Section 01
Why This Comparison Causes Specification Errors
In 25 years of exporting nickel alloy forgings to more than 50 countries, one situation repeats with costly regularity: a procurement engineer in Houston specifies "C-276 equivalent," a buyer in Frankfurt requests "DIN 2.4819," and a third stakeholder in Tokyo asks for "NCF 276." None realizes they may — or may not — be describing the same material, depending on whether the project demands Fe ≤ 1.25%.
Both 2.4708 (NiMo22Cr15) and 2.4819 (NiMo16Cr15W) belong to the same Ni-Mo-Cr superalloy family. Both pass NACE MR0175 sour service testing. Both are produced by the same forging shops — including ours. But the differences in their chemistry translate directly into different performance in nuclear power, LNG cryogenic service, and concentrated hydrochloric acid environments. Choosing the wrong alloy is not a minor substitution; it can trigger qualification failures and material rejection.
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Scope of This Guide
This comparison covers open die forgings and seamless rolled rings in both alloys — the product forms we manufacture. All corrosion data is drawn from EN 10204 3.1 factory certificates and customer field reports across 25 years. Where one alloy outperforms the other, we explain the metallurgical reason. Where performance is equal, we say so directly — including when you can save money by choosing 2.4819.
Section 02
2.4708 vs 2.4819: Alloy Specifications at a Glance
DIN EN · Best for Reducing Acids · High-Purity
2.4708
NiMo22Cr15
UNS EquivalentN10276 (purer grade)
Molybdenum (Mo)21.5 – 23.0%
Chromium (Cr)13.8 – 15.6%
Tungsten (W)None
Iron (Fe) Limit≤ 1.25%
Nickel (Ni)Balance ~60%
Typical PREN> 65
Key StandardsDIN EN, UNS N10276, ASTM B564
DIN EN · Standard C-276 Type · Cost Effective
2.4819
NiMo16Cr15W
UNS EquivalentN10276 (standard grade)
Molybdenum (Mo)15.0 – 17.0%
Chromium (Cr)14.5 – 16.5%
Tungsten (W)3.0 – 4.5%
Iron (Fe) Limit≤ 5.0%
Nickel (Ni)Balance ~57%
Typical PREN> 60
Key StandardsDIN EN, ASTM B564, API
Two numbers reveal the engineering trade-off immediately. First, 2.4708 carries 6–7% more molybdenum than 2.4819 — molybdenum is the primary driver of resistance to reducing acids, including hydrochloric acid and dilute sulfuric acid, which is why 2.4708 consistently outperforms 2.4819 in HCl and H₂SO₄ environments. Second, 2.4819 adds tungsten (W) at 3–4.5%, which improves stability in mixed oxidizing/reducing environments — an advantage in applications where the corrosive medium alternates between reducing and oxidizing conditions.
The iron limit is the third critical differentiator. At Fe ≤ 1.25%, 2.4708 is four times purer than 2.4819's Fe ≤ 5.0% allowance. This is not a minor specification detail — it is the defining requirement for nuclear-qualified forgings under RCC-M (France) and KTA (Germany) standards, and it measurably improves Charpy V-notch impact values at −196°C for cryogenic LNG service.
