SP9, SX6, HC1/HW2 Ceramic Inserts Cover Full Range of Cast Iron Machining

High-speed cast iron machining generates cutting temperatures that push conventional carbide beyond its effective operating range, particularly in dry and continuous-cut environments. The SP9, SX6, and HC1/HW2 are three ceramic insert grades covering roughing through finishing operations on gray and ductile cast iron, each built around a specific thermal and mechanical performance profile.

SP9 is a CVD-coated silicon nitride ceramic designed for roughing through finishing of both gray and ductile cast iron. The combination of a high-toughness silicon nitride substrate with a CVD coating provides fracture and wear resistance across a wide range of operations, including as-cast skin conditions. Minimal edge preparation reduces cutting forces. Recommended cutting conditions for gray cast iron rough turning run dry at 400 to 900 m/min (1,300 to 3,000 SFM), with a depth of cut of 0.5 to 3.5 mm (0.020 to 0.140 in) and feed of 0.3 to 0.6 mm/rev (0.012 to 0.024 IPR). For ductile cast iron rough turning with coolant, speeds run 300 to 600 m/min (1,000 to 2,000 SFM), depth of cut 0.5 to 3.0 mm (0.020 to 0.120 in), and feed 0.15 to 0.4 mm/rev (0.006 to 0.016 IPR). SP9 supports both turning and milling applications.

SX6 is an uncoated silicon nitride ceramic built for demanding gray cast iron roughing, including scaled surfaces. Its needle-like Si₃N₄ particle structure gives it greater resistance to chipping compared to alumina-based ceramics, along with high thermal shock resistance for wet applications. Recommended cutting conditions for rough turning run dry or wet at 500 to 1,200 m/min (1,600 to 4,000 SFM), depth of cut 0.5 to 3.5 mm (0.020 to 0.140 in), and feed 0.3 to 0.6 mm/rev (0.012 to 0.024 IPR). SX6 supports both turning and milling.

HC1/HW2 are alumina-based (white ceramic) grades designed for high-speed finish turning of gray cast iron in continuous-cut applications. HC1 prioritizes wear resistance; HW2 offers greater fracture resistance for situations where the finish operation involves more demanding conditions. Both grades run dry. Recommended cutting conditions cover speeds of 400 to 700 m/min (1,300 to 2,300 SFM), depth of cut 0.5 to 2.0 mm (0.020 to 0.080 in), and feed 0.1 to 0.4 mm/rev (0.004 to 0.016 IPR). Tooling application is finish turning only.

Features:

SP9 — CVD-Coated Silicon Nitride (Roughing to Finishing, Gray and Ductile Cast Iron)

• CVD-coated silicon nitride substrate
• Covers roughing through finishing in a single grade
• Gray cast iron rough turning (dry): 400–900 m/min (1,300–3,000 SFM); ap 0.5–3.5 mm (0.020–0.140 in); f 0.3–0.6 mm/rev (0.012–0.024 IPR)
• Ductile cast iron rough turning (wet): 300–600 m/min (1,000–2,000 SFM); ap 0.5–3.0 mm (0.020–0.120 in); f 0.15–0.4 mm/rev (0.006–0.016 IPR)
• Supports turning and milling
• Minimal edge preparation reduces cutting forces

SX6 — Silicon Nitride (Gray Cast Iron Roughing, Including Scaled Surfaces)

• Uncoated silicon nitride ceramic; needle-like Si₃N₄ particle structure
• First recommendation for roughing gray cast iron
• Rough turning (dry/wet): 500–1,200 m/min (1,600–4,000 SFM); ap 0.5–3.5 mm (0.020–0.140 in); f 0.3–0.6 mm/rev (0.012–0.024 IPR)
• High thermal shock resistance; suitable for wet cutting
• Supports turning and milling

HC1/HW2 — Alumina Ceramic (Gray Cast Iron Finish Turning)

• Alumina-based (white ceramic); thermally and chemically stable
• HC1: higher wear resistance; HW2: higher fracture resistance
• Finish turning (dry): 400–700 m/min (1,300–2,300 SFM); ap 0.5–2.0 mm (0.020–0.080 in); f 0.1–0.4 mm/rev (0.004–0.016 IPR)
• Finish turning only; continuous-cut applications

NTK Cutting Tools
ntkcuttingtools.com