Inconel 622 is a nickel-chromium-molybdenum-tungsten alloy engineered for extreme resistance to corrosive attack. With a composition built around roughly 58% nickel, 22% chromium, 14% molybdenum, 3% tungsten, and a small iron addition, it belongs to the same chromium-molybdenum-tungsten family of alloys as the Hastelloy C grades, and it shares their characteristic ability to hold up under aggressive chemical exposure — chlorides, oxidizing acids, and mixed acid environments that would quickly degrade stainless steel. The high chromium content gives the alloy strong resistance to pitting and crevice corrosion, while the combined molybdenum and tungsten content reinforces its stability in reducing conditions, giving it a broader corrosion-resistance window than many single-purpose nickel alloys.

Beyond its chemical resistance, Inconel 622 retains useful strength and toughness across a wide temperature range and resists stress-corrosion cracking better than many austenitic stainless steels. These properties make it a common choice for chemical processing equipment, flue-gas desulfurization systems, pollution-control hardware, and other applications where both corrosion resistance and structural reliability are required. From a shop-floor perspective, it behaves like other nickel-based superalloys: it work-hardens readily and demands rigid setups, sharp tooling, and carefully controlled cutting parameters to machine efficiently.

Machining Inconel 622 presents the same core challenges found across the nickel-superalloy family. The alloy's low thermal conductivity means heat generated at the cutting edge cannot dissipate quickly into the chip or workpiece, so it concentrates right at the tool tip. That trapped heat accelerates flank and crater wear and makes coolant delivery and cutting-speed control critical to tool survival.

The material also work-hardens aggressively whenever a cutting edge rubs instead of shears cleanly. Light cuts, dull edges, or interrupted engagement all raise the hardness of the surface layer being cut, which then fights the next pass and can snowball into rapid edge breakdown. Because Inconel 622 retains its strength and hardness at the elevated temperatures generated during cutting, the tool never gets the "softening" relief that helps when machining plain carbon or low-alloy steels — the workpiece stays tough throughout the cut.

Finally, the alloy's nickel matrix has a strong affinity for the cobalt and iron found in many tool materials, which promotes adhesion, galling, and built-up edge on the cutting face. This tends to tear rather than shear the surface finish and can chip the coating right off an insert. Successful machining generally calls for sharp, positive-rake geometries, rigid tool holding, moderate cutting speeds paired with adequate feed to stay below the work-hardened layer, and coated carbide grades matched specifically to heat-resistant superalloys.