Hangbo Alloy Group
Shanghai · Est. 2012
UNS N06985 / W.Nr 2.4619 (EN NiCr22Mo7Cu) — Nickel-chromium-molybdenum-copper corrosion-resistant alloy for wet phosphoric acid, sulfuric & nitric acid, and flue-gas-desulfurization (FGD) service. Manufacturer & global supplier.
Hastelloy G-3 (UNS N06985, W.Nr 2.4619, EN NiCr22Mo7Cu) is a nickel-chromium-iron alloy with deliberate additions of molybdenum and copper. It is the improved, lower-carbon successor to Hastelloy G-2, engineered to deliver a broad, well-balanced resistance to both oxidizing and reducing chemical environments while being exceptionally easy to weld.
The key design change versus G-2 is the ultra-low carbon (≤0.015%) together with tighter control of silicon and other minor elements. This dramatically reduces the risk of intergranular and knife-line attack in the weld heat-affected zone (HAZ) and improves overall fabricability. Chromium provides resistance to oxidizing acids such as nitric acid and wet chlorine, while nickel, molybdenum, and copper provide resistance to reducing acids — most notably wet phosphoric acid and sulfuric acid. These attributes make Hastelloy G-3 a standard material for phosphoric-acid production, acid recovery, and flue-gas-desulfurization (FGD) systems.
Hangbo Alloy Group supplies Hastelloy G-3 as plate, sheet, strip, bar, seamless and welded pipe/tube, fittings, and matching welding consumables, all solution-annealed and certified — a dependable Hastelloy G-3 supplier for global chemical and environmental projects.
Hangbo Alloy Group manufactures and supplies Hastelloy G-3 (UNS N06985 / W.Nr 2.4619) plate, sheet, bar, seamless & welded pipe/tube, fittings, and ERNiCrMo-12 welding consumables — all solution-annealed with full material certification.
Hastelloy G-3 achieves its balanced corrosion resistance through a synergistic mix of chromium (oxidizing resistance), molybdenum (reducing acid, pitting and crevice resistance), and copper (sulfuric and phosphoric acid resistance). The high iron content reduces cost and improves formability, while the ultra-low carbon prevents sensitization and intergranular corrosion after welding.
| Element | Standard Range (wt%) | Typical Value | Role in the Alloy |
|---|---|---|---|
| Nickel (Ni) | Balance | ~46 | Austenitic matrix; SCC resistance in chlorides |
| Chromium (Cr) | 21.0 – 23.5 | 22.2 | Oxidizing-acid & wet-chloride resistance |
| Iron (Fe) | 18.0 – 21.0 | 19.5 | Cost control; formability |
| Molybdenum (Mo) | 6.0 – 8.0 | 7.0 | Reducing-acid; pitting & crevice resistance |
| Copper (Cu) | 1.5 – 2.5 | 1.9 | Sulfuric & phosphoric acid resistance |
| Cobalt (Co) | ≤ 5.0 | 2.0 | Solid-solution; minor |
| Tungsten (W) | ≤ 1.5 | 1.0 | Strength; pitting resistance |
| Niobium + Tantalum (Nb+Ta) | ≤ 0.50 | 0.3 | Stabilization |
| Carbon (C) | ≤ 0.015 | 0.010 | Prevents sensitization / IG corrosion |
| Manganese (Mn) | ≤ 1.0 | 0.8 | Deoxidation; sulfur control |
| Silicon (Si) | ≤ 1.0 | 0.4 | Deoxidation; controlled for HAZ stability |
| Phosphorus (P) | ≤ 0.04 | 0.020 | Impurity control |
| Sulfur (S) | ≤ 0.03 | 0.010 | Impurity control for hot ductility |
The physical properties of Hastelloy G-3 are typical of nickel-base corrosion-resistant alloys: moderate density, low thermal conductivity, and a thermal-expansion coefficient close to that of austenitic stainless steels.
