Nickel Alloy Alloy 689-HF (As-hot-worked / as-forged)
Grade
UNS N07252
Intermediate mill product supplied for further forging or re-heat-treatment; properties not guaranteed.
Values for the HF condition
Other Alloy 689 tempers and conditions
Alloy 689 is listed in 5 conditions; see the grade overview at Alloy 689.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supplied condition for machining, forming or welding before the ageing treatment. | 585 | 965 | 32 | 22 HRC | — |
HFThis page As-hot-worked / as-forged | Intermediate mill product supplied for further forging or re-heat-treatment; properties not guaranteed. | 690 | 1,050 | 24 | 28 HRC | 1.5 % IACS |
Double aged | Stabilising intermediate age before the final age; chosen for long-time creep and rupture ductility at 700–815 °C. | 820 | 1,200 | 18 | 34 HRC | 1.5 % IACS |
STADefault Solution treated and aged | Standard fully heat-treated condition for turbine discs, shafts and bolting up to ~815 °C. | 840 | 1,240 | 16 | 35 HRC | — |
Low-temperature solution (≈1010 °C) + 760 °C age | Finer grain, higher room- and intermediate-temperature strength; use where tensile/LCF strength matters more than creep-rupture life. | 900 | 1,310 | 18 | 37 HRC | 1.4 % IACS |
What is Alloy 689-HF?
Alloy 689-HF is Alloy 689 in the HF grade — intermediate mill product supplied for further forging or re-heat-treatment; properties not guaranteed. Alloy 689-HF has a yield strength of 690 MPa (100 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi). Alloy 689-HF has a density of 8.27 g/cm³ (0.299 lb/in³), lighter than 56% of nickel alloy grades. It melts at 1,315°C (2,399 °F). STA is the default condition FabDigit quotes; HF is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 81% of nickel alloy grades
Limitations
- High embodied carbon — 15 kg CO₂/kg, worse than 87% of nickel alloy grades
- Needs corrosion protection — 68/100, worse than 82% of nickel alloy grades
Alloy 689-HF properties
Typical room-temperature values for Alloy 689-HF; 22 are specific to this condition. Other listed values are Alloy 689 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Alloy 689-HF has a density of 8.27 g/cm³ (0.299 lb/in³), lighter than 56% of nickel alloy grades. It melts at 1,315°C (2,399 °F).
Mechanical14
Alloy 689-HF has a yield strength of 690 MPa (100 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Alloy 689-HF is rated for continuous service to 650°C (1,202 °F). It conducts heat at 12.1 W/m·K (6.99 BTU/hr·ft·°F), better than 68% of nickel alloy grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
Alloy 689-HF conducts electricity at 1.5 % IACS, better than 52% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), worse than 82% of nickel alloy grades.
Sustainability4
Producing a kilogram of Alloy 689-HF takes about 230 MJ of energy and emits 15 kg of CO₂ — more than 91% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
Alloy 689-HF's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability fair (45/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 689-HF
Is Alloy 689 easy to machine?
Machine in the solution-annealed condition where possible; rigid setups, positive-rake carbide or ceramic tools, low speed / heavy feed and flood coolant, and expect grinding or EDM for finishing after ageing.
Can Alloy 689 be welded?
GTAW with matched or Ni-Cr-Co filler on solution-annealed material only, low heat input, followed by full re-solution and age — the ~3.6 % Ti+Al makes it prone to strain-age cracking on reheating.
Can Alloy 689 be formed, bent or molded?
Hot work at roughly 1050–1180 °C with generous reheats; cold forming is limited to mild bends in the annealed state because of very high work-hardening rate.
What surface finishes work on Alloy 689?
Grit blast plus pickle or vacuum-clean before brazing/coating; shot peening is standard for fatigue life, and aluminide or MCrAlY coatings are used for hot-gas surfaces — anodizing does not apply.
Alloy 689 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 |
|---|---|---|
| Ccarbide former for grain-boundary strength | 0.1 – 0.2 | 0.15 |
| Cr | 18 – 20 | 19 |
| Co | 9 – 11 | 10 |
| Mosolid-solution strengthener | 9 – 10.5 | 10 |
| Tiγ′ former | 2.25 – 2.75 | 2.6 |
| Alγ′ former | 0.75 – 1.25 | 1 |
| Fe | ≤ 2 | 1 |
| Mn | ≤ 0.5 | — |
| Si | ≤ 0.5 | — |
| Bgrain-boundary creep resistance | 0 – 0.01 | 0.01 |
| S | ≤ 0.02 | — |
| P | ≤ 0.02 | — |
| Nibalance, nominally ~56 % | balance | — |
Alloy 689-HF — frequently asked
What is Alloy 689-HF used for?
Alloy 689-HF is typically used for precision high-temperature fixtures, instrumentation components in hot zones, high-temperature bolting, turbine hardware forgings, heat-treat and brazing jigs and dimensionally critical hot-section brackets. In short: dimensional stability at 815 °C; aged strength near 1240 MPa; strain-age cracking sensitive.
What is the yield strength of Alloy 689-HF?
Alloy 689-HF has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 81% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 689-HF easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% of nickel alloy grades). Machine in the solution-annealed condition where possible; rigid setups, positive-rake carbide or ceramic tools, low speed / heavy feed and flood coolant, and expect grinding or EDM for finishing after ageing.
Can Alloy 689-HF be welded?
With care — weldability is rated fair (45/100). GTAW with matched or Ni-Cr-Co filler on solution-annealed material only, low heat input, followed by full re-solution and age — the ~3.6 % Ti+Al makes it prone to strain-age cracking on reheating.
What surface finishes work on Alloy 689-HF?
Grit blast plus pickle or vacuum-clean before brazing/coating; shot peening is standard for fatigue life, and aluminide or MCrAlY coatings are used for hot-gas surfaces — anodizing does not apply.
Can Alloy 689-HF be formed, bent or molded?
Hot work at roughly 1050–1180 °C with generous reheats; cold forming is limited to mild bends in the annealed state because of very high work-hardening rate.
What is the maximum service temperature of Alloy 689-HF?
Alloy 689-HF 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 Alloy 689-STA and Alloy 689-SA?
STA is the default condition — standard fully heat-treated condition for turbine discs, shafts and bolting up to ~815 °C. SA: softest supplied condition for machining, forming or welding before the ageing treatment. Yield strength is 840 MPa in STA versus 585 MPa in SA.
Sources
- ASM Specialty Handbook: Heat-Resistant Materials — ASM International (1997)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Superalloys II (Sims, Stoloff, Hagel) — Wiley (1987)
- ASTM B637 — Precipitation-Hardening Nickel Alloy Bars, Forgings and Forging Stock for High-Temperature Service — ASTM International (2018)
- UNS N07252 alloy designation record — SAE/ASTM Unified Numbering System (2020)
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.