Nickel Alloy Inconel 690
UNS N06690 · EN 2.4642, NiCr29Fe
Inconel 690 (UNS N06690, 2.4642, NiCr29Fe) is a solid-solution nickel-chromium alloy of the 600 family whose higher chromium content gives markedly better resistance to stress-corrosion cracking in high-purity, high-temperature water.
Reference datasheet — Inconel 690 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 ANN condition
Inconel 690 tempers and conditions
Inconel 690 is supplied in 7 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Thermally treated | Nuclear steam-generator tubing condition (Alloy 690TT) giving maximum resistance to primary-water and caustic SCC. | 320 | 700 | 45 | 165 HB | — |
ANNDefault Annealed | Standard stocked condition for plate, sheet, bar and tube — best ductility, formability and corrosion resistance. | 345 | 725 | 45 | 170 HB | — |
Hot worked / hot finished | Economical condition for heavy bar, forgings and rings where the hot-finished properties satisfy ASTM B166 minima. | 400 | 760 | 38 | 190 HB | — |
Quarter-Hard | Light cold work for slightly higher yield strength while keeping useful bending ductility in strip and tube. | 550 | 800 | 28 | 17 HRC | 1.5 % IACS |
Cold drawn + stress relieved | Cold-drawn bar/tube with residual stresses reduced for dimensional stability and lower SCC risk while keeping most cold-work strength. | 690 | 880 | 20 | 22 HRC | 1.5 % IACS |
Half-Hard | Springy strip, wire and thin-wall tube needing roughly double the annealed yield strength. | 700 | 900 | 18 | 24 HRC | — |
Full-Hard | Maximum as-drawn strength for springs, fasteners and small-diameter wire; very limited ductility and no recrystallization above ~550 °C service. | 900 | 1,070 | 8 | 32 HRC | — |
What is Inconel 690?
Inconel 690 (UNS N06690, 2.4642, NiCr29Fe) is a solid-solution nickel-chromium alloy of the 600 family whose higher chromium content gives markedly better resistance to stress-corrosion cracking in high-purity, high-temperature water. It is the standard material for nuclear steam generator tubing and primary-circuit components, available annealed, thermally treated, hot-worked, cold-worked to 1/4, 1/2 and full hard, or cold-drawn and stress-relieved, with 345 MPa yield, 725 MPa tensile, 45 % elongation, 170 HB, 211 GPa modulus and service to 1050 °C. Weldability (78) and formability (70) are good; machinability is the limitation at 25. Inconel 690 has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,343°C (2,449 °F). Inconel 690 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 62% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 211 GPa (30.6 Msi).
What is Inconel 690 used for?
- Nuclear steam generator tubing
- Pressurised water reactor primary-side components
- Reactor vessel head penetrations and nozzles
- Tube plugs and sleeves
- Nuclear waste vitrification melter parts
- Nitric and mixed-acid process equipment
- High-temperature furnace and process hardware
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 99% of nickel alloy grades
- High service temperature — 1,050°C (1,922 °F), better than 83% of nickel alloy grades
- Good corrosion resistance — 88/100, better than 81% of nickel alloy grades
Inconel 690 properties
Typical room-temperature values for Inconel 690-ANN; bars are the position among nickel alloy grades.
Physical3
Inconel 690 has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,343°C (2,449 °F).
Mechanical16
Inconel 690 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 62% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
Inconel 690 is rated for continuous service to 1,050°C (1,922 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), better than 73% of nickel alloy grades. Thermal expansion is 14 µm/m·K (7.78 µin/in·°F).
Electrical3
Inconel 690 conducts electricity at 1.5 % IACS, better than 59% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 81% of nickel alloy grades.
Sustainability4
Producing a kilogram of Inconel 690 takes about 135 MJ of energy and emits 13.5 kg of CO₂ — less than 84% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
Inconel 690's machinability is poor (25/100, better than 76% of nickel alloy grades); weldability very good (78/100); 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. Inconel 690 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Inconel 690
Is Inconel 690 easy to machine?
Treat like a gummy austenitic superalloy: rigid setups, positive-rake sharp carbide or ceramic tools, heavy constant feed to cut under the work-hardened layer, low SFM and copious high-pressure coolant.
Can Inconel 690 be welded?
