Nimonic 86 takes the simple nickel-chromium base established by Nimonic 75 and adds a substantial molybdenum addition — roughly 10% — in place of the titanium hardening used in later Nimonic grades. Like 75, it stays solid-solution strengthened rather than age-hardenable: there's no precipitation heat treatment involved, so the molybdenum and chromium simply sit dissolved in the nickel matrix, thickening it up and improving high-temperature strength through solid-solution strengthening rather than through intermetallic precipitates.

The high chromium content (around 25%) gives 86 strong oxidation resistance in hot, aggressive environments, while the heavy molybdenum addition pushes its elevated-temperature strength meaningfully above what 75 can offer, closing some of the gap toward the age-hardenable grades without the complexity of a precipitation heat treatment. That combination makes 86 a useful middle-ground alloy — tougher and more heat-resistant than the simplest Nimonic grades, but without the machining and processing difficulty that comes with age-hardened microstructures. It's used in combustion equipment, exhaust hardware, and other moderately demanding high-temperature applications.

Nimonic 86 sits between the simple, comparatively easy-to-machine Nimonic 75 and the tougher, age-hardenable grades like 91 and 101. It's still solid-solution strengthened — there are no hard intermetallic precipitates to fight through — but the heavy molybdenum addition thickens the matrix and raises cutting forces and abrasive wear noticeably above what 75 requires. The alloy shares the usual nickel-superalloy traits: low thermal conductivity that concentrates heat at the cutting edge, a tendency to work-harden under light or rubbing cuts, and a chemical affinity for tool materials that promotes galling and built-up edge at low cutting speeds.

Because 86 lacks the aluminum-titanium precipitates of an age-hardened grade, it doesn't reach the same level of machining difficulty as Nimonic 91 or 101, but it's still meaningfully tougher on tooling than 75. Chip formation tends to stay manageable with the right chipbreaker geometry, and the alloy responds well to sharp, positive-rake tooling that shears rather than pushes through the material.

Rigid setups, steady feed rates, and a coated carbide grade with good hot hardness all help offset the added toughness from the molybdenum content. As with the rest of the Nimonic family, avoiding dwell time and light rubbing passes is the single most effective way to keep work-hardening from compounding tool wear.