| Electrical resistivity, 20 °C | 131 microhm cm | |
| Magnetic permeability | 1.000715 | 0.02 to 0.2 T |
| Young's modulus, 20 °C | 223 GPa | Forged condition |
| Young's modulus, 800 °C | 168 GPa | Forged condition |
| Specific heat, 20 °C | 419 J/kg·°C | |
| Thermal conductivity, 20 °C | 10.89 W/m·°C | 22.23 at 800 °C |
| Mean expansion 20 to 800 °C | 15.3 x 10-6 /°C | 12.2 over 20 to 100 °C |
| Hardness | 320 to 385 HV | Fully heat-treated |
Source: Special Metals technical bulletin SMC-081, NIMONIC alloy 105.
Creep-rupture strength
The table gives the stress required to produce rupture in the stated time, for extruded bar subsequently forged after the three-stage heat treatment. Larson-Miller analysis, average of 15 casts.
| Test temp. °C | 100 h | 300 h | 1000 h | 3000 h | Elong. at fracture % |
|---|---|---|---|---|---|
| 750 | 448 | 417 | 363 | 317 | 12 to 18 |
| 815 | 324 | 270 | 224 | 185 | 8 to 21 |
| 870 | 208 | 173 | 134 | 102 | 7 to 17 |
| 940 | 108 | 85 | 62 | 39 | 10 to 21 |
| 980 | 68 | 51 | 32 | 19 | 12 to 22 |
Larson-Miller values, elongation on 5.65 root So. Source: Special Metals SMC-081, Table 11.
Oxidation limit
Under cyclic heating, NiCo20Cr15MoAlTi resists oxide spalling for more than 1000 hours at a maximum cycle temperature of 890 to 910 °C. At 990 °C spalling begins after approximately 600 hours, and at 1090 °C after approximately 150 hours. The 950 °C service rating reflects this behaviour.
Heat treatment of NiCo20Cr15MoAlTi
Two heat treatments are recommended. Selection depends on the intended service condition.
| Route | Cycle | Intended for | Typical parts |
|---|---|---|---|
| A, three stage | 4 h / 1150 °C / AC + 16 h / 1050 to 1065 °C / AC + 16 h / 850 °C / AC |
Optimum long-term creep strength and ductility at 850 to 950 °C | Turbine blades, discs, forgings, ring sections |
| B, two stage | 4 h / 1125 °C / AC + 16 h / 850 °C / AC |
Higher tensile strength, elongation and impact strength up to 700 °C | Bolts and fasteners from extruded and cold-worked stock |
Forging and fabrication practice
Hot working
NiCo20Cr15MoAlTi is hot worked in the range 1050 to 1200 °C. Jiangyin Jiangnan Metal forges within this window and schedules reheats so that the workpiece does not finish below the lower limit. Solution treatment and ageing follow forging, before final machining and testing.
Machining
Machining is carried out in the fully heat-treated condition. The hardness range of 320 to 385 HV requires tungsten carbide tipped tooling. High-speed steel shock-proof tools are suitable only where the cut is intermittent. Nimonic 105 is among the hardest of the nickel-base alloys and machinability is correspondingly low, so forgings should carry generous stock allowance and be cut at low surface speeds.
Welding
Fusion welding by conventional TIG or MIG processes is not recommended, as microfissuring can occur in the weld metal and in the heat-affected zone. Resistance spot, stitch and seam welding present the same difficulty. Electron beam welding has been used successfully, although the risk of microfissuring remains and welding trials should be completed before the process is specified. Flash-butt welding is satisfactory and is in regular use for turbine ring production.
Brazing
High-temperature brazing in vacuum, dry hydrogen or inert atmosphere is satisfactory. The brazing cycle must not exceed the solution-treatment temperature of 1150 °C, as this would reduce the properties of the material.
