Nickel alloy · Open-die forgings · Technical datasheet
2.4610 / Alloy C-4 / UNS N06455 Forging Parts NiMo16Cr16Ti · Forged rings · Seamless rolled rings · Flanges · Shafts · Discs · Tube sheets · Bars
NiMo16Cr16Ti
Alloy C-4
DIN 17744 · VdTÜV 424
Haynes International, Inc.
Jiangyin Jiangnan Metal Co., Ltd. is an independent open-die forging factory in Jiangyin, Jiangsu, China. We produce 2.4610 / UNS N06455 / NiMo16Cr16Ti, the generic low-carbon nickel-molybdenum-chromium chemistry sold under the Hastelloy® C-4 trademark, as forged rings, seamless rolled rings, flanges, shafts, discs, tube sheets, sleeves, bushings, nozzles and bars. All 2.4610 forgings are supplied solution annealed at 1066 °C with rapid water quench, ultrasonically tested to ASTM A388 or EN 10228-3, and certified to EN 10204 3.1, or 3.2 with third-party witness on request. Our envelope in this grade is rolled rings to 2,000 mm OD, discs to Ø 1,500 mm, shafts to 6 m and single-piece weights to 5,000 kg.
Hastelloy® is a registered trademark of Haynes International, Inc.; Nicrofer® of VDM Metals; BÖHLER of voestalpine. Material made by those companies and sold under those brand names is theirs. Material we produce is correctly described as UNS N06455 / W.-Nr. 2.4610 / NiMo16Cr16Ti, the same generic chemistry, manufactured independently by Jiangyin Jiangnan Metal Co., Ltd. We are not affiliated with, sponsored by, or endorsed by any trademark holder named on this page.
What is 2.4610 (Alloy C-4 / UNS N06455)?
2.4610 is the EN / DIN material number for NiMo16Cr16Ti, a low-carbon austenitic nickel-molybdenum-chromium alloy also designated UNS N06455 and known commercially as Alloy C-4. It contains approximately 65 % nickel, 14.0-18.0 % chromium and 14.0-17.0 % molybdenum, with carbon restricted to 0.015 % max, silicon to 0.08 % max, iron to 3.0 % max, and a titanium addition up to 0.70 % as a carbide stabiliser.
The property that distinguishes 2.4610 within the C family is thermal stability. The combination of very low carbon and silicon, the absence of tungsten, low iron, and the titanium stabiliser suppresses the precipitation of grain-boundary carbides and µ phase across the whole 650-1040 °C (1200-1900 °F) band. In practice that means a 2.4610 forging that has been welded, stress-relieved or held at elevated temperature does not sensitise: it keeps its ductility and its resistance to intergranular attack, and welded joints show no knife-line attack in the heat-affected zone. Hastelloy C-276 and Alloy 625 both precipitate second phases in that same temperature band.
The second defining property is corrosion resistance in reducing media. The high molybdenum content handles hydrochloric, sulphuric, phosphoric, formic and acetic acids; the chromium content extends useful service into moderately oxidising conditions; and the ~65 % nickel base makes the alloy practically immune to chloride stress corrosion cracking, even in hot chloride solutions where 304 and 316L crack within hours. Its pitting resistance equivalent number (PREN = Cr + 3.3 × Mo) is around 67, roughly two and a half times that of 316L.
2.4610 is solid-solution strengthened and not age hardenable. It is supplied in one condition only: solution annealed and rapidly quenched. Further hardening is possible only by cold work. Any ageing or precipitation-hardening cycle applied to this grade is a specification error: it will not raise strength usefully and it will damage corrosion resistance.
Ni-Mo-Cr, austenitic
Solid-solution strengthened, single-phase FCC, non-magnetic (µᵣ ≈ 1.0).
Thermal stability
Resists carbide and µ-phase precipitation 650-1040 °C. No sensitisation, no knife-line attack.
Solution annealed only
1066 °C, hold 10-30 min, water quench. Not age hardenable.
Specify 2.4610 / UNS N06455 when your part will be welded, thermally cycled, or held at temperature in an aggressive reducing acid or chloride environment and you cannot tolerate sensitisation. If the duty is strongly oxidising or a mixed-acid stream and there is no high-temperature exposure, C-276 or C-22 is usually the better economic choice. See the side-by-side comparison.
What forged products are available in 2.4610?
Jiangyin Jiangnan Metal manufactures 2.4610 / UNS N06455 by three routes, selected by geometry and quantity. Open-die forging covers shafts, blocks, discs and near-net blanks. It is the dominant route for this grade, because the narrow hot-working window rewards incremental reduction with frequent reheats. Seamless ring rolling produces rolled rings from 200 mm to 2,000 mm outside diameter, the usual route for reactor and heat-exchanger flanges, girth rings and pressure-housing blanks. Upset forging is reserved for short, large-cross-section hubs and tube sheets. Every route ends with the same mandatory step: re-solution annealing at 1066 °C with rapid water quench, because hot working leaves the alloy in a state where corrosion performance is not guaranteed.
- Forged rings
- Seamless rolled rings
- Contoured rolled rings
- Forged flanges
- Forged shafts
- Agitator shafts
- Forged discs
- Forged blocks
- Tube sheets
- Forged sleeves
- Bushings
- Nozzles
- Valve bodies & stems
- Round bars 20-400 mm
- Hollow / trepanned bars
- Near-net-shape forgings
What are the equivalent designations of 2.4610?
