Project Description

Overview

N07718 (Inconel 718) is a superalloy strengthened by niobium-driven γ″ (Ni₃Nb) precipitation. It operates from cryogenic (−253 °C) to 700 °C with outstanding tensile, fatigue, and creep-rupture performance, plus oxidation resistance to 982 °C. Its exceptional weldability without strain-age cracking makes it the dominant nickel alloy in aerospace turbomachinery, oil & gas downhole equipment, and power generation — representing roughly 70 % of all Ni superalloy production by volume.

N07718 Inconel 718 round bar product
N07718 / Inconel 718 round bar

Equivalent Grades & Standards

Standard Body Designation / Specification Scope
UNS N07718 Unified Numbering System designation
ASTM B637 · B670 · A1014 Bar/forgings · plate/sheet/strip · high-temp bolting
AMS 5596 · 5597 · 5589 · 5590 · 5662 · 5663 · 5664 · 5832 Sheet/strip · tube · bar/forgings/rings · welding wire
EN / DIN W.-Nr. 2.4668 · NiCr19Fe19Nb5Mo3 · EN 10269 Fastener stock; pressure-service bar
AFNOR NC 19 Fe Nb French national designation
API API 6A 718 / NACE MR0175 Oil & gas wellhead; sour-service components

Applications by Industry

Aerospace
Turbine discs, compressor blades, turbine blades, engine casings, thrust reversers, nacelle structural tubing, wheels, spacers, high-temperature stud bolts, fasteners
Oil & Gas
HPHT downhole completion tools, subsurface safety valve bodies, casing connectors, wellhead flanges, sour-service fasteners
Power & Nuclear
Gas turbine shafts, turbocharger rotors, heat exchanger tubing, nuclear reactor vessel fasteners, pressure vessel rings

Supply Forms & Sizes

Form Typical Size Range Key Specification
Round Bar / Rod Ø 5 – 800 mm AMS 5662 / 5663 / 5664 · ASTM B637
Flat Bar Thickness 6 – 150 mm ASTM B637
Plate / Sheet / Strip 0.1 – 100 mm thick AMS 5596 / 5597 · ASTM B670
Seamless Tube OD 6 – 300 mm AMS 5589 / 5590
Wire Ø 0.1 – 10 mm AMS 5832 (welding wire)
Forging / Billet Custom / per order ASTM B637 · AMS 5662

Chemical Composition — ASTM B637 / AMS 5596 (wt %)

Ni Cr Fe Nb + Ta Mo Ti Al Co max C max B max
50–55 17–21 Bal. 4.75–5.50 2.80–3.30 0.65–1.15 0.20–0.80 1.00 0.08 0.006

Also: Mn ≤ 0.35 · Si ≤ 0.35 · Cu ≤ 0.30 · P ≤ 0.015 · S ≤ 0.015 (all max, wt %)

Mechanical Properties — Room Temperature, Bar

Condition / Spec UTS (MPa) YS (MPa) El. (%) Hardness
Solution Annealed — AMS 5662 825–1000 585–760 ≥ 30 ~ 25 HRC
Sol. + Double Aged — AMS 5663 ≥ 1275 ≥ 1034 ≥ 12 ≥ 331 HBW

AMS 5663 double-aging cycle: 954 °C × 1 h, air cool → 718 °C × 8 h → furnace cool 56 °C/h to 621 °C × 8 h, air cool. Alloy retains > 80 % of room-temperature strength at 650 °C.