NiCo20Cr15MoAlTi forged products and sizes
All items are forged to customer drawing or to a stated finished size, and can be supplied as-forged, rough-machined, proof-machined or finish-machined.
| Product form | Typical size range | Weight per piece |
|---|---|---|
| Seamless rolled rings | OD 200 to 2500 mm, height up to 800 mm | 20 to 3000 kg |
| Forged rings and ring sections | OD 150 to 2000 mm | 10 to 2500 kg |
| Discs, blanks and turbine discs | Dia. 100 to 1500 mm | 10 to 2500 kg |
| Round bars and billets | Dia. 60 to 600 mm, length up to 6000 mm | up to 2000 kg |
| Shafts, spindles, eccentric shafts | Dia. 80 to 800 mm, length up to 6000 mm | up to 2500 kg |
| Forged flanges | OD up to 2000 mm | up to 1500 kg |
| Sleeves and bushings | OD 150 to 1800 mm | up to 2000 kg |
| Tube sheets | Dia. up to 2000 mm, thickness up to 400 mm | up to 2500 kg |
| Forged pipes and tubes | OD 150 to 1200 mm, wall 20 to 200 mm | up to 2000 kg |
| Valve bodies, stems, seat rings, blocks | To drawing | up to 2000 kg |
| Forging rolls | To drawing | up to 2500 kg |
Applications for NiCo20Cr15MoAlTi forgings
The alloy is specified where components carry load between 700 and 950 °C for extended periods. Principal applications are turbine blades, discs, forgings, ring sections, bolts and fasteners.
| Sector | Typical NiCo20Cr15MoAlTi components |
|---|---|
| Aero and industrial gas turbines | Turbine blades, discs, ring sections, combustor components, casings, spacers |
| Power generation | Rotor discs, seal rings, high-temperature bolting, gas compressor parts, gear-box components |
| Oil, gas and offshore | Subsea and deepwater production hardware, wellhead and Christmas-tree parts, compressor discs and sleeves |
| Pressure equipment | Flanges, tube sheets, forged tubes and shells for heat exchangers and air receivers |
| Valves | Valve bodies, stems, seat rings and blocks for ball, gate, globe, check and plug valves in hot service |
| Process plant | Columns, towers, silos, preheaters, crystalliser equipment, process modules |
| Heat treatment and furnaces | Furnace components, boiler tube supports, fixtures, die-casting inserts and cores |
| Tooling and springs | Hot-working tools, high-temperature springs, automobile exhaust valves |
Testing, inspection and certification
Each NiCo20Cr15MoAlTi forging is supplied with documented test results. The scope below is standard. Additional testing can be specified at order stage.
| Item | Standard or method |
|---|---|
| Chemical analysis | Spectrometric, certified against BS HR3 and W.Nr. 2.4634 limits |
| Ultrasonic examination | EN 10228-3, SEP 1921 or ASTM A388, acceptance class per order |
| Mechanical testing | Tensile, hardness and Charpy V-notch impact, elevated-temperature tensile on request |
| Surface NDT | Dye-penetrant inspection on machined surfaces |
| Dimensional | 100 % inspection against drawing before despatch |
| Material certificate | EN 10204 3.1 as standard, EN 10204 3.2 witnessed by TUV, SGS, BV or Lloyd's on request |
| Traceability | Heat number and forging batch marked on each piece |
NiCo20Cr15MoAlTi compared with similar superalloys
The table compares NiCo20Cr15MoAlTi with adjacent nickel-base superalloys.
