Udimet 500 (UNS N07500, W.Nr./DIN 2.4983, DIN designation NiCr18CoMoAlTi, SAE/AISI 684, AFNOR NCK19DAT) is a precipitation-hardenable nickel-chromium-cobalt superalloy developed by Special Metals as one of the original Udimet-family wrought and cast grades. It combines a substantial chromium addition for oxidation and hot-corrosion resistance with cobalt, molybdenum, aluminum, and titanium additions that drive gamma-prime (γ') precipitation hardening, giving the alloy high strength, good creep resistance, and good hot-corrosion resistance at elevated temperature.

Udimet 500 has a long production history in gas turbine hot-section components, including turbine blades and other rotating and static parts that must hold strength and dimensional stability at service temperatures up to roughly 760-870°C. It is typically supplied solution-treated and aged, and remains one of the more widely documented and commercially available grades in the Udimet family.

Machining Udimet 500 carries the same fundamental difficulties found across the nickel-based superalloy family. Nickel alloys conduct heat poorly compared to steels, so the heat generated at the cutting edge does not dissipate into the chip and workpiece as readily; instead it concentrates at the tool-chip interface, accelerating crater wear and edge deformation. Udimet 500 also work-hardens rapidly under the mechanical and thermal stress of cutting, so any hesitation, rubbing, or interrupted engagement at the cutting edge creates a hardened surface layer that is far tougher to cut than the base material - maintaining a constant, adequate chip load is essential.

Because it is precipitation-hardened by gamma-prime formed from its combined aluminum and titanium content, Udimet 500 retains much of its strength and hardness at elevated temperature, so tool edges stay under heavy mechanical load even as cutting temperatures climb, which drives notching and edge chipping if speeds are pushed too aggressively. The alloy is also prone to galling and built-up edge due to its chemical affinity for common tool materials, which can weld chip material to the cutting edge and tear the finished surface. Rigid setups, sharp and properly honed edges, coated carbide grades suited to superalloys, and consistent, generous coolant delivery are the standard countermeasures used to manage these combined effects.