| Property | Value | Notes |
|---|---|---|
| Density | 8.14 g/cm³ (0.294 lb/in³) | Typical |
| Melting Range | 1260 – 1343 °C (2300 – 2450 °F) | Solidus – liquidus |
| Thermal Expansion (20–100°C) | ~14.6 × 10−6 /°C | Mean coefficient |
| Thermal Expansion (20–600°C) | ~15.1 × 10−6 /°C | Mean coefficient |
| Thermal Conductivity | ~10.0 W/(m·K) at 25°C | Low |
| Specific Heat | ~453 J/(kg·K) | At room temperature |
| Modulus of Elasticity | ~199 GPa (28.9 × 10³ ksi) | Tension, RT |
| Magnetic Properties | Non-magnetic (austenitic) | |
The following are typical minimum and typical values for solution-annealed product forms (sheet, plate, bar, pipe):
| Property | Typical / Minimum Value | Condition |
|---|---|---|
| Tensile Strength (Rm) | ≥ 621 MPa (90 ksi); typ. ~690 MPa | Solution-annealed |
| Yield Strength (Rp0.2) | ≥ 241 MPa (35 ksi); typ. ~320 MPa | Solution-annealed |
| Elongation (A) | ≥ 45%; typ. ~50% | Solution-annealed |
| Hardness | ≤ 100 HRB | Solution-annealed |
Hastelloy G-3 is a corrosion-resistant alloy, not a high-temperature creep alloy. It is suitable for long-term pressure service up to about 400°C (with short excursions to ~550°C). Above roughly 420°C under sustained load, sigma-phase embrittlement can occur, so it is not used for high-temperature creep components.
Hastelloy G-3 has excellent weldability and very low sensitivity to weld cracking. Its ultra-low carbon prevents sensitization and intergranular corrosion in the heat-affected zone, so fabricated equipment can often be placed in service without post-weld heat treatment. It is joined by GTAW (TIG), GMAW (MIG), and SMAW using matching or over-alloyed fillers (ASME welding group F-No. 44).
| Item | Recommendation |
|---|---|
| Bare wire / rod | ERNiCrMo-12 (AWS A5.14) |
| Covered electrode | ENiCrMo-12 (AWS A5.11) |
| Over-alloyed option | ERNiCrMo-10 / ENiCrMo-10 |
| Shielding gas (GTAW/GMAW) | High-purity argon; argon-helium mixes |
| Post-weld heat treatment | Normally not required |
| Surface preparation | Clean, degreased; avoid contamination, use dedicated tools |
Contact Hangbo Alloy Group for certified Hastelloy G-3 (UNS N06985) plate, pipe, bar, fittings, and ERNiCrMo-12 welding consumables. Competitive Hastelloy G-3 price, fast delivery, full EN 10204 3.1 MTR and third-party inspection.
The balanced chemistry of Hastelloy G-3 gives it unusually broad resistance to general and localized corrosion as well as to stress-corrosion cracking:
Hangbo Alloy Group supplies Hastelloy G-3 (UNS N06985 / W.Nr 2.4619) in all standard product forms, solution-annealed and certified to ASTM/ASME specifications:
| Product Form | Applicable Standard | Typical Size Range |
|---|---|---|
| Plate, Sheet, Strip | ASTM B582 / ASME SB582 | 0.5 – 100 mm plate; coils/strip 0.1 – 12 mm |
| Bar, Rod, Forgings | ASTM B581 / ASME SB581 | Diameter 5 – 300 mm |
| Seamless Pipe & Tube | ASTM B622 / ASME SB622 | OD 6 – 219 mm |
| Welded Pipe & Tube | ASTM B619 / B626 | Custom (ERW/EFW) |
| Fittings & Flanges | ASTM B366 / ASME SB366 | Elbows, tees, reducers, WNRF/SO/blind |
| Welding Consumables | AWS A5.14 ERNiCrMo-12 | Wire 0.8 – 2.4 mm; electrodes |
All products are supplied with EN 10204 Type 3.1 material certificates (chemical analysis, mechanical test results, and conformance to the ordered ASTM/ASME specification).
