Nickel Alloy Alloy 686 HF-ANN
Finish state
UNS N06686, N06058 · EN 2.4606 · also Inconel 686
HF-ANN = hot Finished + Annealed
Choose for heavy sections, forged flanges and thick plate where hot working is followed by a mill anneal.
Values for the HF-ANN condition
Other Alloy 686 tempers and conditions
Alloy 686 is listed in 5 conditions; see the grade overview at Alloy 686.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HF-ANNThis page Hot Finished + Annealed | Choose for heavy sections, forged flanges and thick plate where hot working is followed by a mill anneal. | 370 | 750 | 55 | 13 HRC | 1.4 % IACS |
AnnealedDefault mill/solution annealed (1120–1180 °C, rapid quench) | Standard stocked condition for plate, sheet, pipe and forgings — maximum corrosion resistance and ductility for forming and welding. | 380 | 760 | 60 | 190 HB | — |
As-welded deposit | Data for matching filler weld metal and weld overlay/cladding used on carbon or stainless substrates in scrubber and chemical service. | 480 | 760 | 40 | 14 HRC | 1.4 % IACS |
Cold drawn | Use for fasteners, shafts, instrument tubing and pump parts needing higher yield strength and tight tolerances. | 620 | 900 | 30 | 25 HRC | — |
Cold Worked | Springs, clips, bellows and thin strip where maximum strength matters more than formability or absolute corrosion margin. | 830 | 1,030 | 15 | 32 HRC | 1.4 % IACS |
What is Alloy 686 HF-ANN?
Alloy 686 HF-ANN is Alloy 686 supplied in the HF-ANN condition — choose for heavy sections, forged flanges and thick plate where hot working is followed by a mill anneal. Alloy 686 HF-ANN has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 55% of nickel alloy grades. Elongation at break is 55% and the elastic modulus is 207 GPa (30 Msi). Alloy 686 HF-ANN has a density of 8.73 g/cm³ (0.315 lb/in³), heavier than 77% of nickel alloy grades. It melts at 1,338°C (2,440 °F). Annealed is the default condition FabDigit quotes; HF-ANN is available on request or by drawing note.
Advantages
- Good corrosion resistance — 94/100, better than 97% of nickel alloy grades
- Ductile — tolerates forming and impact — 55%, better than 93% of nickel alloy grades
- High service temperature — 1,000°C (1,832 °F), better than 79% of nickel alloy grades
Limitations
- Poor heat conductor — 9.1 W/m·K (5.26 BTU/hr·ft·°F), worse than 95% of nickel alloy grades
Alloy 686 HF-ANN properties
Typical room-temperature values for Alloy 686 HF-ANN; 23 are specific to this condition. Other listed values are Alloy 686 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Alloy 686 HF-ANN has a density of 8.73 g/cm³ (0.315 lb/in³), heavier than 77% of nickel alloy grades. It melts at 1,338°C (2,440 °F).
Mechanical15
Alloy 686 HF-ANN has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 55% of nickel alloy grades. Elongation at break is 55% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
Alloy 686 HF-ANN is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 9.1 W/m·K (5.26 BTU/hr·ft·°F), worse than 95% of nickel alloy grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
Alloy 686 HF-ANN conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (94/100), better than 97% of nickel alloy grades.
Sustainability4
Producing a kilogram of Alloy 686 HF-ANN takes about 150 MJ of energy and emits 12.5 kg of CO₂ — less than 68% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability8
Alloy 686 HF-ANN's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability very good (80/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 686 HF-ANN
Is Alloy 686 easy to machine?
Machine like C-276: rigid setups, positive-rake carbide, low speed / heavy feed, flood coolant and no dwelling to avoid rapid work hardening and glazing.
Can Alloy 686 be welded?
Excellent GTAW/GMAW/SMAW weldability with matching ERNiCrMo-14 filler; keep heat input and interpass temperature low, no preheat or PWHT required, clean to bright metal between passes.
Can Alloy 686 be formed, bent or molded?
Cold forms well but needs ~1.5–2× the force of 304 and frequent intermediate anneals at 1120–1180 °C with rapid cooling; hot work 900–1200 °C then anneal and quench.
What surface finishes work on Alloy 686?
Not anodizable — pickle in HNO₃-HF or grind/blast to remove heat tint, then passivate; electropolishing gives best pitting resistance for high-purity service.
Alloy 686 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 |
|---|---|---|
| Cr | 19 – 23 | 20.5 |
| Mo | 15 – 17 | 16.3 |
| W | 3 – 4.4 | 3.8 |
| Fetypically kept low | ≤ 5 | 1.5 |
| Tistabiliser | 0.02 – 0.25 | 0.05 |
| C | ≤ 0.01 | 0.01 |
| Mn | ≤ 0.75 | 0.25 |
| Si | ≤ 0.08 | 0.04 |
| Al | ≤ 0.5 | 0.2 |
| P | ≤ 0.04 | — |
| S | ≤ 0.02 | — |
| Cuproducer limit | ≤ 0.5 | — |
| Coproducer/nuclear-grade limit | ≤ 0.5 | — |
| Niremainder, ≈55–58 % | balance | — |
Alloy 686 HF-ANN — frequently asked
What is Alloy 686 HF-ANN used for?
Alloy 686 HF-ANN is typically used for scrubber systems, chemical process equipment and pollution control hardware. In short: top-tier pitting resistance; better than C-276 in chlorides; fully weldable, no PWHT.
What is the yield strength of Alloy 686 HF-ANN?
Alloy 686 HF-ANN has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 55% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 686 HF-ANN easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% of nickel alloy grades). Machine like C-276: rigid setups, positive-rake carbide, low speed / heavy feed, flood coolant and no dwelling to avoid rapid work hardening and glazing.
Can Alloy 686 HF-ANN be welded?
Yes — weldability is rated very good (80/100). Excellent GTAW/GMAW/SMAW weldability with matching ERNiCrMo-14 filler; keep heat input and interpass temperature low, no preheat or PWHT required, clean to bright metal between passes.
What surface finishes work on Alloy 686 HF-ANN?
Not anodizable — pickle in HNO₃-HF or grind/blast to remove heat tint, then passivate; electropolishing gives best pitting resistance for high-purity service.
Can Alloy 686 HF-ANN be formed, bent or molded?
Cold forms well but needs ~1.5–2× the force of 304 and frequent intermediate anneals at 1120–1180 °C with rapid cooling; hot work 900–1200 °C then anneal and quench.
What is the maximum service temperature of Alloy 686 HF-ANN?
Alloy 686 HF-ANN is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Alloy 686 Annealed and Alloy 686 CW-Hard?
Annealed is the default condition — standard stocked condition for plate, sheet, pipe and forgings — maximum corrosion resistance and ductility for forming and welding. CW-Hard: springs, clips, bellows and thin strip where maximum strength matters more than formability or absolute corrosion margin. Yield strength is 380 MPa in Annealed versus 830 MPa in CW-Hard.
Sources
- ASTM B575 — Ni-Cr-Mo alloy plate, sheet and strip (UNS N06686) — ASTM International (2022)
- ASTM B574 / B622 / B619 — rod, bar, seamless and welded pipe (N06686) — ASTM International (2021)
- INCONEL alloy 686 technical bulletin — Special Metals Corporation (2020)
- VDM Alloy 686 (2.4606) material data sheet — VDM Metals (2021)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (corrosion-resistant Ni 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.