Buyers reach this alloy through at least eight different names. All of the designations below describe the same chemistry, and Jiangyin Jiangnan Metal accepts purchase orders under any of them, issuing a multi-designation material test certificate that lists every specification the heat satisfies.
| Body / region | Designation | Notes |
|---|---|---|
| EN / DIN material number | 2.4610 | The primary European reference for this alloy |
| EN chemical designation | NiMo16Cr16Ti | Also written NiMo16Cr17Ti in some older catalogues |
| USA · UNS | N06455 | Unified Numbering System. The safest generic designation for a purchase order |
| USA · common name | Alloy C-4 | Generic industry name, not a trademark |
| ISO | NiMo16Cr16Ti | Matches the EN chemical designation |
| Brand · Haynes International | Hastelloy® C-4 | Trademark We do not sell under this name |
| Brand · VDM Metals | Nicrofer® 6616 hMo | Trademark |
| Brand · voestalpine BÖHLER | BÖHLER L004 | Trademark |
| Matching weld filler | 2.4611 / 2.4612 · ERNiCrMo-7 | AWS A5.14 classification for GTAW / GMAW wire |
Which standard covers which product form?
| Product form | ASTM / ASME | European | Other |
|---|---|---|---|
| Rod & bar | ASTM B574 · ASME SB-574 | DIN 17744 · DIN 17752 | SAE AMS 5772 |
| Forgings | ASTM B564 · ASME SB-564 | DIN 17744 · VdTÜV WB 424 | AFNOR AIR 9165 |
| Plate, sheet & strip | ASTM B575 · ASME SB-575 | DIN 17751 | SAE AMS 5608 |
| Seamless pipe & tube | ASTM B622 · ASME SB-622 | DIN 17751 | n/a |
| Welded pipe & tube | ASTM B619 · B626 | n/a | n/a |
| Fittings | ASTM B366 | n/a | n/a |
| Wire | n/a | DIN 17753 | SAE AMS 5801 |
| Pressure equipment approval | ASME BPVC Sec. II-B | VdTÜV Werkstoffblatt 424 | PED 2014/68/EU |
| Sour service | NACE MR0103 / ISO 17945 | n/a | NACE MR0175 / ISO 15156 |
| Inspection document | n/a | EN 10204 3.1 · 3.2 | n/a |
🔎 Multi-standard designation lookup
Type any name you have on a drawing (2.4610, N06455, C-4, NiMo16Cr16Ti, B574) and see every equivalent.
Start typing to search 30+ designations, brand names and standards.
All matched designations refer to the same chemistry. Jiangyin Jiangnan Metal Co., Ltd. ships UNS N06455 / 2.4610 with a multi-designation material test certificate listing every specification the heat satisfies.
What is the chemical composition of 2.4610?
Per DIN 17744 for NiMo16Cr16Ti (2.4610): carbon 0.015 % max, silicon 0.08 % max, manganese 1.00 % max, phosphorus 0.025 % max, sulphur 0.015 % max, chromium 14.0-18.0 %, molybdenum 14.0-17.0 %, titanium 0.70 % max, iron 3.0 % max, cobalt 2.0 % max, copper 0.50 % max, nickel balance (approximately 65 %).
| Element | Min | Max | Metallurgical role |
|---|---|---|---|
| Nickel (Ni) | balance | ≈ 65 | Austenitic matrix; source of the alloy's immunity to chloride stress corrosion cracking |
| Molybdenum (Mo) | 14.0 | 17.0 | Resistance to reducing acids (HCl, H₂SO₄) and to pitting and crevice attack |
| Chromium (Cr) | 14.0 | 18.0 | Passive film; extends service into oxidising conditions |
| Iron (Fe) | n/a | 3.0 | Held low to suppress precipitation and improve thermal stability |
| Cobalt (Co) | n/a | 2.0 | Residual; restricted for nuclear service (Co-60 activation) |
| Manganese (Mn) | n/a | 1.00 | Deoxidiser and sulphur getter |
| Titanium (Ti) | n/a | 0.70 | Stabiliser. Ties up carbon as TiC, preventing chromium-carbide sensitisation |
| Copper (Cu) | n/a | 0.50 | Residual |
| Phosphorus (P) | n/a | 0.025 | Impurity; segregates to grain boundaries |
| Carbon (C) | n/a | 0.015 | Held very low; the single most important lever on intergranular corrosion resistance |
| Sulphur (S) | n/a | 0.015 | Impurity; degrades hot workability |
| Silicon (Si) | n/a | 0.08 | Held very low to suppress µ-phase formation at 650-1040 °C |
| Tungsten (W) | not present | Deliberately omitted; its absence gives C-4 its thermal stability advantage over C-276 | |
Carbon at 0.015 % max and silicon at 0.08 % max are not incidental limits. They are the design of the alloy. Together with the titanium stabiliser and the absence of tungsten, they are what stop grain-boundary carbides and µ phase from forming during welding or elevated-temperature service. An otherwise-conforming heat with silicon at 0.30 % would still pass a loose specification but would lose most of the thermal-stability advantage you are paying for. Always require the actual analysis on the certificate, not just a conformance statement.
How do DIN 17744, ASTM B574 and VdTÜV 424 differ for 2.4610?
Most supplier pages present a single composition table and imply the standards are identical. They are not. The three references in common use set different limits on the very elements that control this alloy's signature property. VdTÜV Werkstoffblatt 424, the European pressure-equipment sheet, is materially tighter than both DIN 17744 and ASTM B574 on carbon, silicon, phosphorus and sulphur, and narrows the chromium band. A heat produced to VdTÜV 424 limits automatically satisfies the other two.
| Element | DIN 17744 | ASTM B574 / SB-574 | VdTÜV WB 424 | Comment |
|---|---|---|---|---|
| Carbon (C) | 0.015 | 0.015 | 0.009 | VdTÜV is ~40 % tighter; best intergranular performance |
| Silicon (Si) | 0.08 | 0.08 | 0.050 | Tighter Si suppresses µ phase |
| Manganese (Mn) | 1.00 | 1.00 | 1.00 | Identical |
| Phosphorus (P) | 0.025 | 0.040 | 0.020 | ASTM is the most permissive |
| Sulphur (S) | 0.015 | 0.030 | 0.010 | ASTM allows 3× the VdTÜV limit |
| Chromium (Cr) | 14.0-18.0 | 14.0-18.0 | 14.5-17.5 | VdTÜV narrows the band both ways |
| Molybdenum (Mo) | 14.0-17.0 | 14.0-17.0 | 14.0-17.0 | Identical |
| Titanium (Ti) | 0.70 | 0.70 | 0.70 | Identical |
| Iron (Fe) | 3.0 | 3.0 | 3.0 | Identical |
| Cobalt (Co) | 2.0 | 2.0 | 2.0 | Identical |
| Copper (Cu) | 0.50 | not specified | 0.50 | ASTM does not limit Cu |
If your equipment is destined for a European pressure-equipment file, or the service involves any high-temperature exposure or heavy welding, specify VdTÜV Werkstoffblatt 424 limits. A single heat made to those limits satisfies DIN 17744 and ASTM B574 simultaneously, and we will cross-certify all three on one certificate at no extra cost. For general chemical-plant duty with no code requirement, ASTM B574 / ASME SB-574 is the economical default.
