Inconel is Special Metals' trademarked family of nickel-chromium-based superalloys, known for holding onto strength and resisting corrosion and oxidation at temperatures that would defeat most other metals — a combination that has made the family standard in jet engines, gas turbines, and chemical processing plants. Inconel 600 is the original, classic grade in the family, a solid-solution-strengthened nickel-chromium-iron alloy valued for its high-temperature oxidation resistance and broad corrosion resistance across a wide range of chemical environments.

600SP denotes standard Inconel 600 base chemistry supplied to a special (SP) practice — typically tighter grain-size control, additional mechanical-property testing, or supplementary certification requirements beyond the standard mill specification. It is not a separate alloy composition; mills and distributors use the "SP" designation to flag material produced or tested to enhanced requirements for critical applications such as high-integrity tubing, aerospace hardware, or components where consistent grain structure matters for forming or fatigue performance.

Because the underlying chemistry is unchanged from standard 600, the machining behavior, cutting-tool selection, and general handling of 600SP track the classic grade closely. The practical difference shows up mainly in certification paperwork and dimensional/microstructural consistency rather than in how the material responds at the cutting edge.

Because 600SP is chemically standard Inconel 600, its machining challenges are the same ones every solid-solution nickel-chromium-iron alloy presents. Thermal conductivity is roughly a third that of carbon steel, so cutting heat concentrates at the tool tip instead of clearing out in the chip, which drives up edge temperature and accelerates diffusion and notch wear on the insert.

The alloy work-hardens under cutting pressure, so a dull edge, light cut, or excessive dwell leaves a hardened layer that the next pass has to cut through, and it retains a large share of its room-temperature strength even as the cutting zone heats up — unlike steel, which softens noticeably under the same heat. That retained hot hardness, combined with the alloy's tendency to gall and adhere to the cutting edge, is what pushes cutting forces and tool wear above what a comparable steel part would see.

Sharp, positive cutting geometries, rigid low-vibration work-holding, and steady feed rates that keep the tool engaged rather than rubbing all help manage wear and surface finish. Since 600SP is frequently supplied as tubing or bar for critical, tightly toleranced components, machinists should also pay close attention to consistent chip control and finish quality, since the certification requirements that come with the SP designation often carry through to the finished part's surface and dimensional requirements.