Nickel Alloy Hastelloy G-2-HFA (Hot Finished and Annealed)
Heat-treated state
UNS N06975
Pick hot finished and annealed heavy plate, forgings and large-diameter bar for pressure-vessel heads and flanges; coarser grain lowers yield to 280 MPa but keeps 50% elongation.
Values for the HFA condition
Other Hastelloy G-2 tempers and conditions
Hastelloy G-2 is listed in 5 conditions; see the grade overview at Hastelloy G-2.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HFAThis page Hot Finished and Annealed | Pick hot finished and annealed heavy plate, forgings and large-diameter bar for pressure-vessel heads and flanges; coarser grain lowers yield to 280 MPa but keeps 50% elongation. | 280 | 635 | 50 | 183 HB | 1.4 % IACS |
SADefault Solution Annealed | Choose mill solution annealed and water quenched sheet, strip, tube or bar for the best corrosion resistance and toughness (295 MPa yield, 48% elongation); the default for chemical equipment. | 295 | 655 | 48 | 190 HB | — |
As-welded deposit | Use to evaluate weld joint properties; as-welded strength approaches the annealed base metal, but weld dendritic segregation lowers the corrosion margin, so solution treat after welding for severe service. | 340 | 640 | 35 | 200 HB | 1.4 % IACS |
Cold drawn | Choose for fasteners, valve stems and pump shafts needing 550 MPa yield with tight dimensional accuracy; control the cold-drawing residual stress with a stress-relief treatment. | 550 | 790 | 28 | 22 HRC | 1.4 % IACS |
Cold Worked / Hard strip and tube | Pick for spring elements and thin-wall high-pressure tubing needing 720 MPa yield; ductility falls to 12% and intergranular corrosion margin drops, so solution treat after forming. | 720 | 930 | 12 | 28 HRC | 1.4 % IACS |
What is Hastelloy G-2-HFA?
Hastelloy G-2-HFA is Hastelloy G-2 heat treated to HFA — pick hot finished and annealed heavy plate, forgings and large-diameter bar for pressure-vessel heads and flanges; coarser grain lowers yield to 280 MPa but keeps 50% elongation. Hastelloy G-2-HFA has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 82% of nickel alloy grades. Elongation at break is 50% and the elastic modulus is 199 GPa (28.9 Msi). Hastelloy G-2-HFA has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,330°C (2,426 °F). SA is the default condition FabDigit quotes; HFA is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 50%, better than 88% of nickel alloy grades
Limitations
- Low strength — 280 MPa (40.6 ksi), worse than 82% of nickel alloy grades
- Limited service temperature — 540°C (1,004 °F), worse than 75% of nickel alloy grades
Hastelloy G-2-HFA properties
Typical room-temperature values for Hastelloy G-2-HFA; 21 are specific to this condition. Other listed values are Hastelloy G-2 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Hastelloy G-2-HFA has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,330°C (2,426 °F).
Mechanical13
Hastelloy G-2-HFA has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 82% of nickel alloy grades. Elongation at break is 50% and the elastic modulus is 199 GPa (28.9 Msi).
Thermal6
Hastelloy G-2-HFA is rated for continuous service to 540°C (1,004 °F). It conducts heat at 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 73% of nickel alloy grades. Thermal expansion is 13.6 µm/m·K (7.56 µin/in·°F).
Electrical3
Hastelloy G-2-HFA conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (81/100), better than 65% of nickel alloy grades.
Sustainability4
Producing a kilogram of Hastelloy G-2-HFA takes about 150 MJ of energy and emits 12 kg of CO₂ — less than 68% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability8
Hastelloy G-2-HFA's machinability is poor (22/100, better than 64% of nickel alloy grades); weldability very good (72/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Hastelloy G-2-HFA
Is Hastelloy G-2 easy to machine?
Handle as a nickel corrosion alloy: low speed with heavy feed, rigid clamping, sharp positive-rake tooling (K/M-grade carbide) and generous emulsion coolant to prevent rubbing that builds a work-hardened layer.
Can Hastelloy G-2 be welded?