What are the mechanical properties of 2.4610?
In the solution-annealed condition at room temperature, ASTM B574 / ASME SB-574 requires a minimum tensile strength of 690 MPa (100 ksi), a minimum 0.2 % proof strength of 276 MPa (40 ksi) and minimum elongation of 40 %. European practice to DIN 17744 and VdTÜV 424 requires Rm ≥ 700 MPa and Rp0.2 ≥ 305 MPa. Typical measured values on forged and annealed product run appreciably higher: around 780 MPa tensile, 360 MPa proof strength and 55 % elongation.
| Property | ASTM B574 min | DIN 17744 / VdTÜV min | Typical (forged + annealed) |
|---|---|---|---|
| Tensile strength Rm | 690 MPa (100 ksi) | 700 MPa | ≈ 780 MPa (113 ksi) |
| Yield strength Rp0.2 | 276 MPa (40 ksi) | 305 MPa | ≈ 360 MPa (52 ksi) |
| Elongation A5 | 40 % | 40 % | ≈ 55 % |
| Reduction of area | not specified | not specified | ≈ 60 % |
| Hardness | n/a | n/a | ≈ 85-95 HRB |
| Modulus of elasticity E | n/a | 211 GPa (30.6 × 10⁶ psi) | |
| Impact toughness (Charpy V, RT) | not mandated | high; fully ductile, no DBTT | |
The gap between the 690 MPa specification minimum and the ~780 MPa typical value is real but it is not a design allowance. Design to the code minimum; use the typical values only for machining-load and handling estimates. For pressure-equipment design, allowable stresses must be taken from ASME BPVC Section II Part D or the applicable European harmonised route, not from a supplier datasheet, including this one. Our certificate reports the actual tested values for your heat.
Behaviour at temperature
2.4610 retains useful strength and full ductility well above the range where austenitic stainless steels begin to creep. Unlike C-276 and Alloy 625, it does not embrittle after long exposure in the 650-1040 °C band. That thermal stability, not raw strength, is the reason it appears in high-temperature chemical service. Because the alloy is solid-solution strengthened and not precipitation hardened, strength falls smoothly with temperature and there is no ageing peak to exploit. Elevated-temperature tensile and design-stress data for a specific heat and section are available with quotation on request.
What are the physical properties of 2.4610?
| Property | Value | Imperial | Note |
|---|---|---|---|
| Density | 8.6 g/cm³ | 0.311 lb/in³ | Used for all forging-weight calculations on this page |
| Melting range | 1335-1400 °C | 2435-2550 °F | Solidus / liquidus |
| Modulus of elasticity | 211 GPa | 30.6 × 10⁶ psi | In tension, 20 °C |
| Specific heat capacity | 408 J/kg·K | 0.097 Btu/lb·°F | 20 °C |
| Thermal conductivity | 10.1 W/m·K | 5.8 Btu/hr·ft·°F | 20 °C; low, as with all Ni-Mo-Cr alloys |
| Electrical resistivity | 1.24 µΩ·m | 1.24 Ω·mm²/m | 20 °C |
| Mean thermal expansion 20-538 °C | 13.3 × 10⁻⁶/K | 7.4 × 10⁻⁶/°F | Relevant to tube-sheet / shell differential growth |
| Mean thermal expansion 20-649 °C | 13.5 × 10⁻⁶/K | 7.5 × 10⁻⁶/°F | |
| Mean thermal expansion 20-760 °C | 14.4 × 10⁻⁶/K | 8.0 × 10⁻⁶/°F | |
| Magnetic permeability µr | ≈ 1.0 | n/a | Non-magnetic, fully austenitic |
| PREN (Cr + 3.3 × Mo) | ≈ 67 | n/a | 316L ≈ 25 · C-276 ≈ 69 · C-22 ≈ 69 |
Low thermal conductivity has two practical consequences you should plan for: heat concentrates at the cutting edge during machining, so coolant and feed discipline matter more than with steel; and heavy sections need longer soak times at the annealing temperature than the equivalent steel section.
Why is 2.4610 the most thermally stable alloy in the C family?
2.4610 / Alloy C-4 resists the precipitation of grain-boundary carbides and µ phase across the entire 650-1040 °C (1200-1900 °F) range. Because it does not sensitise, welded joints show no knife-line attack in the heat-affected zone and no post-weld solution anneal is required for most services. In fabricated equipment that is a decisive practical and cost advantage over C-276 and Alloy 625.
Four chemistry decisions produce this behaviour, and it is worth understanding them because they explain why a "close enough" substitute heat will not perform the same way:
- Carbon capped at 0.015 % (0.009 % under VdTÜV 424)
Below the threshold at which chromium carbides can form in quantity at grain boundaries, which is the mechanism behind sensitisation and intergranular attack.
- Titanium up to 0.70 % as a stabiliser
Titanium has a far stronger affinity for carbon than chromium does, so residual carbon is tied up as TiC rather than as Cr₂₃C₆. The chromium stays in solution, where it is doing corrosion work.
- Silicon capped at 0.08 % and iron at 3.0 %
Silicon and iron both accelerate the formation of µ phase, a brittle intermetallic that embrittles grain boundaries. Holding both low removes the driver.
- Tungsten deliberately omitted
C-276 carries 3-4.5 % tungsten, which raises resistance in some oxidising media but strongly promotes µ-phase precipitation on ageing. C-4 trades that oxidising performance for stability.
No mandatory post-weld solution anneal for most services. That removes a furnace cycle, a distortion risk and a re-inspection from the fabrication route. On a large welded vessel or exchanger that is often the largest single cost difference between C-4 and C-276.
🌡 Thermal-stability & sensitisation risk checker
Enter your service or fabrication temperature and exposure time to see how 2.4610 compares with C-276, C-22 and Alloy 625.
First-pass screening based on published precipitation behaviour of Ni-Cr-Mo alloys. Real behaviour depends on the actual heat chemistry, section size, cooling rate and prior cold work. Final material acceptance requires review by a qualified materials engineer. Jiangyin Jiangnan Metal Co., Ltd. provides this tool for guidance and accepts no liability for application decisions.
How corrosion-resistant is 2.4610?
