GRADE GUIDE · INCONEL 718
Inconel 718 (UNS N07718) is the high-strength member of the nickel family: precipitation-hardenable to roughly 1,034 MPa yield while keeping nickel-alloy corrosion resistance. Aerospace built its reputation; in the Gulf it is the alloy of downhole tools, high-pressure fasteners and wellhead internals.
Also listed as: UNS N07718 · EN 2.4668 · NiCr19Fe19Nb5Mo3 · Alloy 718
Stock turns over piece by piece — what's listed is what exists. Post the spec you need and we match it against incoming material; you're alerted the moment something lands.
Where 625 gets strength from chemistry alone, 718 gets it from heat treatment: a niobium-driven ageing cycle precipitates hardening phases through the nickel-chromium-iron matrix, roughly tripling the annealed strength. That is jet-engine-disc territory — and exactly what oil-tool designers borrow for HPHT (high-pressure, high-temperature) downhole assemblies, where the alloy also carries NACE sour-service listings in controlled hardness conditions.
718 is bought overwhelmingly as bar for machined parts, and its machining is slow, hard work — which makes surplus bar ends genuinely valuable: a stub of certified aged bar can be a finished mandrel or fastener blank. Check each listing's certificate for condition (solution-annealed vs aged) — the two behave like different materials at the lathe and in service.
Strength versus breadth. 718 is age-hardened to about 1,034 MPa yield for machined high-load parts; 625 stays near 415 MPa but welds freely and covers a wider corrosion envelope. Structural tools take 718; overlay, piping and hot parts take 625.
Decisively. Solution-annealed bar machines easier and is aged after rough machining; already-aged bar is at full strength and hardness. The certificate states the condition — match it to your process plan.
Yes, more forgivingly than most age-hardenable alloys — its sluggish ageing response resists strain-age cracking. Welds in aged material still need re-ageing to restore full properties in the joint.