Hard shell - soft core: Horn has developed the new SG66 grade for turning workpieces having different hardness zones. When machining turned parts with hardened surface layers or with an interrupted cut, users quickly reach the limits of CBN inserts. This is where the new grade comes in. In combination with the fine-grain carbide, the aluminium-titanium-silicon chromium nitride layer delivers high performance when machining hardened steels up to 58 HRC. The maximum allowable temperature is 1,200 degrees Celsius (2,192 degrees Fahrenheit). Due to the high flexural strength of the carbide substrate, interrupted cutting is also possible in hardened materials. In addition to hard machining, the carbide grade is also suitable for reliably processing highly temperature resistant and other difficult-to-machine steel alloys.

The carbide grade SG66 is available for all common Horn insert systems. The in-house coating also enables a short delivery time for special tools. SG66 cannot replace the CBN grade. Horn has, however, filled the gap for particularly difficult groove turning applications. In comparison, the CBN grade achieves twice the cutting speed and more when machining through-hardened materials.