2.4610 is built for reducing environments, the ones where chromium alone cannot form a stable passive film and molybdenum has to do the work. With 14-17 % Mo it handles hydrochloric, sulphuric, phosphoric, formic and acetic acids, including contaminated streams. The 14-18 % chromium extends useful service into moderately oxidising conditions and into wet chlorine, hypochlorite and chlorine dioxide. The ~65 % nickel base makes the alloy practically immune to chloride stress corrosion cracking.
| Medium | Behaviour | Notes and limits |
|---|---|---|
| Hydrochloric acid (HCl) | Excellent | Resistant across all concentrations at ambient to moderate temperature; corrosion rate rises sharply with temperature and with aeration. Define concentration and temperature before selecting. |
| Sulphuric acid (H₂SO₄) | Very good | Good across dilute to intermediate concentrations; performance falls in hot concentrated acid. Contamination with oxidising ions (Fe³⁺, Cu²⁺) generally improves behaviour. |
| Phosphoric acid (H₃PO₄) | Excellent | Including wet-process acid containing fluorides and chlorides |
| Formic & acetic acid | Excellent | Standard material of construction for acetic-acid and pesticide plant |
| Nitric acid (HNO₃) | Moderate | Notably resistant to intergranular attack in boiling nitric, but strong oxidising nitric duty favours higher-chromium grades such as Alloy 690 or 33 |
| Wet chlorine, hypochlorite, ClO₂ | Very good | Bleach plant and disinfection service |
| Oxidising chlorides (FeCl₃, CuCl₂) | Very good | High PREN ≈ 67 resists pitting and crevice attack |
| Seawater & brines | Excellent | No chloride SCC; resists crevice attack under deposits and gaskets |
| Caustic (NaOH) | Very good | Apply the 705 °C stress-relief described below before caustic service |
| Flue-gas desulphurisation | Excellent | Acid chloride condensate duty; a core application for this grade |
| Sour service (H₂S) | Qualified | Covered by NACE MR0175 / ISO 15156 and MR0103 / ISO 17945; confirm hardness and cold-work limits per the applicable annex |
| Hot concentrated oxidising acids | Not preferred | Use higher-chromium grades: C-22, Alloy 59 or Alloy 690 |
Every entry above is a first-pass screen, not a service guarantee. Corrosion rate in real plant is controlled by concentration, temperature, aeration, velocity, contaminants and crevice geometry acting together, and a change in any one of them can move a medium from "excellent" to "unacceptable". For any duty outside routine practice, run a coupon test in the actual process stream or commission a corrosion engineer. We can supply test coupons from the same heat as your forging.
⚗ Acid- and chloride-service screening tool
Pick a medium, concentration and temperature for a first-pass verdict on 2.4610, plus the alternative grade to consider.
Screening logic follows published isocorrosion behaviour for Ni-Cr-Mo alloys. It is not a substitute for coupon testing in the actual stream. Jiangyin Jiangnan Metal Co., Ltd. provides this tool for guidance and accepts no liability for application decisions.
2.4610 vs C-276 vs C-22 vs Alloy 59 vs 625 vs 316L
Each of these alloys is the right answer to a different question. In short: C-4 wins on thermal stability, C-276 on mixed-acid breadth, C-22 and 59 on oxidising duty, 625 on strength and cost, 316L on price wherever it survives.
| Property | 2.4610 · C-4 | C-276 | C-22 | Alloy 59 | Alloy 625 | 316L |
|---|---|---|---|---|---|---|
| UNS | N06455 | N10276 | N06022 | N06059 | N06625 | S31603 |
| W.-Nr. | 2.4610 | 2.4819 | 2.4602 | 2.4605 | 2.4856 | 1.4404 |
| Cr % | 14-18 | 14.5-16.5 | 20-22.5 | 22-24 | 20-23 | 16-18 |
| Mo % | 14-17 | 15-17 | 12.5-14.5 | 15-16.5 | 8-10 | 2-3 |
| W % | none | 3-4.5 | 2.5-3.5 | none | none | none |
| PREN ≈ | 67 | 69 | 69 | 76 | 51 | 25 |
| Thermal stability | Best in class | Moderate | Good | Good | Moderate | Sensitises |
| Reducing acids | Excellent | Excellent | Very good | Excellent | Good | Poor |
| Oxidising acids | Moderate | Moderate | Excellent | Excellent | Good | Fair |
| Chloride SCC | Immune | Immune | Immune | Immune | Immune | Susceptible |
| Rm min (MPa) | 690 | 690 | 690 | 690 | 827 | 485 |
| Density (g/cm³) | 8.6 | 8.89 | 8.69 | 8.6 | 8.44 | 8.0 |
| PWHT after welding | Normally none | Often required | Usually none | Usually none | Often required | Usually none |
| Relative alloy cost | ≈ 9× | ≈ 10× | ≈ 10× | ≈ 12× | ≈ 7× | 1× (baseline) |
| Choose it when | Welded or thermally cycled reducing-acid duty | Broadest mixed-acid coverage | Oxidising + reducing, upset-tolerant | Most aggressive mixed service | Strength + moderate corrosion at lower cost | Anywhere it survives |
Relative cost figures are order-of-magnitude alloy-price indices against 316L, indicative only, and move with the LME nickel and ferro-molybdenum markets. We quote index-linked pricing on request. Related grade pages: C-276 · C-22 · C-2000 · Alloy 59 · Inconel 625.
How do you forge, heat treat, weld and machine 2.4610?
Hot forging
Hot forging of 2.4610 starts at 1177 °C (2150 °F) and must finish above 954 °C (1750 °F). The window is narrow, roughly 220 °C wide, and the alloy is markedly more sensitive to strain and strain rate than austenitic stainless steel. Moderate reductions with frequent reheating give the best result.
Practical consequences on the hammer and press: plan more reheats than you would for a steel forging of the same size, keep the die contact time short so the surface does not chill below 954 °C, and avoid heavy single blows that concentrate strain. Forging below the finish temperature invites cracking. After the last operation the part must be re-solution annealed. Hot working alone does not leave the alloy in a condition where corrosion performance is guaranteed.
