INCONEL 718Plus is a more advanced evolution of standard Alloy 718, built by rebalancing the classic 718 chemistry and adding cobalt and tungsten to the mix. That adjustment pushes the alloy's usable operating temperature roughly 50°F higher than standard 718 while holding on to much of the same forgeability, weldability, and shop-floor processability that made 718 the default choice for so many turbine components in the first place. The added cobalt slows the coarsening of strengthening precipitates at elevated temperature, and the tungsten reinforces solid-solution strength in the matrix, so the alloy keeps more of its room-temperature strength as parts run hotter.

Like standard 718, 718Plus is precipitation-hardened through a combination of gamma-prime and gamma-double-prime phases built around niobium, titanium, and aluminum. It's typically supplied solution-annealed and age-hardened, and shops most often encounter it in that condition rather than in a soft, fully annealed state. The result is a disk and rotating-component alloy that closes part of the performance gap between conventional 718 and higher-cost, harder-to-process superalloys, without requiring a completely different manufacturing approach.

718Plus shows up in gas turbine disks, spacers, seals, and other rotating hardware in both aerospace and industrial turbine applications where standard 718's roughly 1300°F temperature ceiling is limiting, but a jump to a cobalt- or higher-temperature nickel alloy isn't justified by the application.

718Plus machines like a tougher sibling of standard 718, which already has a reputation as one of the more demanding materials in a shop. The low thermal conductivity of the nickel matrix keeps heat concentrated right at the cutting edge instead of carrying it away in the chip, so tool tips run hot even at modest cutting speeds. The added cobalt and tungsten that give 718Plus its extra 50°F of temperature capability also mean the alloy holds its strength and hardness at those elevated cutting-zone temperatures better than standard 718 does — exactly the property that makes it harder on tooling.

Work hardening is a constant concern. Every pass leaves a hardened layer on the just-cut surface, so interrupted or light finishing cuts that ride over previously machined material accelerate notch wear at the depth-of-cut line. Chips also tend to weld and smear onto the rake face under heat and pressure, a galling tendency that dulls edges and can drag material off the workpiece surface if the coating or edge prep isn't matched to the alloy.

Rigid setups, sharp positive-rake geometries, and steady, uninterrupted feed rates all help keep the tool cutting cleanly rather than rubbing and work-hardening the surface. Because 718Plus retains more high-temperature strength than standard 718, expect somewhat lower cutting speeds and shorter tool life per edge than on 718, with coated carbide grades built for hot hardness and edge toughness generally outperforming uncoated tooling.