Inconel 718 is also known as UNS NO7718,UNS N07718, W.N.2.4668, NiCr19Fe19Nb5,GH4169 (China)
Inconel 718 is a Ni-Cr-Fe base precipitation-hardening deformed superalloy with a long-term operating temperature range of -253℃~650℃ and a short-term operating temperature of 800℃. The alloy has high strength below 650℃ and has good fatigue resistance, radiation resistance, oxidation resistance and corrosion resistance, as well as good processability, weldability and long-term structural stability. Suitable for the manufacture of turbine discs, rings, blades, shafts, fasteners and elastic components, plate structural parts, casing and so on in aviation, aerospace, nuclear energy and petrochemical industries. The main products are hot rolled and forged bars, cold drawn bars, plates and strips, wire, pipes, rings and forgings etc. Alloy composition is divided into ordinary and high quality, high-quality Inconel 718 alloy carbon, niobium, sulfur and gas content control is more strict, mainly used for manufacturing all kinds of rotating parts.The processing technology can be divided into standard, high strength and direct aging. High strength and direct aging process are used for high quality Inconel 718 alloy forgings. The hot deformation temperature decreases successively, the average grain size of forgings refines successively and the strength increases successively, which can meet the application requirements of different rotating parts in aero engine.
Process Performance and Requirements
Vacuum Induction Furnace(VIM) and Electroslag Remelting Furnace(ESR)
- Product Chemical Composition
| Alloy | % | Ni | Cr | Fe | Mo | Nb | Co | C | Mn | Si | S | Cu | Al | Ti |
| Inconel 718 | Min | 50 | 17 | Rem | 2.8 | 4.75 | | | | | | | 0.20 | 0.65 |
| Max | 55 | 21 | | 3.3 | 5.50 | 1.0 | 0.08 | 0.35 | 0.35 | 0.015 | 0.30 | 0.80 | 1.15 |
- Product Physical Property
| Density | 8.24/cm3 |
| Melting Point | 1260-1320℃ |
| Magnetic Property | Nil |
| Fusing Temperature | 1260℃~1320℃ |
- Product Mechanical Property
| Variety and Specification | Heat Treatment | Tensile Property | Hardness | Durability |
| MPa | MPa | % | MPa | r/h | % |
| Plate/Sheet/Strip | --- | Anneal | ≤895 | ≤485 | ≥40 | HRB≤ 94 | --- | --- | --- |
| Plate/Sheet/Strip | ≤ 0.25 | Solid Solution | ≤965 | ≤550 | MV | HRB≤ 102 | --- | --- | --- |
| Plate/Sheet/Strip | ＞0.25~4.75 | ≤965 | ≤550 | ≥30 | HRB≤ 102 | --- | --- | --- |
| Plate/Sheet/Strip | ＞4.75~25 | ≤1035 | ≤725 | ≥30 | HRC≤ 25 | --- | --- | --- |
| Plate/Sheet/Strip | ≤ 0.25 | Standard Heat Treatment | ≥1240 | ≥1035 | MV | HRC≤ 36 | --- | --- | --- |
| Plate/Sheet/Strip | ＞0.25~25 | ≥1240 | ≥1035 | ≥12 | HRC≤ 36 | --- | --- | --- |
| Plate/Sheet/Strip | ≤ 0.38 | ≥965 | ≥795 | ≥5 | --- | 655 | ≥23 | --- |
| Plate/Sheet/Strip | ＞0.38~0.62 | ≥965 | ≥795 | ≥5 | --- | 655 | ≥23 | 4 |
| Plate/Sheet/Strip | ＞0.62~25 | ≥1000 | ≥825 | ≥5 | --- | 690 | ≥23 | 4 |
| Standard Number | Variety | Heat Treatment | ℃ | Tensile Property |
| MPa | MPa | % |
| Q/3B 4052 | Capillary Tube | Solid Solution | 20 | ≤ 1070 | ≤ 655 | ≥ 30 |
| Standard Heat Treatment | 20 | ≥ 1275 | ≥ 1035 | ≥ 12 |
| Remark: The whole tube tensile specimen is used |
| Standard Number | Variety | Heat Treatment | ℃ | Tensile Property | Hardness | Durability |
| MPa | MPa | % | % | MPa | r/h | % |
| GJB 2611A | Cold Drawn Rod | Standard | 20 | ≥ 1270 | ≥ 1030 | ≥ 12 | ≥ 15 | HBW≥ 345 | --- | --- | --- |
| 650 | ≥ 1000 | ≥ 860 | ≥ 12 | ≥ 18 | --- | 690 | ≥ 23 | ≥ 4 |
| GJB 3527 | Cold Drawn Wire for Springs | 20 | ≥ 1270 | ≥ 1035 | ≥ 12 | -- | HBC≥ 32 | --- | --- | --- |
Wire, 955℃±10℃x1h/AC+720℃士10℃x8h/FC(50℃士10℃/h)→620℃±5℃×(7`8)h/ AC,HRC≥32;
Rods and Forgings,(950~980)℃士10℃x1h/AC+720℃±5℃x8h/FC(50℃士10℃/h)→620℃±5℃ x8h/AC,HB≥346;
Plate and Welding Parts
Institution I:(940~960)℃/AC+(710~730)℃x(8~8.5)h/FC(50℃±10℃/h)→(615~620)℃x(8~8.5)h/AC, Solid Solution Holding time:(d)≤3mm,(25~30)min;(d)3mm~5mm,(30~35)min;
Tube,955℃士10℃x30min/AC(or air cooled)+720℃±10℃x8h/FC(50℃±10℃/h)→620℃±10℃,Make the total holding time not less than 18h, air cooled or forced air cooled
Direct aging treatment for disk forgings:720℃士10℃x8h/FC(50℃±10℃/h)→620℃±10℃x8h/AC
| Cold-drawn Wire | ¢0.3~¢18mm(Delivery in rolls or trays) |
| Hot-Rolling Wire | ¢5.5~¢20mm(Delivery in rolls) |
| Strip | thickness 0.1~4.5*width 6~350mm(Supply in rolls or straight strips) |
| Smooth Forged Rod on a Lathe | ¢60~350mm,L800-2500mm |
| Hot-rolled Burnishing | ¢20~80mm,L1000-5000mm |
| Cold Drawn and Burnishing | ¢2.5~18mm,L1000-8000mm |
| Seamless Tube | ¢1~275mm,wall thickness 0.2~30,L1000-8000mm |