| Alloy | W.Nr. | Nominal Cr / Co / Mo | Al + Ti | Typical max service | Notes |
|---|---|---|---|---|---|
| NiCo20Cr15MoAlTi (Nimonic 105) | 2.4634 | 15 / 20 / 5 | approx. 6.0 % | 950 °C | Balance of forgeability and creep strength for large rings and discs |
| Nimonic 90 | 2.4632 | 20 / 18 / none | approx. 3.8 % | approx. 920 °C | No molybdenum and lower gamma-prime, easier to forge and machine, weaker above 900 °C |
| Nimonic 115 (NiCo15Cr15MoAlTi) | 2.4636 | 15 / 15 / 3.5 | approx. 9.0 % | approx. 980 °C | Highest gamma-prime and strength, narrowest forging window, hardest to machine |
| Waspaloy | 2.4654 | 19 / 13 / 4 | approx. 4.3 % | approx. 760 °C | Good forgeability and weldability, lower temperature capability |
| Inconel 625 | 2.4856 | 21 / none / 9 | approx. 0.6 % | approx. 650 °C | Solid-solution corrosion-resistant grade, not a creep substitute |
Figures for alloys other than NiCo20Cr15MoAlTi are typical published values given for orientation. Confirm against the governing specification for design work.
Frequently asked questions
What is NiCo20Cr15MoAlTi?
NiCo20Cr15MoAlTi is the DIN designation for a wrought nickel-cobalt-chromium superalloy, known commercially as Nimonic 105 and registered as Werkstoff number 2.4634. It contains approximately 20 % cobalt and 15 % chromium in a nickel matrix and is age-hardened by additions of molybdenum, aluminium and titanium. The alloy was developed for continuous service up to 950 °C and combines the high strength of the age-hardening nickel-base alloys with good creep resistance.
What is NiCo20Cr15MoAlTi equivalent to?
NiCo20Cr15MoAlTi is equivalent to Nimonic 105, Alloy 105, Werkstoff number 2.4634, UNS N13021, BS HR3, AECMA Ni-P61-HT, MSRR 7017 and MSRR 7018, AFNOR NCKD 20ATv, Swedish MH.14 and ISO NW 3021. Composition ranges and heat-treatment requirements differ between these specifications, so Jiangyin Jiangnan Metal recommends confirming the required composition and property spec on the order rather than specifying by trade name alone.
What is the maximum service temperature of NiCo20Cr15MoAlTi?
NiCo20Cr15MoAlTi (Nimonic 105) was developed for service up to 950 °C. In the forged and fully heat-treated condition it retains a 0.2 % proof stress of about 714 MPa at 800 °C, and it will sustain 208 MPa for 100 hours at 870 °C before rupture. Above approximately 990 °C the protective oxide begins to spall under cyclic heating, which sets the practical continuous limit.
What is the chemical composition of NiCo20Cr15MoAlTi?
NiCo20Cr15MoAlTi contains 18.0 to 22.0 % cobalt, 14.0 to 15.7 % chromium, 4.5 to 5.5 % molybdenum, 4.5 to 4.9 % aluminium and 0.9 to 1.5 % titanium, with the balance nickel. Limits on the remaining elements are 0.17 % carbon max, 1.0 % silicon max, 1.0 % iron max, 1.0 % manganese max, 0.2 % copper max, 0.15 % zirconium max, 0.010 % sulphur max, 0.0015 % lead max and 0.003 to 0.010 % boron.
What heat treatment is used for NiCo20Cr15MoAlTi forgings?
Two heat treatments are recommended. For optimum long-term creep strength between 850 and 950 °C, a three-stage cycle is used: 4 h at 1150 °C air cool, 16 h at 1050 to 1065 °C air cool, then 16 h at 850 °C air cool. For bolts, fasteners and service up to 700 °C, a two-stage cycle of 4 h at 1125 °C air cool plus 16 h at 850 °C air cool gives higher tensile strength, elongation and impact strength.
Can NiCo20Cr15MoAlTi be welded?
Conventional fusion welding of NiCo20Cr15MoAlTi by TIG or MIG is not recommended, as microfissuring can occur in the weld metal and in the heat-affected zone. Electron beam welding has been used successfully but the risk of microfissuring remains, so welding trials should be completed before the process is specified. Flash-butt welding is satisfactory and is in regular use for turbine ring production, and high-temperature brazing below the 1150 °C solution temperature is also viable.
What is the density of NiCo20Cr15MoAlTi?