Section 03
Chemical Composition: 2.4708 vs 2.4819 Element by Element
| Element |
2.4708 (NiMo22Cr15) |
2.4819 (NiMo16Cr15W) |
Engineering Significance |
| Carbon (C) | ≤ 0.010% | ≤ 0.010% | Identical. Ultra-low carbon controls weld sensitization and inter-granular corrosion in both alloys. |
| Molybdenum (Mo) | 21.5 – 23.0% | 15.0 – 17.0% | Critical difference. 2.4708 has 6–7% more Mo — the primary factor in reducing acid resistance. Directly responsible for 2.4708's superior HCl and H₂SO₄ corrosion rates. |
| Chromium (Cr) | 13.8 – 15.6% | 14.5 – 16.5% | Slightly higher in 2.4819. Higher Cr contributes to resistance in mildly oxidizing environments and provides a modest advantage in mixed acid service. |
| Tungsten (W) | None | 3.0 – 4.5% | 2.4819 advantage. Tungsten stabilizes the passive film during transient oxidizing conditions, improving performance in mixed HNO₃ + HCl environments and oscillating acid service. |
| Iron (Fe) | ≤ 1.25% | ≤ 5.0% | Nuclear and cryogenic critical. 2.4708's Fe limit is 4× stricter. RCC-M (France) and KTA (Germany) nuclear codes mandate Fe ≤ 1.25%. Lower Fe also reduces ferrite inclusions, directly improving Charpy impact at −196°C. |
| Silicon (Si) | ≤ 0.08% | ≤ 0.08% | Identical. Controlled for forgeability and weld quality. Low Si reduces hot-tearing risk during open die forging of large cross-sections. |
| Nickel (Ni) | Balance (~60%) | Balance (~57%) | Higher Ni in 2.4708 results from lower Fe and absence of W. Elevated Ni content contributes to cryogenic toughness and overall matrix stability. |
| Manganese (Mn) | ≤ 0.50% | ≤ 1.00% | Lower Mn limit in 2.4708 supports cleaner microstructure for high-purity applications requiring rigorous iron content control. |
Global Standard Cross-Reference: What Different Countries Call These Alloys
2.4708 (NiMo22Cr15) corresponds to UNS N10276 (purer grade, Fe ≤ 1.25%), JIS NCF 276 (Japan), ASTM B564 product form (USA/Canada with dual cert), ISO 9722 NW 0276, and is referenced in RCC-M / KTA nuclear project specifications (France/Germany) for material purity requirements. Chinese domestic equivalent: NS334 (GB/YB — export orders always carry DIN EN cert).
2.4819 (NiMo16Cr15W) corresponds to the standard UNS N10276 / C-276 type alloy (UNS N10276) (Fe ≤ 5.0%), ASTM B574 / B575 / B564, JIS NCF 276 (same designation, standard grade), and most international commercial "C-276" specifications. This is the alloy most buyers mean when they specify "C-276 equivalent" without an iron content restriction.
If your RFQ specifies only "C-276 equivalent" without restricting Fe content, our engineering team will always confirm which standard governs your project before issuing a quotation — to prevent the Fe content mismatch issue that has caused TÜV audit failures for several customers.
Section 04
Corrosion Performance: 10-Environment Comparison with Real Field Data
Every alloy supplier claims "excellent corrosion resistance." What procurement engineers actually need is corrosion rates across specific environments at specific concentrations and temperatures — data that lets them compare without relying on marketing language. The table below is built from EN 10204 3.1 factory certificates, third-party test reports, and 25 years of direct customer feedback from chemical plants, LNG terminals, desalination facilities, and oil & gas installations in more than 50 countries.
| Corrosive Environment |
2.4708 Rate |
2.4819 Rate |
Recommended Alloy |
| HCl 1–20%, 20–80°C | < 0.05 mm/yr | < 0.08 mm/yr | 2.4708 |
| HCl 20–37% concentrated, boiling | 0.1 – 0.5 mm/yr | 0.2 – 0.7 mm/yr | 2.4708 |
| H₂SO₄ 10–60%, up to 60°C | < 0.13 mm/yr | < 0.15 mm/yr | 2.4708 |
| H₂SO₄ > 80% oleum, > 60°C | 1.0 – 3.0 mm/yr | 0.8 – 2.5 mm/yr | 2.4819 (marginal advantage) |
| Mixed HNO₃ + HCl, oscillating | 0.3 – 0.8 mm/yr | 0.2 – 0.6 mm/yr | 2.4819 (W stabilizes) |
| H₃PO₄ up to 85%, 100°C | < 0.05 mm/yr | < 0.07 mm/yr | 2.4708 |
| Acetic acid (all concentrations, boiling) | < 0.025 mm/yr | < 0.03 mm/yr | 2.4708 |
| Seawater / 3.5% NaCl, ambient – 60°C | No measurable pitting | No measurable pitting | Equal |
| Sour gas H₂S + CO₂ (NACE MR0175) | No SCC detected | No SCC detected | Equal |
| HNO₃ > 30%, > 50°C (strongly oxidizing) | 1.0 – 5.0 mm/yr | 0.8 – 4.0 mm/yr | 2.4819 (slight advantage) |
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Neither alloy is suitable for concentrated nitric acid service
When customers specify "corrosion-resistant nickel alloy" for HNO₃ service above 30% concentration, we recommend Alloy 690 (2.4642) or 316L stainless instead. Both 2.4708 and 2.4819 suffer accelerated attack in strongly oxidizing acid — this is the most common material selection mistake we see, and we flag it at the inquiry stage rather than the test report stage.
