Nickel Alloy Alloy 686
UNS N06686, N06058 · EN 2.4606 · also Inconel 686
Alloy 686 is a Ni-Cr-Mo-W corrosion-resistant alloy (UNS N06686 / N06058, 2.4606, also sold as Inconel 686) supplied annealed, hot-finished annealed, cold-drawn, cold-worked or as-welded.
Reference datasheet — Alloy 686 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
Alloy 686 tempers and conditions
Alloy 686 is supplied in 5 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
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?
Alloy 686 is a Ni-Cr-Mo-W corrosion-resistant alloy (UNS N06686 / N06058, 2.4606, also sold as Inconel 686) supplied annealed, hot-finished annealed, cold-drawn, cold-worked or as-welded. It is specified for severe chloride and acidic service — scrubbers, chemical process piping and vessels, plate, sheet, tube and weld wire — with a corrosion resistance score of 95 and typical annealed properties of 380 MPa yield, 760 MPa tensile, 60 % elongation, 190 HB and service to 1000 °C. Machinability is low (score 18) and the alloy is expensive; C-276 is the usual step down when the extra pitting and crevice margin is not needed. Alloy 686 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). Alloy 686 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 53% of nickel alloy grades. Elongation at break is 60% and the elastic modulus is 208 GPa (30.2 Msi).
What is Alloy 686 used for?
- scrubber systems
- chemical process equipment
- pollution control hardware
Advantages
- Ductile — tolerates forming and impact — 60%, better than 98% of nickel alloy grades
- Good corrosion resistance — 95/100, better than 97% 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 properties
Typical room-temperature values for Alloy 686-Annealed; bars are the position among nickel alloy grades.
Physical3
Alloy 686 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 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 53% of nickel alloy grades. Elongation at break is 60% and the elastic modulus is 208 GPa (30.2 Msi).
Thermal6
Alloy 686 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 conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 97% of nickel alloy grades.
Sustainability4
Producing a kilogram of Alloy 686 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's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability very good (80/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. Alloy 686 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Alloy 686
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.
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 |
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.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Nickel Alloy Alloy 686 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N06686N06058
- EN / DIN / Werkstoff-Nr.
- 2.4606
- Trade names
- Inconel 686
How much does Alloy 686 cost?
Alloy 686 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Alloy 686 — frequently asked
What is Alloy 686 used for?
Alloy 686 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?
Alloy 686 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 53% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 686 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 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?
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 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?
Alloy 686 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.
How much does Alloy 686 cost?
Alloy 686 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.