Solution annealing: the only heat treatment this alloy gets
| Treatment | Temperature | Hold | Cooling & purpose |
|---|---|---|---|
| Solution anneal (standard) | 1066 °C (1950 °F) | 10-30 min | Water quench. Rapid air cooling acceptable only below 10 mm section. Restores full corrosion resistance and ductility. |
| Solution anneal (code / PWHT route) | 1065-1080 °C | per thickness | Rapid water quench. Used where a design code requires post-weld restoration of base-metal properties. |
| Stress relief for caustic service | 705 °C (1300 °F) | ≥ 30 min per 25 mm | Applied before caustic duty only |
| Ageing / precipitation hardening | Not applicable | Do not specify. 2.4610 is not age hardenable. Ageing gains no useful strength and degrades corrosion resistance. | |
| Re-anneal after cold work | 1066 °C | 10-30 min | Mandatory when outer-fibre elongation reaches 7 % or more |
Purchase specifications for 2.4610 sometimes carry over an "aged" or "solution treated and aged" clause from a precipitation-hardening grade. 2.4610 has no ageing treatment. It is supplied solution annealed and water quenched, and it is strengthened further only by cold work. If your drawing calls for ageing on this grade, that clause needs to be removed before the order can be produced correctly.
Welding
2.4610 welds readily by GTAW and GMAW using techniques similar to 300-series stainless steel, with matching filler (W.-Nr. 2.4611 / 2.4612, AWS A5.14 ERNiCrMo-7). Keep heat input low, use stringer beads rather than heavy weave, control interpass temperature, and clean rigorously beforehand. Oil, grease, marking crayon and above all sulphur- and chloride-bearing contamination must be removed with a dedicated stainless brush and solvent wipe. Post-weld heat treatment is normally not required, which is the alloy's headline fabrication advantage. The two exceptions are caustic service (705 °C stress relief) and cases where a design code mandates a full solution anneal.
Machining
Machine in the solution-annealed condition. The alloy work hardens faster than austenitic stainless steel, so the governing rule is: never let the tool dwell or rub. Use rigid setups and sharp positive-rake carbide tooling, cut at roughly 15-25 m/min for turning, apply a generous positive feed, and keep the depth of cut below the previously work-hardened layer. Light finishing passes that skim the hardened skin are how tools get destroyed. Flood coolant throughout. Expect roughly one third of the metal-removal rate you would achieve on 316L, and budget tooling accordingly.
🔥 2.4610 forging & solution-annealing recipe generator
Enter section thickness and operation to get a printable cycle for your forge shop and heat-treatment vendor.
Cycles follow published practice for UNS N06455 and scale hold time with section thickness. Always validate with your heat-treatment vendor's furnace survey and confirm properties on test coupons from the same heat.
2.4610 production capability at Jiangyin Jiangnan Metal
Nickel-molybdenum-chromium alloys demand tighter thermal control than steel and a narrower forging window, so our published envelope for 2.4610 is deliberately more conservative than for stainless or carbon-steel forgings. Every figure below is a tested limit for this alloy family.
Process route: raw material to certificate
Equipment and inspection facilities
1 t · 3 t · 5 t · 9 t open-die hammers
Incremental reduction with frequent reheat, the route that suits 2.4610's narrow hot-working window.
Free-forging hydraulic presses
Heavy sections, blocks, discs and long shafts to 6 m.
3 m and 6 m seamless ring mills
Rectangular, contoured and T-section rings; 2.4610 rings to 2,000 mm OD.
Solution furnaces + quench tank
Charted cycles, with rapid transfer to water quench. Transfer speed is critical for this grade's corrosion performance.
Ultrasonic, magnetic particle & penetrant
UT to ASTM A388, EN 10228-3 or SEP 1921. 2.4610 is non-magnetic, so surface NDE uses liquid penetrant, not MT.
Spectrometer · universal testing machine · impact tester · metallographic microscope · hardness testers
Full chemistry, tensile, Charpy, grain size and hardness in-house.
Jiangyin Jiangnan Metal Co., Ltd. employs approximately 460 people, including 9 senior engineers and 32 intermediate engineers. Customers retain the right to witness any production stage: chemistry analysis, forging, heat-treatment cycles, mechanical testing and final NDE. Witnessing is arranged with our QA team at no charge.
⚖ 2.4610 forging weight calculator
Pick a shape and dimensions to get net weight at density 8.6 g/cm³, plus an estimated rough forging weight for your RFQ.
Calculated at 2.4610 density 8.6 g/cm³. Net weight is the finished part; the rough forging weight adds your selected machining allowance and is the figure we quote against. Maximum single-piece capability in this grade is 5,000 kg.
Standards, testing and quality documentation
For 2.4610 orders the governing specifications are normally ASTM B574 / ASME SB-574 (rod and bar), ASTM B564 / ASME SB-564 (nickel-alloy forgings) and DIN 17744 with VdTÜV Werkstoffblatt 424 where European pressure-equipment approval is needed. Sour service adds NACE MR0175 / ISO 15156 or MR0103 / ISO 17945.
ISO 9001:2015
Certified quality management system covering forging, heat treatment, testing and despatch.
EN 10204 3.1 standard · 3.2 on request
3.2 issued through client-nominated bodies: Lloyd's, DNV, BV, ABS, TÜV, SGS.
UT to ASTM A388 · EN 10228-3 · SEP 1921
Acceptance class stated on the order. Reports issued with the certificate.
Liquid penetrant to ASTM E165 / EN ISO 3452
Magnetic particle is not applicable, because 2.4610 is non-magnetic.
ASTM G28 method A intergranular test
Available on request as evidence of correct annealing and non-sensitisation.
Heat number, PMI, marking
Positive material identification and hard-stamp or vibro-etch marking on a non-functional surface.
Quality gates and non-conformance handling
- Six mandatory hold points. Raw-material chemistry, forging temperature compliance, post-forging UT, heat-treatment chart approval, mechanical-test acceptance, final NDE and dimensional. Customer-witnessed hold points can be added at no charge.
- Non-conformance reports raised within 24 hours of any out-of-specification finding, with root-cause analysis completed within five working days and proposed disposition sent to you before any rework. No silent rework.
- Replacement guarantee. Material found non-conforming within six months of delivery, verified by independent third-party test, is replaced free of charge including freight. Documentation retained for ten years.
- Witness inspection right. Unrestricted access to any production stage, coordinated with our QA team.
How to specify a 2.4610 / UNS N06455 forging order
Seven steps. Following them removes essentially all of the ambiguity that causes requotes and rejected certificates on this grade.
- State the generic designation
Write UNS N06455 / W.-Nr. 2.4610 / NiMo16Cr16Ti. Avoid "Hastelloy C-4" on a purchase order. It is a Haynes International trademark, and a PO naming it can technically only be filled by that company.