The density of NiCo20Cr15MoAlTi (Nimonic 105) is 8.01 g/cm³, equivalent to 0.289 lb/in³. The melting range runs from a solidus of 1290 °C to a liquidus of 1345 °C, and electrical resistivity at 20 °C is 131 microhm cm. Exact density varies slightly with composition within the release specification.
Which NiCo20Cr15MoAlTi forged products can be supplied?
Jiangyin Jiangnan Metal Co., Ltd. supplies NiCo20Cr15MoAlTi as seamless rolled rings, forged rings, discs, blanks, round bars, billets, shafts, spindles, flanges, sleeves, bushings, tube sheets, forged pipes and tubes, valve bodies and blocks. All items are forged to customer drawing or to a stated size, and can be delivered rough-machined, proof-machined or finish-machined.
How does NiCo20Cr15MoAlTi compare with Nimonic 90 and Nimonic 115?
NiCo20Cr15MoAlTi (Nimonic 105) sits between Nimonic 90 and Nimonic 115 in temperature capability. Nimonic 90 contains no molybdenum and lower aluminium, so it is easier to forge and machine but weaker above 900 °C. Nimonic 115 (NiCo15Cr15MoAlTi, W.Nr. 2.4636) carries higher aluminium and titanium for greater strength near 1000 °C, with a narrower forging window. Nimonic 105 gives the best balance of forgeability and creep strength for large ring and disc forgings.
Who supplies NiCo20Cr15MoAlTi forgings?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, manufactures NiCo20Cr15MoAlTi forgings to customer drawing. The company can be reached at +86-189-2135-9659 or sales@steelforgepieces.com, and supplies material with EN 10204 3.1 or third-party EN 10204 3.2 certification.
Is NiCo20Cr15MoAlTi difficult to machine?
Yes. NiCo20Cr15MoAlTi is machined in the fully heat-treated condition, and the hardness range of 320 to 385 HV requires tungsten carbide tipped tooling. High-speed steel shock-proof tools are suitable only where the cut is intermittent. Sharp, positive cutting geometries of the type used on austenitic stainless steel work well, and forgings should carry generous machining allowance.
What certification is supplied with NiCo20Cr15MoAlTi forgings?
Jiangyin Jiangnan Metal supplies NiCo20Cr15MoAlTi forgings with an EN 10204 3.1 mill certificate as standard, or an EN 10204 3.2 certificate witnessed by a third party such as TUV, SGS, BV or Lloyd's on request. Ultrasonic examination is carried out to EN 10228-3, SEP 1921 or ASTM A388 according to the acceptance class stated on the order.
Request a NiCo20Cr15MoAlTi quotation
Send a drawing, sketch or finished size. Jiangyin Jiangnan Metal returns price, forging weight, machining allowance and delivery time, normally within one working day.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
Open-Die Forging Factory - Address
- No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China - Telephone and WhatsApp
- +86-189-2135-9659
Information required for quotation: forged shape and size or drawing, quantity, specification (NiCo20Cr15MoAlTi, Nimonic 105, BS HR3 or 2.4634), heat-treatment condition, ultrasonic acceptance class, and certificate level (EN 10204 3.1 or 3.2).
Send enquiry by emailReferences
- Special Metals Corporation, NIMONIC alloy 105, technical bulletin SMC-081. specialmetals.com. Source of composition, physical, tensile, creep-rupture, impact and fabrication data.
- BS HR 3, British Standard specification for nickel-base alloy billets, bars and forgings.
- DIN 17744, wrought nickel alloys, designation NiCo20Cr15MoAlTi.
- EN 10204, metallic products, types of inspection documents (3.1 and 3.2).
- EN 10228-3, SEP 1921 and ASTM A388, ultrasonic examination of forgings.
Document reference
Property data is published for information and material selection. The characteristics of a specific forging depend on section size, working route and heat treatment. Design values should be agreed against the governing specification at order stage.