The Inconel Machining Challenge
Inconel alloys are among the most difficult materials to machine in any industry. Their high nickel content maintains strength at cutting temperatures where most metals would soften, meaning cutting forces remain high regardless of speed. Thermal conductivity is approximately one-third that of steel, concentrating heat at the tool-chip interface to temperatures exceeding 1,200°C. Aggressive work hardening creates a hardened surface layer that progressively increases cutting forces. And the alloy's chemical affinity for cutting tool materials causes galling, built-up edge, and accelerated tool wear. These factors combine to make Inconel machining 5 to 10 times more expensive per cubic inch removed than conventional steel machining.
Our Machining Approach
CastAlloy has refined Inconel machining strategies through decades of production experience. Our approach uses ceramic and CBN inserts for roughing at surface speeds of 300–800 SFM, where these ultra-hard tool materials can withstand the extreme cutting temperatures. Coated carbide inserts with positive rake geometry handle finishing operations where surface integrity and dimensional precision are paramount. High-pressure through-spindle coolant at 1,000+ PSI ensures effective chip evacuation and tool cooling. And our CAM programming team optimizes tool paths for consistent chip load, avoiding the dwelling and light-cut conditions that trigger work hardening.
Capabilities and Tolerances
Our Inconel machining capabilities include multi-axis CNC milling, CNC turning, precision drilling and tapping, EDM (wire and sinker) for difficult features, and surface grinding. We achieve tolerances as tight as plus or minus 0.0005 inches on critical features and surface finishes down to 16 Ra microinches. We machine all major Inconel grades including 718, 625, 713C, 600, 601, and X-750 in both cast and wrought forms. Contact us for Inconel machining quotations.