Inconel 706 (UNS N09706) - Large Forging Superalloy Supplier of Bars, Forgings & Rings | Shanghai Hangbo Alloy Group
Date: 2026年8月11日 Categories: News Views: 317
By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012
Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360
Quick Answer: What Is Inconel 706?
Inconel 706 (UNS N09706 / W.Nr. 2.4614) is a precipitation-hardenable nickel-iron-chromium superalloy designed specifically for large turbine and generator discs where Inconel 718's niobium-rich segregation becomes unacceptable. With 42% nickel, 16% chromium, and a Fe + Nb + Ti + Al balance, it provides 718-class strength with dramatically better forgeability and reduced segregation in sections over 300 mm thick — the standard material for land-based gas turbine and generator rotor discs. Shanghai Hangbo Alloy Group supplies Inconel 706 as round bars, forgings, and rings.
Industry Pain Point: Land-based power turbine discs weighing 5-20 tonnes exceed the solidification limits where Inconel 718 remains sound — niobium-rich Laves-phase segregation at the center of large ingots causes rejected discs and catastrophic fatigue failures. Inconel 706 was developed by Special Metals to solve this: by reducing niobium (2.9% vs 5.2%) and raising iron (~37% vs 19%), the alloy's segregation tendency is dramatically suppressed, allowing sound forgings up to 1,200 mm diameter that are impossible in 718.
Key Properties at a Glance
| Property | Value |
|---|---|
| UNS Number | N09706 |
| W.Nr. | 2.4614 |
| Density | 8.08 g/cm3 |
| Melting Range | 1320-1375C |
| Tensile (Aged) | >= 1000 MPa (145 ksi) |
| Yield (Aged) | >= 700 MPa (102 ksi) |
| Elongation (Aged) | >= 15% |
| Key Standards | AMS 5701, ASTM B637, API 6A718 compatible |
Product Overview
Inconel 706 is the answer to a manufacturing physics problem: how to produce sound ultra-large superalloy forgings. The alloy achieves 718-class mechanical properties through the same γ″ (Ni₃Nb) + γ′ (Ni₃Ti/Al) precipitation mechanism, but with a composition engineered for large-section forgeability:
- Niobium reduced to 2.9% (vs 5.2% in 718): Niobium is the primary segregation culprit. Halving it eliminates the Laves-phase and δ-phase channel segregation that destroys 718 ingots above ~500 mm diameter.
- Iron raised to ~37%: Iron dilutes the segregation-driving elements and reduces ingot cost.
- γ″-to-γ′ ratio adjusted: More γ′ (titanium-rich) relative to γ″ produces slower aging response with wider process windows — ideal for thick sections where uniform aging is difficult.
The result is an alloy that forgers can produce as sound discs to 1,200+ mm diameter, with a room-temperature strength within 5-10% of 718 and equivalent corrosion resistance.
Shanghai Hangbo Alloy Group supplies Inconel 706 in bars (for smaller components), forged discs and rings (for turbine rotors), and billets.
Executive Standards
| Product Form | ASTM | AMS |
|---|---|---|
| Bar & Forging Stock | ASTM B637 | AMS 5701 |
| Forgings (Discs/Rings) | ASTM B637 | AMS 5701 |
| Plate & Sheet | ASTM B670 | -- |
| Wire | -- | AMS 5702 |
Chemical Composition (wt.%)
| Element | Min | Max | Role |
|---|---|---|---|
| Ni | 39.0 | 44.0 | Matrix; γ″/γ′ former |
| Cr | 14.5 | 17.5 | Corrosion/oxidation resistance |
| Fe | Balance | -- | Segregation dilution |
| Nb | 2.5 | 3.3 | γ″ former |
| Ti | 1.5 | 2.0 | γ′ former |
| Al | -- | 0.40 | γ′ former |
| C | -- | 0.06 | Carbide control |
| S | -- | 0.015 | Impurity |
Mechanical & Physical Properties
Room-Temperature (Solution 955C + Age 845C/3h + 720C/8h)
| Property | Value |
|---|---|
| Tensile Strength | >= 1000 MPa (145 ksi) |
| Yield Strength 0.2% | >= 700 MPa (102 ksi) |
| Elongation | >= 15% |
| Hardness | 32-38 HRC |
Elevated-Temperature (Typical)
| Temperature | Tensile (MPa) | Yield (MPa) |
|---|---|---|
| 20C | 1150 | 820 |
| 425C | 1000 | 720 |
| 540C | 950 | 690 |
| 650C | 800 | 620 |
Heat Treatment
Solution Anneal: 955-1005C (1750-1840F), oil quench or water quench.
Age (Triple): 845C/3h/AC + 720C/8h/AC (standard), or 760C/16h for improved toughness.