Section 05
Mechanical Properties: Forging Performance Data
For most structural applications, both alloys deliver comparable mechanical performance after solution annealing and quenching heat treatment. The differences become project-decisive at cryogenic temperatures and in demanding project qualification testing, where the iron content limit directly affects measured impact values.
Yield Strength (Rp0.2)2.4708: ≥ 310 MPa2.4819: ≥ 283 MPa
Tensile Strength (Rm)2.4708: ≥ 725 MPa2.4819: ≥ 690 MPa
Elongation (A5)2.4708: ≥ 40%2.4819: ≥ 40%
Charpy Impact KV at −196°C (factory average)2.4708: 85 – 90 J2.4819: 70 – 78 J
Hardness (HB)2.4708: 180 – 240 HB2.4819: 180 – 240 HB
The cryogenic Charpy advantage of 2.4708 is directly traceable to its lower iron content. A matrix with Fe ≤ 1.25% contains fewer ferrite inclusions — the primary crack initiation sites under low-temperature impact loading. For LNG projects requiring Charpy V-notch testing at −196°C, 2.4708 averages 85–90 J in our factory data versus 70–78 J for 2.4819. Several of our Australian LNG customers have cited this margin specifically as their reason for choosing 2.4708 over the lower-cost 2.4819.
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Temperature Range for Both Alloys
Both 2.4708 and 2.4819 serve reliably from −196°C cryogenic up to approximately 450°C. Above 450°C in continuous oxidizing service, consider Alloy 625 (2.4856) which has superior high-temperature oxidation resistance. Neither 2.4708 nor 2.4819 should be specified for continuous operation above 500°C without detailed engineering review, as sigma-phase embrittlement becomes a risk in the 593–816°C range.
Section 06
Cost Index: Transparent Price Comparison
Molybdenum is one of the most expensive alloying elements on the market. Because 2.4708 carries 6–7% more Mo than 2.4819, and because high-purity 2.4708 (Fe ≤ 1.25%) requires VIM/VAR vacuum melting to achieve Fe ≤ 1.25%, it commands a price premium. For projects where the stricter Fe limit is not required by specification, 2.4819 offers equivalent corrosion resistance in most environments at a meaningfully lower cost.
2.4708 Nuclear (VIM+VAR)
Highest
2.4708 Commercial
Baseline
2.4819 Standard
~5 – 10% less
Alloy 625 / 2.4856
Reference
2205 Duplex (reference)
Much lower
Our sales team proactively recommends 2.4819 when your specification does not require Fe ≤ 1.25% — because we supply both alloys and have no commercial incentive to push the higher-cost option when it is not needed. This transparent approach is why customers from 50+ countries return to us for repeat orders.