- Name the product-form standard
ASTM B574 / ASME SB-574 for rod and bar; ASTM B564 / ASME SB-564 for forgings; DIN 17744 or VdTÜV Werkstoffblatt 424 for European pressure equipment. Where the equipment file needs it, specify VdTÜV limits, and one heat then satisfies all three.
- Specify the delivery condition
Solution annealed 1066 °C, rapid water quench. Never specify ageing or precipitation hardening on this grade.
- Supply the drawing
2D drawing or 3D model with dimensions, tolerances, machining allowance, surface roughness and any grain-flow requirement. State whether we supply as-forged, rough machined or finish machined.
- Define non-destructive examination
UT to ASTM A388, EN 10228-3 or SEP 1921 with the acceptance class, plus PT to ASTM E165 or EN ISO 3452 on machined surfaces. Do not call up magnetic particle testing, because the alloy is non-magnetic.
- Add corrosion and service requirements
Where relevant: intergranular corrosion test to ASTM G28 method A, NACE MR0175 / ISO 15156 or MR0103 / ISO 17945 compliance, PMI verification, and any restriction on cobalt for nuclear service.
- State certificate and commercial terms
EN 10204 3.1 or 3.2 with the nominated inspection body; then quantity, marking, delivery date, Incoterms and destination port.
Top 10 mistakes when ordering 2.4610 forgings
Compiled from RFQs and post-delivery audits on this grade. Every one of them costs nothing to catch at the specification stage and weeks to catch at goods-in.
1 · Specifying an ageing treatment
Carried over from a precipitation-hardening grade. 2.4610 is not age hardenable. Fix: specify solution anneal at 1066 °C + water quench, nothing else.
2 · Writing "Hastelloy C-4" on the PO
A trademark of Haynes International. Independent producers cannot legally supply under that name. Fix: use UNS N06455 / 2.4610 / NiMo16Cr16Ti.
3 · Calling up magnetic particle testing
2.4610 is austenitic and non-magnetic, so MT cannot work. Fix: specify liquid penetrant to ASTM E165 or EN ISO 3452.
4 · Assuming DIN, ASTM and VdTÜV limits are identical
They differ on C, Si, P, S and the Cr band, the elements that control thermal stability. Fix: name the standard, and specify VdTÜV 424 limits for code or welded high-temperature work.
5 · Omitting the UT acceptance class
"UT per ASTM A388" without a class is not a requirement, it is a suggestion. Fix: state the class and the scanning coverage.
6 · Choosing C-4 for strongly oxidising duty
C-4's chromium is at the low end of the C family. Fix: for hot oxidising or mixed acids use C-22, Alloy 59 or 690. See the comparison table.
7 · Skipping the re-anneal after cold straightening
Cold work beyond 7 % outer-fibre elongation changes SCC behaviour. Fix: require re-annealing after any cold straightening, and say so on the drawing.
8 · Forgetting the caustic stress-relief
Caustic service needs the 705 °C treatment; general service does not. Fix: declare the service medium on the enquiry so the route is set correctly.
9 · Quoting net weight instead of forging weight
Rough forging weight drives price, not finished weight. Fix: use the weight calculator and send both figures.
10 · Ordering to "typical" properties
780 MPa is a typical value, not a guaranteed minimum. Fix: design to the 690 MPa specification minimum and take allowable stresses from the applicable code.
2.4610 drawing callout template
Copy this block into the material callout box of your drawing. It is accepted under ASTM, ASME, EN and DIN practice and eliminates most ordering ambiguity on this grade.
| MATERIAL | UNS N06455 / W.-Nr. 2.4610 / NiMo16Cr16Ti per ASTM B574 / ASME SB-574 (bar) or ASTM B564 / SB-564 (forging) |
|---|---|
| CHEMISTRY | To DIN 17744 · VdTÜV WB 424 limits where code approval applies |
| CONDITION | Solution annealed 1066 °C, hold per section, rapid water quench NO ageing / precipitation treatment |
| MECHANICAL | Rm ≥ 690 MPa · Rp0.2 ≥ 276 MPa · A5 ≥ 40 % (longitudinal) |
| NDE (VOLUMETRIC) | UT per ASTM A388 (state class) or EN 10228-3 / SEP 1921 |
| NDE (SURFACE) | PT per ASTM E165 or EN ISO 3452 · MT not applicable (non-magnetic) |
| CORROSION TEST | IGC per ASTM G28 method A (state acceptance rate), optional |
| CERTIFICATION | EN 10204 3.1 mill certificate · or 3.2 with third-party witness |
| MARKING | Heat number, grade, standard, drawing number; vibro-etch on non-functional surface |
| SURFACE | State Ra on sealing and bearing surfaces; as-forged elsewhere |
📝 Instant 2.4610 RFQ generator
Fill in what you know and get a complete, correctly-worded enquiry ready to email, copy or send by WhatsApp.
Where is 2.4610 used?
2.4610 appears wherever a reducing acid or chloride stream meets a welded or thermally cycled component. The applications below are the service environments in which this grade is routinely specified; project references are available under confidentiality agreement on request.
HCl, H₂SO₄ and H₃PO₄ plant
Reactors, heat-exchanger tube sheets, exchanger flanges, nozzles, pump and agitator shafts, valve bodies in acid duty.
Flue-gas desulphurisation & waste incineration
Scrubber internals, quench-zone components and ducting flanges exposed to acid chloride condensate.
Bleaching systems
Chlorine dioxide and hypochlorite service: digesters, bleach towers, washer components.
Reactors and vessels
Acetic and formic acid duty, pesticide and fertiliser production, high-purity requirements.
Sour and chloride service
Wellhead and process components qualified under NACE MR0175 / ISO 15156 and MR0103 / ISO 17945.
Acid-bearing auxiliary systems
Where cobalt content must be restricted, state the limit on the enquiry so material is procured accordingly.
Glossary
- 2.4610
- EN / DIN material number for NiMo16Cr16Ti, the low-carbon nickel-molybdenum-chromium alloy also designated UNS N06455.
- UNS N06455
- Unified Numbering System designation for the same chemistry, and the safest name to write on a purchase order.
- NiMo16Cr16Ti
- EN chemical designation: nickel base with nominally 16 % molybdenum, 16 % chromium and a titanium stabiliser.
- Alloy C-4
- Generic industry name for this chemistry, not a trademark.