Industry Applications
| Industry | Component | Why 706? |
|---|---|---|
| Power Generation | Gas turbine rotor discs, generator retaining rings | Sound 1,200mm+ forgings impossible in 718 |
| Aero Engines | Compressor discs (large frames) | 718-class strength, better center quality |
| Oil & Gas | Large forged wellhead components | API 6A 718-compatible alternative |
| Petrochemical | Large flanges, tube sheets | Big-section soundness |
Quality Assurance: 7-Stage
- Raw Material: Ni, Fe, Nb, Ti verified by OES.
- VIM+ESR Melt: Nb +/-0.2%, Ti +/-0.1%, C <=0.04% internal. ESR for large ingots.
- Hot Working: 1050-1150C, finishing >=950C. Controlled reduction for center soundness.
- Solution Anneal: 955-1005C verified.
- Aging Verification: Hardness 32-38 HRC; tensile per lot.
- NDE: 100% UT immersion per AMS-STD-2154 Class A for discs.
- Documentation: EN 10204 3.1 MTC. SGS/TUV/BV witness.
Frequently Asked Questions
Q1: What is Inconel 706 used for?
Large gas turbine and generator rotor discs, aero-engine compressor discs, and any large forging where 718 segregation is unacceptable.
Q2: 706 vs 718?
718: higher strength (yield ~1034 MPa), limited to ~500mm sound sections. 706: 5-10% lower strength, sound to 1,200mm+. Choose 718 for small high-strength, 706 for large discs.
Q3: Why is 706 better for large forgings?
Niobium reduced from 5.2% to 2.9% suppresses Laves-phase channel segregation during solidification — the failure mode of large 718 ingots.
Q4: Is it weldable?
Limited — PH alloy. Forge/bolt rather than weld critical components.
Q5: What is the price?
$45-80/kg EXW. Contact sales@hangboalloy.com.
Q6: Product forms?
Bars (10-300mm), forged discs (to 1,200mm), rings, billets. SGS available.
Q7: What heat treatment?
Solution 955-1005°C + triple age (845/720°C).
Q8: Does it meet API 6A?
Yes — qualified as an API 6A718-compatible material for oilfield use.
Q9: What is the density?
8.08 g/cm3.
Q10: Does Shanghai Hangbo ship internationally?
Yes — FOB/CIF/DAP to 40+ countries.
Q11: What standards apply?
AMS 5701, ASTM B637.
Q12: What is the max service temperature?
~650°C continuous (γ″ overages above this).
Q13: Is it magnetic?
Non-magnetic (fully austenitic).
Q14: Why triple aging?
The 845°C stabilization controls γ″/δ morphology; the 720°C age develops fine strengthening precipitates — critical for large-section uniformity.
Q15: Can it replace 718 in discs?
For disc diameters above ~500mm, 706 is the standard choice; below that, 718.
Contact Shanghai Hangbo Alloy Group
| Channel | Details |
|---|---|
| Company | Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier |
| Website | www.nickel-alloy.com |
| Email (Sales) | sales@hangboalloy.com |
| Email (Technical) | hangbo@nickel-alloy.com |
| WhatsApp (Lisa) | +86 13611656360 |
| Address | Room 1508, No. 288 Shiyi Road, Baoshan District, Shanghai 200940, China |
Shanghai Hangbo Alloy Group - Complete Product Range
| Family | Available Grades |
|---|---|
| Pure Nickel | NI200, NI201, N4, N5, N6 |
| Monel | 400, 401, 404, K-500, R-405 |
| Inconel | 600, 601, 617, 625, 690, 693, 706, 718, X-750, 725 |
| Incoloy | 800, 800H, 800HT, 825, 925, 926, 945, A-286, 25-6HN, 27-7MO |
| Hastelloy | C-276, C-22, C-2000, C-4, G-30, G-35, G-50, X, B-2, B-3, B-4, HYBRID-BC1, N |
| Super Austenitic | 904L, Alloy 28, Alloy 31, 254SMO, 20Mo-6, AL-6XN |
| Chromium-Rich | Alloy 33 |
| High-Strength Stainless | Nitronic 50, Nitronic 60, PH13-8Mo |
| Chlorination-Resistant | Alloy 45 |
| Nimonic | 75, 80A, 90, 95, 105, 115, 263 |
| Haynes | 25, 188, 214, 230, 242, 282, 556, HR-120, HR-160 |
| RA Series | RA330, RA333 |
| Precision | 1J22, 1J46, 1J50, 1J79, 1J85, 3J21, 4J32, 4J36, 4J45 |
| High-Strength | 18Ni250, 18Ni300, AerMet 100 |
| Heating | Cr20Ni80, Cr40Ni60 |
| Specialty | Alloy 20, Alloy 59, Inconel 686, 602CA |
Product Forms: Bars(6-500mm) | Tubes(OD 6-610mm) | Plates(0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire(0.05-10mm) | Strip(0.02-4.0mm)
SGS/BV/TUV. Contact: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360 | www.nickel-alloy.com