Section 07
Decision Matrix: 2.4708 vs 2.4819 by Project Scenario
| Project Scenario |
2.4708 NiMo22Cr15 |
2.4819 NiMo16Cr15W |
| Reducing acid service — HCl, dilute H₂SO₄ | ✅ First choice — higher Mo content delivers lower corrosion rates | Good, but lower Mo gives marginally higher corrosion rate |
| Nuclear power — RCC-M (France) / KTA (Germany) | ✅ Only option — Fe ≤ 1.25% is mandatory | ❌ Fe ≤ 5.0% fails nuclear material qualification inspection |
| Oil & gas sour service — NACE MR0175 / ISO 15156 | ✅ Fully compliant | ✅ Fully compliant — both alloys equal |
| LNG cryogenic service — −196°C Charpy testing | ✅ Preferred — purer matrix yields higher average Charpy impact | Passes minimum spec, but lower Charpy margin (70–78 J vs 85–90 J) |
| Mixed oxidizing / reducing acid service | Adequate, but no tungsten addition for oxidizing transients | ✅ W addition stabilizes passive film during oxidizing excursions |
| Seawater / subsea chloride environment | ✅ Excellent — PREN > 65, no measurable pitting in 3-year test | ✅ Excellent — PREN > 60, equal in practical subsea service |
| Phosphate fertilizer plant — H₃PO₄ service | ✅ Best-in-class for phosphoric acid at all concentrations | Very good — corrosion rate ~0.07 mm/yr vs <0.05 for 2.4708 |
| Budget-constrained project, mild acid service | Overkill on iron purity; pays premium that is not needed | ✅ 5–10% material cost saving with equal corrosion performance in mild service |
| High-purity / vacuum-melt traceability required | ✅ VIM+VAR route available, Fe ≤ 1.25% certified, full heat trace | VAR available, but higher Fe allowance may not meet all high-purity project specifications |
Section 08
Real Project Case Studies: How Customers Chose Between the Two Alloys
The following cases are drawn from actual Jiangsu Liangyi orders. Project details are shared with customer consent; confidential specifics have been generalized.
Middle East · Saudi Arabia · 2022
Wellhead Casing Heads & Valve Bodies — API 6A / NACE MR0175 / 15,000 PSI Sour Service
The customer's specification required NACE MR0175 sour service compliance and API 6A product acceptance. Iron content was unrestricted by the project specification. After engineering review, our team recommended 2.4819 — identical NACE compliance to 2.4708, with a 7% material cost reduction on a 120-tonne order. The customer confirmed cost saving with no performance compromise.
Chose 2.4819 — equal NACE compliance, 7% cost saving
Europe · France + Germany · PWR Nuclear · 2021
Reactor Coolant Pump Casings — RCC-M Qualified, VIM+VAR Melting Route
The project specification followed RCC-M (French nuclear standard), which mandates Fe ≤ 1.25% with full heat traceability. We supplied 2.4708 forgings meeting the Fe ≤ 1.25% composition requirement, with EN 10204 3.2 documentation. Independent third-party inspection was arranged by the customer’s designated inspection authority.
Chose 2.4708 — nuclear Fe purity requirement non-negotiable
North America · United States · Chemical Plant · 2023
HCl Synthesis Reactor Tube Sheets & Pump Casings — 20–35% HCl, 60–75°C
This customer had previously used 2.4819 forgings in their HCl synthesis reactor and observed higher-than-expected pit depth on tube sheet faces after 18 months of service. Our engineering team reviewed their process conditions (20–35% HCl, 60–75°C) and recommended switching to 2.4708. Post-switch inspection after 24 months showed corrosion rates reduced by approximately 40%.
Switched to 2.4708 — 40% reduction in corrosion rate confirmed
Asia-Pacific · Australia · LNG Terminal · 2021
Cryogenic Valve Bodies & Piping Flanges — −196°C Charpy V-notch Required
Project specification required Charpy V-notch ≥ 75 J at −196°C for all valve bodies and flanges in LNG service. Both alloys technically satisfy the minimum requirement. The customer's QA team selected 2.4708 after reviewing our factory test data: 2.4708 averaged 85–90 J versus 70–78 J for 2.4819. Parts have operated in continuous LNG cryogenic service since 2021 with no issues.
Chose 2.4708 — cryogenic Charpy margin 15 J higher on average
Section 09
Manufacturing Capabilities for 2.4708 and 2.4819 Forgings
Jiangsu Liangyi Co., Limited has produced both 2.4708 (NiMo22Cr15) and 2.4819 (NiMo16Cr15W) open die forgings and seamless rolled rings since 1997. Our 80,000 m² facility in Jiangyin, Jiangsu Province operates a complete in-house production chain — from raw material melting through final CNC machining — with no outsourcing at any stage.