- Hastelloy® C-4
- Registered trademark of Haynes International, Inc. Generic equivalents: UNS N06455, 2.4610, NiMo16Cr16Ti.
- Sensitisation
- Precipitation of chromium carbides at grain boundaries, depleting adjacent chromium and opening a path for intergranular corrosion. 2.4610 is formulated to resist it.
- µ phase
- A brittle intermetallic that forms in Ni-Mo-Cr alloys on exposure around 650-1040 °C. Low silicon, low iron and the absence of tungsten suppress it in 2.4610.
- Knife-line attack
- Narrow band of intergranular corrosion immediately adjacent to a weld in a stabilised alloy. Not observed in correctly produced 2.4610.
- Solution annealing
- Heating to 1066 °C to dissolve precipitates and homogenise the structure, followed by rapid water quench to hold them in solution. The only heat treatment applied to this grade.
- PREN
- Pitting Resistance Equivalent Number, here Cr + 3.3 × Mo. 2.4610 ≈ 67 against ≈ 25 for 316L.
- ASTM G28 method A
- Boiling ferric-sulphate / sulphuric-acid test used to verify that a nickel alloy has been correctly annealed and is not sensitised.
- EN 10204 3.1
- Inspection certificate issued by the manufacturer's independent inspection department. 3.2 adds a third-party or customer witness.
- VdTÜV Werkstoffblatt 424
- German material sheet for NiMo16Cr16Ti, used for European pressure equipment. Tighter than DIN 17744 on C, Si, P, S and the Cr band.
- Trepanned billet
- Bar with the centre bored out before forging, used for hollow shafts to cut raw-material input and machining time.
Frequently asked questions about 2.4610 / UNS N06455
What is 2.4610?
2.4610 is the EN / DIN material number for NiMo16Cr16Ti, a low-carbon austenitic nickel-molybdenum-chromium alloy also designated UNS N06455 and known commercially as Alloy C-4. It contains roughly 65 % nickel, 14.0-18.0 % chromium and 14.0-17.0 % molybdenum, with carbon held to 0.015 % max, silicon to 0.08 % max and a titanium addition up to 0.70 % for stabilisation. Its defining property is exceptional thermal stability: it resists the precipitation of carbides and intermetallic phases between 650 and 1040 °C, so it retains ductility and resistance to intergranular corrosion after welding or long high-temperature exposure.
Is 2.4610 the same as Alloy C-4, UNS N06455 and Hastelloy C-4?
They describe the same chemistry. 2.4610 is the EN / DIN material number, NiMo16Cr16Ti is the EN chemical designation, and UNS N06455 is the American Unified Numbering System designation. Hastelloy C-4 is a registered trademark of Haynes International, Inc.; Nicrofer 6616 hMo is VDM Metals' brand and BÖHLER L004 is voestalpine's. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with those trademark holders and supplies the material correctly described as UNS N06455 / 2.4610 / NiMo16Cr16Ti.
What is the chemical composition of 2.4610?
Per DIN 17744 for NiMo16Cr16Ti (2.4610): carbon 0.015 % max, silicon 0.08 % max, manganese 1.00 % max, phosphorus 0.025 % max, sulphur 0.015 % max, chromium 14.0-18.0 %, molybdenum 14.0-17.0 %, titanium 0.70 % max, iron 3.0 % max, cobalt 2.0 % max, copper 0.50 % max, nickel balance. VdTÜV Werkstoffblatt 424 is tighter still, requiring carbon 0.009 % max, silicon 0.050 % max and chromium 14.5-17.5 %. Full table in section 4.
What are the mechanical properties of 2.4610?
In the solution-annealed condition at room temperature, ASTM B574 / ASME SB-574 requires a minimum tensile strength of 690 MPa (100 ksi), a minimum 0.2 % proof strength of 276 MPa (40 ksi) and minimum elongation of 40 %. European practice to DIN 17744 and VdTÜV 424 requires Rm ≥ 700 MPa and Rp0.2 ≥ 305 MPa. Typical measured values on forged and annealed product are around 780 MPa tensile, 360 MPa proof strength and 55 % elongation. The modulus of elasticity is 211 GPa.
What is the density of 2.4610?
The density of 2.4610 / Alloy C-4 / UNS N06455 is 8.6 g/cm³, equivalent to 0.311 lb/in³. That value is used in the forging weight calculator on this page.
How is 2.4610 heat treated?
2.4610 is solution annealed at 1066 °C (1950 °F) and then water quenched; rapid air cooling is acceptable only for sections thinner than about 10 mm. Hold time at temperature is 10 to 30 minutes depending on thickness. The alloy is not age hardenable and is strengthened only by cold work, so any ageing or precipitation-hardening cycle is incorrect and will degrade corrosion resistance. Re-annealing is required after all hot forming and after cold forming that produces 7 % or more outer-fibre elongation.
What is the forging temperature range for 2.4610?
Hot forging starts at 1177 °C (2150 °F) and must finish above 954 °C (1750 °F). The window is narrow and the alloy is sensitive to strain rate, so moderate reductions with frequent reheating are used. Forging below the finish temperature risks cracking. After forging the part is solution annealed at 1066 °C and water quenched to restore corrosion resistance.
What is the difference between 2.4610 (C-4) and Hastelloy C-276?
Both are nickel-molybdenum-chromium alloys, but 2.4610 / C-4 contains no tungsten, has very low iron and silicon, and carries a titanium stabiliser. That chemistry gives it markedly better thermal stability: it resists precipitation of carbides and µ phase between 650 and 1040 °C, so it does not sensitise or suffer knife-line attack in the weld heat-affected zone. C-276 contains 3-4.5 % tungsten and 4-7 % iron, giving slightly better performance in some strongly oxidising and mixed-acid media, but it is more prone to precipitation after high-temperature exposure. Choose C-4 where thermal stability, welded fabrication or elevated-temperature exposure dominates; choose C-276 for oxidising and mixed-acid duty. Full comparison in section 10.
Is 2.4610 resistant to chloride stress corrosion cracking?
Yes. With approximately 65 % nickel, 2.4610 is practically immune to chloride-induced stress corrosion cracking, including in hot chloride solutions where austenitic stainless steels such as 304 and 316L fail. Its pitting resistance equivalent number, calculated as chromium plus 3.3 times molybdenum, is about 67, far above the threshold for chloride pitting and crevice attack in seawater.
