Nickel Alloy Inconel 725 HF+A
Heat-treated state
UNS N07725
HF+A = hot finished / forged then directly aged
Cost-saving route for large forgings where controlled hot-work plus direct age gives 120 ksi class properties without a separate solution treatment.
Values for the HF+A condition
Other Inconel 725 tempers and conditions
Inconel 725 is listed in 5 conditions; see the grade overview at Inconel 725.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Soft supply condition for forming, machining of complex shapes or welding before final age hardening. | 400 | 830 | 50 | 210 HB | — |
STA-120Default STA 120 ksi | Standard oilfield sour-service condition (API 6ACRA / NACE MR0175, ≤43 HRC) for downhole tools, hangers and valve parts. | 890 | 1,240 | 25 | 35 HRC | — |
HF+AThis page Hot finished / forged then directly aged | Cost-saving route for large forgings where controlled hot-work plus direct age gives 120 ksi class properties without a separate solution treatment. | 965 | 1,275 | 22 | 37 HRC | 1.4 % IACS |
STA 150 ksi | Higher-strength aged condition for high-load fasteners, mandrels and setting components where 43 HRC max still applies. | 1,090 | 1,310 | 20 | 40 HRC | — |
Cold worked then aged | Maximum-strength small-section bar and fastener stock; hardness must still be capped for sour service qualification. | 1,200 | 1,400 | 15 | 43 HRC | — |
What is Inconel 725 HF+A?
Inconel 725 HF+A is Inconel 725 heat treated to HF+A — cost-saving route for large forgings where controlled hot-work plus direct age gives 120 ksi class properties without a separate solution treatment. Inconel 725 HF+A has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 22% and the elastic modulus is 204 GPa (29.6 Msi). Inconel 725 HF+A has a density of 8.31 g/cm³ (0.3 lb/in³), heavier than 51% of nickel alloy grades. It melts at 1,271°C (2,320 °F). STA-120 is the default condition FabDigit quotes; HF+A is available on request or by drawing note.
Advantages
- High strength — 965 MPa (140 ksi), better than 95% of nickel alloy grades
Limitations
- High embodied carbon — 18 kg CO₂/kg, worse than 98% of nickel alloy grades
Inconel 725 HF+A properties
Typical room-temperature values for Inconel 725 HF+A; 22 are specific to this condition. Other listed values are Inconel 725 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Inconel 725 HF+A has a density of 8.31 g/cm³ (0.3 lb/in³), heavier than 51% of nickel alloy grades. It melts at 1,271°C (2,320 °F).
Mechanical16
Inconel 725 HF+A has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 22% and the elastic modulus is 204 GPa (29.6 Msi).
Thermal6
Inconel 725 HF+A is rated for continuous service to 650°C (1,202 °F). It conducts heat at 10.8 W/m·K (6.24 BTU/hr·ft·°F), worse than 66% of nickel alloy grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical3
Inconel 725 HF+A conducts electricity at 1.4 % IACS, worse than 51% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (86/100), better than 77% of nickel alloy grades.
Sustainability4
Producing a kilogram of Inconel 725 HF+A takes about 250 MJ of energy and emits 18 kg of CO₂ — more than 97% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability6
Inconel 725 HF+A's machinability is not recommended (13/100, worse than 82% of nickel alloy grades); weldability fair (50/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Inconel 725 HF+A
Is Inconel 725 easy to machine?
Treat like aged 718 but tougher: rigid setup, positive-rake coated carbide or ceramic at low speed/heavy feed, flood high-pressure coolant, constant engagement to avoid work-hardened glaze; rough in the solution-annealed state whenever possible.
Can Inconel 725 be welded?
GTAW/GMAW with matching 725 or ERNiCrMo-3 (625) filler, low heat input, no preheat, interpass <150 °C; re-solution anneal and double age after welding to restore strength and sour-service hardness compliance.
Can Inconel 725 be formed, bent or molded?
Cold form only in the solution-annealed condition (springback high, expect frequent intermediate anneals); hot work 1010–1180 °C with finishing above ~980 °C, then solution treat and age.
What surface finishes work on Inconel 725?
Not anodizable; passivates naturally so no coating is needed — pickle/blast to remove age-hardening oxide, then grind/polish or shot-peen threads and seal areas for fatigue and SCC resistance.
Inconel 725 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 | 55 – 59 | 57 |
| Cr | 19 – 22.5 | 21 |
| Mo | 7 – 9.5 | 8 |
| NbNb+Ta; γ″ former | 2.75 – 4 | 3.5 |
| Ti | 1 – 1.7 | 1.5 |
| Al | ≤ 0.35 | 0.2 |
| Mn | ≤ 0.35 | 0.1 |
| Si | ≤ 0.2 | 0.1 |
| Cu | ≤ 0.2 | 0.05 |
| C | ≤ 0.03 | 0.01 |
| S | ≤ 0.01 | 0 |
| P | ≤ 0.02 | 0.01 |
| Febalance, typically ~7–10 % | balance | — |
Inconel 725 HF+A — frequently asked
What is Inconel 725 HF+A used for?
Inconel 725 HF+A is typically used for oil and gas downhole tools, high-strength sour-service fasteners, subsea wellhead and hanger components, valve stems and trim for sour wells, packers and landing nipples and instrument and completion tubular parts. In short: age-hardened 625 chemistry; NACE sour-service strength; hard to machine when aged.
What is the yield strength of Inconel 725 HF+A?
Inconel 725 HF+A has a typical yield strength of 965 MPa (140 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Inconel 725 HF+A easy to machine?
Not especially — machinability is rated not recommended (13/100, worse than 82% of nickel alloy grades). Treat like aged 718 but tougher: rigid setup, positive-rake coated carbide or ceramic at low speed/heavy feed, flood high-pressure coolant, constant engagement to avoid work-hardened glaze; rough in the solution-annealed state whenever possible.
Can Inconel 725 HF+A be welded?
With care — weldability is rated fair (50/100). GTAW/GMAW with matching 725 or ERNiCrMo-3 (625) filler, low heat input, no preheat, interpass <150 °C; re-solution anneal and double age after welding to restore strength and sour-service hardness compliance.
What surface finishes work on Inconel 725 HF+A?
Not anodizable; passivates naturally so no coating is needed — pickle/blast to remove age-hardening oxide, then grind/polish or shot-peen threads and seal areas for fatigue and SCC resistance.
Can Inconel 725 HF+A be formed, bent or molded?
Cold form only in the solution-annealed condition (springback high, expect frequent intermediate anneals); hot work 1010–1180 °C with finishing above ~980 °C, then solution treat and age.
What is the maximum service temperature of Inconel 725 HF+A?
Inconel 725 HF+A is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Inconel 725 STA-120 and Inconel 725-SA?
STA-120 is the default condition — standard oilfield sour-service condition (API 6ACRA / NACE MR0175, ≤43 HRC) for downhole tools, hangers and valve parts. SA: soft supply condition for forming, machining of complex shapes or welding before final age hardening. Yield strength is 890 MPa in STA-120 versus 400 MPa in SA.
Sources
- INCONEL alloy 725 datasheet — Special Metals Corporation (2004)
- API 6ACRA — Age-Hardened Nickel-Based Alloys for Oil and Gas Drilling and Production Equipment — API (2020)
- ANSI/NACE MR0175 / ISO 15156-3 — Cracking-resistant CRAs for H2S service — NACE/ISO (2020)
- ASTM B637 — Precipitation-Hardening Nickel Alloy Bars, Forgings and Forging Stock — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
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.