| Standard | Description |
|---|---|
| UNS N06985 | Unified Numbering System designation |
| W.Nr 2.4619 / EN NiCr22Mo7Cu | German / European designation |
| ASTM B581 | Bar, rod, and forgings |
| ASTM B582 | Plate, sheet, and strip |
| ASTM B619 / B622 / B626 | Welded pipe / seamless pipe & tube / welded tube |
| ASTM B366 | Factory-made wrought fittings |
| ASME SB equivalents | BPVC material specifications (SB581, SB582, SB619, SB622, SB626, SB366) |
| NACE MR0175 / ISO 15156 | Sour (H₂S) oil & gas service |
| GB NS3403 | Chinese equivalent grade |
| AWS A5.14 / A5.11 | ERNiCrMo-12 / ENiCrMo-12 welding consumables |
| Property | Hastelloy G-3 | Hastelloy G-2 | Hastelloy C-276 | Hastelloy C-22 |
|---|---|---|---|---|
| UNS | N06985 | N06975 | N10276 | N06022 |
| Nominal Cr % | 22 | ~22 | 15 | 21 |
| Nominal Mo % | 7 | ~18 | 16 | 13 |
| Cu % | 1.5 – 2.5 | ≤ 0.5 | — | — |
| W % | ≤ 1.5 | ≤ 1.0 | 3 – 4.5 | 2.5 – 3.5 |
| Carbon | ≤ 0.015% | ≤ 0.02% | ≤ 0.010% | ≤ 0.015% |
| Best at | Phosphoric/sulfuric + weldability | Older G successor | Strong reducing acids | Broad oxidizing+reducing |
| Relative cost | Moderate | Obsolete | Higher | Highest |
Selection guide: Choose Hastelloy G-3 for phosphoric/sulfuric acid, mixed-acid, and FGD service where excellent weldability and a favorable cost balance matter. Choose C-276 or C-22 when service involves strong reducing acids (e.g., hydrochloric) or severe pitting/crevice attack that demands higher molybdenum/tungsten. G-2 is essentially superseded by G-3 for new designs.
Hastelloy G-3 (UNS N06985 / W.Nr 2.4619, EN NiCr22Mo7Cu) is a nickel-chromium-iron alloy with additions of molybdenum and copper. It is the upgraded successor to Hastelloy G-2, with ultra-low carbon and tighter control of silicon and other minor elements to improve weldability and resistance to heat-affected-zone (HAZ) corrosion. It resists both oxidizing and reducing chemicals and is especially suited to wet phosphoric acid, sulfuric acid, nitric acid, and flue-gas-desulfurization (FGD) service.
Limiting composition of Hastelloy G-3 (UNS N06985): Nickel balance; Chromium 21.0-23.5%; Iron 18.0-21.0%; Molybdenum 6.0-8.0%; Copper 1.5-2.5%; Cobalt ≤5.0%; Tungsten ≤1.5%; Niobium+Tantalum ≤0.50%; Manganese ≤1.0%; Silicon ≤1.0%; Carbon ≤0.015%; Phosphorus ≤0.04%; Sulfur ≤0.03%. The ultra-low carbon prevents sensitization and intergranular corrosion in the weld HAZ.
In the solution-annealed condition, Hastelloy G-3 typically meets a minimum tensile strength of 621 MPa (90 ksi) with typical values around 690 MPa, a minimum yield strength of 241 MPa (35 ksi) with typical values near 320 MPa, elongation of at least 45% (typically ~50%), and hardness not exceeding about 100 HRB. It is ductile, formable, and non-magnetic.
Hastelloy G-3 has a density of about 8.14 g/cm³ (0.294 lb/in³). Its melting range is approximately 1260-1343°C (2300-2450°F). The mean coefficient of thermal expansion is about 14.6 ×10⁻⁶/°C over 20-100°C (rising to ~15.1 ×10⁻⁶/°C at 600°C), thermal conductivity about 10.0 W/(m·K) at 25°C, and modulus of elasticity about 199 GPa. It is non-magnetic.