Does 2.4610 need post-weld heat treatment?
For most services no post-weld heat treatment is required, which is a principal practical advantage of the grade, because its thermal stability means the heat-affected zone does not sensitise. Two exceptions apply: for caustic service a stress relief at about 705 °C held for at least 30 minutes per 25 mm of thickness is used, and where a design code or the purchase specification requires it, a full solution anneal at 1065-1080 °C with rapid water quench restores base-metal properties.
Which standards apply to 2.4610 forgings?
Rod and bar are covered by ASTM B574 / ASME SB-574; nickel-alloy forgings by ASTM B564 / ASME SB-564; plate, sheet and strip by ASTM B575 / ASME SB-575; seamless and welded pipe and tube by ASTM B622, B619 and B626; fittings by ASTM B366. European coverage is DIN 17744 and DIN 17752, with VdTÜV Werkstoffblatt 424 for pressure equipment. Sour service is governed by NACE MR0175 / ISO 15156 and NACE MR0103 / ISO 17945. Inspection documents are issued to EN 10204 3.1 or 3.2.
What is the maximum forging size available in 2.4610?
Jiangyin Jiangnan Metal Co., Ltd. produces 2.4610 / UNS N06455 seamless rolled rings up to 2,000 mm outside diameter, forged discs up to Ø 1,500 mm, forged shafts up to 6,000 mm length and bar from 20 to 400 mm diameter, with single-piece weights up to 5,000 kg. Nickel alloys have a narrower hot-working window than steel, so maximum sizes are lower than for our stainless or carbon-steel forgings.
What is the lead time for 2.4610 forgings?
Typical lead time is 6 to 10 weeks from order confirmation, depending on raw-material availability, section size and machining scope. Orders requiring EN 10204 3.2 third-party witnessed certification, intergranular corrosion testing to ASTM G28 or NACE compliance documentation typically extend to 10 to 14 weeks.
Is 2.4610 magnetic?
No. 2.4610 / UNS N06455 has a fully austenitic microstructure in the solution-annealed condition and is essentially non-magnetic, with relative permeability close to 1.0. A magnet test is therefore a quick field screen to distinguish it from martensitic or duplex grades, though it cannot distinguish it from other austenitic nickel alloys. It also means magnetic particle inspection cannot be used, so specify liquid penetrant instead.
Where is 2.4610 used?
2.4610 / Alloy C-4 is specified for chemical process equipment handling hydrochloric, sulphuric, phosphoric, formic and acetic acids; flue-gas desulphurisation scrubbers and waste-incineration plant; pulp and paper bleaching systems; pharmaceutical and agrochemical reactors; and components exposed to wet chlorine, hypochlorite and chlorine dioxide. Typical forged items are heat-exchanger tube sheets, reactor flanges, valve bodies, pump shafts, agitator shafts, nozzles and seamless rolled rings.
How do you machine 2.4610?
Machine in the solution-annealed condition. The alloy work hardens faster than austenitic stainless steel, so use rigid setups, sharp positive-rake carbide tooling, reduced cutting speed of roughly 15 to 25 m/min for turning, generous positive feed, and a depth of cut that stays below the previously work-hardened layer. Never allow the tool to dwell or rub. Flood coolant is recommended and chip breaking should be positively controlled.
Technical references
Chemistry, mechanical, physical, heat-treatment and corrosion data on this page are drawn from the published standards and manufacturer data sheets listed below. Test results reported on our material certificates are independent and traceable to calibrated equipment.
- DIN 17744, Nickel wrought alloys with molybdenum and chromium: chemical composition, Deutsches Institut für Normung.
- DIN 17752, Nickel and nickel alloy rod and bar: technical delivery conditions.
- DIN 17751, Nickel and nickel alloy plate, sheet and strip: technical delivery conditions.
- ASTM B574 / ASME SB-574, Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum … Alloy Rod, ASTM International.
- ASTM B564 / ASME SB-564, Standard Specification for Nickel Alloy Forgings, ASTM International.
- ASTM B575 / ASME SB-575, Low-Carbon Nickel-Molybdenum-Chromium … Alloy Plate, Sheet and Strip, ASTM International.
- ASTM B622 / B619 / B626, seamless and welded pipe and tube specifications for nickel alloys, ASTM International.
- ASTM B366, Factory-Made Wrought Nickel and Nickel Alloy Fittings, ASTM International.
- VdTÜV Werkstoffblatt 424, NiMo16Cr16Ti (2.4610), Verband der TÜV e.V.
- ASTM G28, Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys, method A.
- ASTM A388, Standard Practice for Ultrasonic Examination of Steel Forgings, ASTM International.
- EN 10228-3, Non-destructive testing of steel forgings: ultrasonic testing of ferritic or martensitic steel forgings, CEN.
- SEP 1921, Stahl-Eisen-Prüfblatt, ultrasonic testing of forgings.
- ASTM E165 / EN ISO 3452, liquid penetrant testing.
- EN 10204:2004, Metallic products: types of inspection documents, CEN.
- NACE MR0175 / ISO 15156-3, Materials for use in H₂S-containing environments in oil and gas production: cracking-resistant CRAs.
- NACE MR0103 / ISO 17945, materials resistant to sulphide stress cracking in corrosive petroleum refining environments.
- AWS A5.14 / SFA-5.14, Nickel and Nickel-Alloy Bare Welding Electrodes and Rods (ERNiCrMo-7).
- Haynes International, HASTELLOY® C-4 alloy: principal features, fabrication and heat treatment, manufacturer brochure.
- VDM Metals, VDM® Alloy C-4 / Nicrofer 6616 hMo, material data sheet No. 4124.
- voestalpine BÖHLER Edelstahl, BÖHLER L004: 2.4610 / N06455 / Alloy C4, product data sheet.
- ASME Boiler and Pressure Vessel Code, Section II Part B and Part D, latest edition, for allowable design stresses.
Standards cited are the revisions known at the time of the last page review. For procurement, always reference the revision in force at the contract date. All trademarks are the property of their respective owners.
Request a 2.4610 / UNS N06455 quotation
Send the drawing, the dimensions, or just the service conditions. Our engineering team replies within 24 hours with price, lead time and confirmation of the applicable standards. If you are not yet sure whether 2.4610 is the right grade for your duty, tell us the medium, concentration and temperature and we will tell you, including when a different alloy would serve you better.