Key manufacturing capabilities include: 6,300-ton hydraulic forging press (single-piece weight up to 30 tonnes); 5-metre seamless ring rolling mill (ring diameter up to 6,000 mm); in-house 30t EAF + LF + VOD steelmaking for standard grades; VIM (vacuum induction melting) and VAR (vacuum arc remelting) routes available for high-purity 2.4708 with Fe ≤ 1.25%; 100% UT testing per SEP 1923 quality class 2b; EN 10204 3.1 / 3.2 material test certificates as standard.
All forgings are supplied with full traceability from raw material heat number through final delivery, and can be accompanied by SGS, Bureau Veritas (BV), TÜV, or other customer-nominated third-party inspection by prior arrangement.
Frequently Asked Questions
2.4708 vs 2.4819: Common Questions Answered
Is 2.4708 the same as UNS N10276 (C-276 type alloy (UNS N10276))?
Not exactly. Both 2.4708 (NiMo22Cr15) and UNS N10276 are closely related but have distinct composition limits. The most critical difference is the iron limit: 2.4708 requires Fe ≤ 1.25%, while standard UNS N10276 allows Fe up to 5.0%. For most industrial applications corrosion performance is similar, but the Fe limit is mandatory for nuclear-qualified forgings under RCC-M and KTA standards. Always confirm which standard governs your project before specifying either designation.
Can 2.4819 replace 2.4708 on a nuclear power project if delivery is urgent?
No. On RCC-M or KTA qualified nuclear projects, Fe ≤ 1.25% is a mandatory material requirement — not a preference that can be waived. 2.4819 with Fe ≤ 5.0% will fail the incoming material qualification inspection. Contact Jiangsu Liangyi early for urgent nuclear orders: we maintain stock of 2.4708 forgings and can reduce lead time to 3–4 weeks for available sizes.
Which alloy performs better in hydrochloric acid (HCl) service?
2.4708 (NiMo22Cr15) consistently outperforms 2.4819 in HCl service due to its higher molybdenum content (21.5–23.0% vs 15.0–17.0%). In 1–20% HCl at 20–80°C, 2.4708 achieves corrosion rates below 0.05 mm/year versus below 0.08 mm/year for 2.4819. At 20–37% HCl at boiling point, 2.4708 maintains 0.1–0.5 mm/year versus 0.2–0.7 mm/year for 2.4819. For HCl synthesis reactors, pickling equipment, and chlorine absorption towers, 2.4708 is the correct specification.
Which alloy is better for cryogenic LNG service at −196°C?
2.4708 is the preferred alloy for cryogenic LNG service. Its lower iron content (Fe ≤ 1.25%) produces a cleaner microstructure with fewer ferrite inclusions — the primary crack initiation sites under low-temperature impact loading. Factory Charpy V-notch test data shows 2.4708 averaging 85–90 J at −196°C versus 70–78 J for 2.4819. Both alloys meet minimum specifications, but 2.4708 provides a larger safety margin that several Australian LNG customers have cited as their selection rationale.
What is the cost difference between 2.4708 and 2.4819 forgings?
2.4708 typically costs 5–10% more than 2.4819 on raw material for commercial applications, primarily due to its higher molybdenum content. For high-purity 2.4708 with Fe ≤ 1.25%, produced via VIM+VAR vacuum melting where required by project specification, the premium over commercial 2.4819 can reach 15–30%. For non-nuclear projects where Fe ≤ 1.25% is not required by specification, 2.4819 is a rational cost-saving choice with equal performance in most applications.
Do you provide EN 10204 3.1 and 3.2 certificates for both alloys?
Yes. Jiangsu Liangyi supplies EN 10204 3.1 mill test certificates as standard for all 2.4708 and 2.4819 forgings, covering heat number, chemical analysis, manufacturing route, heat treatment records, mechanical test results, NDT reports, and dimensional data. EN 10204 3.2 certificates with independent third-party verification (SGS, Bureau Veritas, TÜV, or customer-nominated inspector) are available by prior arrangement upon customer request. Dual-standard DIN EN + ASTM/UNS N10276 certification covering ASTM B564, B462, or B472 is also available for North American customers.