Mainly GTAW and GMAW using matching filler or ERNiCrMo-1 (Alloy G-3). Keep heat input low and interpass temperature below 100 °C, no preheat required; a post-weld solution treatment can be used for severe corrosion service.
Can Hastelloy G-2 be formed, bent or molded?
Ductile in the annealed condition for cold pressing, plate rolling and tube expanding, but the work-hardening rate is high, so deep forming needs intermediate anneals at about 1120 °C followed by water quench. Hot work at roughly 900–1180 °C.
What surface finishes work on Hastelloy G-2?
Not suitable for anodizing. Remove scale by nitric-hydrofluoric pickling and then passivate, or mechanically polish / electropolish to a low roughness to improve pitting resistance.
Hastelloy G-2 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ni | 47 – 52 | 49.5 |
| Cr | 23 – 26 | 24.5 |
| Mo | 5 – 7 | 6 |
| Cuimproves corrosion resistance in reducing acids | 0.7 – 1.2 | 0.9 |
| Tistabilizer, suppresses intergranular corrosion | 0.7 – 1.5 | 1 |
| C | ≤ 0.03 | 0.02 |
| Mn | ≤ 1 | 0.5 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Febalance, typically 15–20% | balance | — |
Hastelloy G-2-HFA — frequently asked
What is Hastelloy G-2-HFA used for?
Hastelloy G-2-HFA is typically used for sulfuric acid alkylation units, mixed acid service, chemical process vessels and acid coolers. In short: mixed nitric-sulfuric acid grade; cu-bearing Ni-Cr-Mo alloy; 540 °C service limit.
What is the yield strength of Hastelloy G-2-HFA?
Hastelloy G-2-HFA has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 82% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Hastelloy G-2-HFA easy to machine?
Not especially — machinability is rated poor (22/100, better than 64% of nickel alloy grades). Handle as a nickel corrosion alloy: low speed with heavy feed, rigid clamping, sharp positive-rake tooling (K/M-grade carbide) and generous emulsion coolant to prevent rubbing that builds a work-hardened layer.
Can Hastelloy G-2-HFA be welded?
Yes — weldability is rated very good (72/100). Mainly GTAW and GMAW using matching filler or ERNiCrMo-1 (Alloy G-3). Keep heat input low and interpass temperature below 100 °C, no preheat required; a post-weld solution treatment can be used for severe corrosion service.
What surface finishes work on Hastelloy G-2-HFA?
Not suitable for anodizing. Remove scale by nitric-hydrofluoric pickling and then passivate, or mechanically polish / electropolish to a low roughness to improve pitting resistance.
Can Hastelloy G-2-HFA be formed, bent or molded?
Ductile in the annealed condition for cold pressing, plate rolling and tube expanding, but the work-hardening rate is high, so deep forming needs intermediate anneals at about 1120 °C followed by water quench. Hot work at roughly 900–1180 °C.
What is the maximum service temperature of Hastelloy G-2-HFA?
Hastelloy G-2-HFA is rated for continuous use to about 540°C (1,004 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Hastelloy G-2-SA and Hastelloy G-2 CW-H?
SA is the default condition — choose mill solution annealed and water quenched sheet, strip, tube or bar for the best corrosion resistance and toughness (295 MPa yield, 48% elongation); the default for chemical equipment. CW-H: pick for spring elements and thin-wall high-pressure tubing needing 720 MPa yield; ductility falls to 12% and intergranular corrosion margin drops, so solution treat after forming. Yield strength is 295 MPa in SA versus 720 MPa in CW-H.
Sources
- ASTM B582 — Ni-Cr-Fe-Mo-Cu Alloy Plate, Sheet and Strip (N06975) — ASTM International (2019)
- ASTM B581 — Ni-Cr-Fe-Mo-Cu Alloy Rod and Bar (N06975) — ASTM International (2019)
- ASTM B622 / B626 — Seamless and Welded Ni-Alloy Pipe and Tube — ASTM International (2022)
- HASTELLOY G-series Alloys (G, G-2, G-3, G-30) technical data — Haynes International (2020)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.