Udimet 630 is a precipitation-hardenable nickel-chromium-cobalt superalloy in the Special Metals Udimet family, associated with the DIN-style designation NiCr19NbMo. Like other Udimet grades, it is strengthened by gamma-prime (γ') precipitation from combined aluminum and titanium additions, with niobium (columbium) and molybdenum contributing further precipitation and solid-solution strengthening. Compared with the older, more widely documented Udimet 500 and Udimet 700 grades, Udimet 630 carries a notably higher aluminum fraction relative to titanium, consistent with the later, higher-strength direction the Udimet family took as alloy design matured.

As with other members of this alloy family, Udimet 630 is intended for elevated-temperature service in gas turbine and similar high-temperature rotating or static hardware, where a combination of high strength, creep resistance, and oxidation resistance is required. This is a less commonly documented trade name compared with Udimet 500/700/710; specific mill certificates should always be consulted to confirm exact composition and heat-treatment condition for a given lot.

Udimet 630 carries the same core difficulties found across the nickel-based superalloy family. Thermal conductivity is low, so heat generated at the cutting edge concentrates at the tool-chip interface rather than dissipating into the chip, accelerating crater wear. The alloy work-hardens rapidly under cutting forces, so a consistent, adequate chip load must be maintained throughout the cut - any hesitation or rubbing produces a hardened surface skin that is markedly tougher to remove on the next pass.

Udimet 630's relatively high combined aluminum and titanium content drives a substantial gamma-prime volume fraction, which means the alloy retains considerable strength and hardness at the elevated temperatures generated during cutting - tool edges stay under heavy mechanical load even as heat builds, and the alloy's affinity for common tool materials makes it prone to galling and built-up edge. Rigid setups, sharp positive-rake carbide grades engineered for superalloys, moderate-to-low cutting speeds, and generous, consistent coolant delivery are the standard countermeasures for this alloy family.