Readily GTAW/GMAW/SMAW welded without preheat or PWHT; use matching ERNiCrFe-7/7A or ERNiCr-3 style high-Cr fillers, keep interpass temperature low and heat input modest to avoid hot cracking.
Can Inconel 690 be formed, bent or molded?
Cold forms well in the annealed temper but work-hardens fast — allow extra power, generous radii and intermediate anneals at 1040–1090 °C; hot work at 1090–1230 °C with finishing above ~950 °C.
Inconel 690 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 |
|---|---|---|
| Ni58 % minimum per ASTM B168 | ≥ 58 | 60 |
| Cr | 27 – 31 | 29 |
| Fe | 7 – 11 | 9.5 |
| C0.015–0.025 typical for TT nuclear tubing | ≤ 0.05 | 0.02 |
| Mn | ≤ 0.5 | 0.2 |
| Si | ≤ 0.5 | 0.3 |
| Cu | ≤ 0.5 | 0.02 |
| S | ≤ 0.02 | 0 |
| Tispecified in nuclear tubing orders | ≤ 0.5 | 0.25 |
| Alsupplementary/producer limit | ≤ 0.5 | 0.2 |
What surface finishes work on Inconel 690?
Pickle or grind off the tenacious chromium oxide before welding and before any brazing/plating; electropolishing or fine mechanical polishing gives the low-crud surfaces required for nuclear 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 Inconel 690 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N06690
- EN / DIN / Werkstoff-Nr.
- 2.4642NiCr29Fe
How much does Inconel 690 cost?
Inconel 690 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.
Inconel 690 — frequently asked
What is Inconel 690 used for?
Inconel 690 is typically used for nuclear steam generator tubing, pressurised water reactor primary-side components, reactor vessel head penetrations and nozzles, tube plugs and sleeves, nuclear waste vitrification melter parts and nitric and mixed-acid process equipment. In short: nuclear-grade SCC resistance; high-Cr upgrade of Alloy 600; good weldability, poor machinability.
What is the yield strength of Inconel 690?
Inconel 690 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 62% of nickel alloy grades. Strength varies by condition: see the 7 listed tempers.
Is Inconel 690 easy to machine?
Not especially — machinability is rated poor (25/100, better than 76% of nickel alloy grades). Treat like a gummy austenitic superalloy: rigid setups, positive-rake sharp carbide or ceramic tools, heavy constant feed to cut under the work-hardened layer, low SFM and copious high-pressure coolant.
Can Inconel 690 be welded?
Yes — weldability is rated very good (78/100). Readily GTAW/GMAW/SMAW welded without preheat or PWHT; use matching ERNiCrFe-7/7A or ERNiCr-3 style high-Cr fillers, keep interpass temperature low and heat input modest to avoid hot cracking.
What surface finishes work on Inconel 690?
Pickle or grind off the tenacious chromium oxide before welding and before any brazing/plating; electropolishing or fine mechanical polishing gives the low-crud surfaces required for nuclear service.
Can Inconel 690 be formed, bent or molded?
Cold forms well in the annealed temper but work-hardens fast — allow extra power, generous radii and intermediate anneals at 1040–1090 °C; hot work at 1090–1230 °C with finishing above ~950 °C.
What is the maximum service temperature of Inconel 690?
Inconel 690 is rated for continuous use to about 1,050°C (1,922 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Inconel 690-ANN and Inconel 690 CW-FH?
ANN is the default condition — standard stocked condition for plate, sheet, bar and tube — best ductility, formability and corrosion resistance. CW-FH: maximum as-drawn strength for springs, fasteners and small-diameter wire; very limited ductility and no recrystallization above ~550 °C service. Yield strength is 345 MPa in ANN versus 900 MPa in CW-FH.
How much does Inconel 690 cost?
Inconel 690 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
- INCONEL alloy 690 technical bulletin — Special Metals Corporation (2009)
- ASTM B168 — Ni-Cr-Fe alloy plate, sheet and strip — ASTM International (2019)
- ASTM B166 — Ni-Cr-Fe alloy rod, bar and wire — ASTM International (2019)
- ASME SB-163 / SB-167 (N06690 tubing, incl. thermally treated) — ASME (2021)
- GB/T 15007 / NS3105 (2017)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — 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.