Hastelloy G-3 resists hot sulfuric acid, wet (dihydrate) phosphoric acid, contaminated/reducing nitric acid, mixed acid streams, fluosilicic and sulfate solutions, and hydrofluoric acid environments. Its chromium gives oxidizing-acid resistance while nickel, molybdenum, and copper provide reducing-acid resistance. It is widely used in flue-gas-desulfurization (FGD) scrubbers and in oxidizing-chloride and sour (H2S/CO2/Cl⁻) oil-and-gas service meeting NACE MR0175/ISO 15156.
G-3 is the improved, lower-carbon successor to G-2. By dropping carbon from ~0.05% to ≤0.015% and tightening silicon and other minor elements, G-3 greatly reduces intergranular and knife-line attack in the weld heat-affected zone and improves fabricability, while retaining (and in many acids exceeding) G-2's corrosion resistance. G-3 is generally the preferred choice for new equipment; G-2 is now largely obsolete.
C-276 and C-22 are higher-molybdenum, tungsten-containing Ni-Cr-Mo alloys with superior resistance to strong reducing acids (e.g., hydrochloric) and to localized pitting/crevice corrosion, but they lack G-3's copper and cost more. G-3 offers an excellent, lower-cost balance of oxidizing- and reducing-acid resistance plus outstanding weldability, making it ideal for phosphoric/sulfuric acid and FGD service where C-276/C-22 would be over-specified.
Yes. Hastelloy G-3 has excellent weldability by GTAW (TIG), GMAW (MIG), and SMAW using matching filler metals ERNiCrMo-12 (AWS A5.14) / ENiCrMo-12 (AWS A5.11), or over-alloyed fillers such as ERNiCrMo-10/ENiCrMo-10. The ultra-low carbon gives very low sensitivity to weld cracking and prevents HAZ sensitization, so post-weld heat treatment is normally not required. ASME welding group F-No. 44. Clean joints and inert shielding are essential.
Hastelloy G-3 is supplied in the solution-annealed condition (typically 1040-1090°C, rapid water quench or fast cool) and is not age-hardenable. Post-weld heat treatment is normally unnecessary because the alloy does not sensitize. For stress relief of cold-worked or thick welded fabrications, a low-temperature treatment around 430-480°C for 1-2 hours (air cool) may be used.
Primary applications are in chemical processing and pollution control: wet-process phosphoric acid evaporators, reactors, filters and heat exchangers; sulfuric acid recovery and pickling systems; mixed-acid and fertilizer (nitric-phosphoric-sulfuric) equipment; flue-gas-desulfurization (FGD) scrubbers, dampers, ducts and stack liners; and sour oil-and-gas tubulars and components meeting NACE MR0175. It is also used in pulp & paper and wet-process metallurgy.
Key standards: UNS N06985; W.Nr 2.4619 (EN NiCr22Mo7Cu); ASTM B581 (bar), B582 (plate/sheet/strip), B619 (welded pipe), B622 (seamless pipe & tube), B626 (welded tube), B366 (fittings) and the ASME SB equivalents; NACE MR0175 / ISO 15156 for sour service; GB NS3403; and welding consumables AWS A5.14 ERNiCrMo-12 / A5.11 ENiCrMo-12.
Hangbo Alloy Group supplies Hastelloy G-3 as plate, sheet and strip (ASTM B582), bar, rod and forgings (B581), seamless pipe and tube (B622), welded pipe and tube (B619/B626), butt-weld fittings and flanges (B366), and matching welding consumables (ERNiCrMo-12). All product forms are supplied solution-annealed with full EN 10204 3.1 material certification.
Hastelloy G-3 is a premium corrosion-resistant nickel alloy. Typical market pricing ranges from roughly $40-70/kg for plate, sheet, bar and pipe, depending on product form, thickness, certification, and current nickel/molybdenum market conditions. Lead times are typically 3-6 weeks for stock sizes and 8-14 weeks for custom-forged or certified lots. Hangbo Alloy Group is a global Hastelloy G-3 manufacturer and supplier — contact serena@hangboalloy.com for a competitive quote.
