Understanding Carbide Insert Grades and Their Uses

What Are Carbide Insert Grades?

Carbide insert grades define the composition, hardness, toughness, and wear resistance of an insert. Each grade is engineered for specific applications, workpiece materials, and cutting conditions.

• Hard grades: High hardness for cutting hardened steels and alloys.

• Tough grades: High impact resistance, ideal for interrupted cuts and roughing operations.

• General-purpose grades: Balanced hardness and toughness for versatile applications.

Example: Sandvik Coromant’s GC series offers a variety of grades:

• GC1015: General-purpose for steel.

• GC1025: Tough grade for interrupted cutting.

ISO Carbide Insert Nomenclature

ISO 1832 provides a standardized code to describe every aspect of a carbide insert. Reading these codes is essential to match the insert to your machining needs.

Example ISO Code: CNMG 120408

Key Takeaways:

• Shape affects cutting forces and access to corners.

• Clearance angle determines how the insert contacts the workpiece.

• Tolerance ensures precision in finished parts.

• Chip breaker design improves chip evacuation and surface finish.

• Coating enhances wear resistance, heat resistance, and lubricity.

Types of Carbide Inserts by Application

Turning Inserts

• Use: External and internal turning on lathes or CNC turning centers.

• Materials: Steel, stainless steel, cast iron, non-ferrous metals.

• Example: CNMG or TNMG inserts with PVD or CVD coatings.

• Benefits: High precision, long tool life, consistent surface finish.

Milling Inserts

• Use: Face milling, shoulder milling, slotting on CNC milling machines.

• Materials: Aluminum, steel, titanium alloys.

• Example: Positive rake inserts like XOMX or OXMX series.

• Benefits: Efficient material removal, reduced vibration, improved chip evacuation.

Drilling & Special Inserts

• Use: Threading, grooving, parting, and specialty applications.

• Example: Kennametal or Taegutec threading inserts.

• Benefits: Precision for complex geometries, reduced tool changes.

Coating and Chip Breaker Considerations

Coatings:

• PVD (Physical Vapor Deposition): Thin, hard coating ideal for high-speed steel and stainless steel.

• CVD (Chemical Vapor Deposition): Thicker coating, excellent for abrasive materials like cast iron.

Chip Breakers:

• Designed to control chip formation and prevent workpiece damage.

• Example: Sandvik’s “M-class” chip breaker ensures smooth machining of medium steel.

Analogy: Think of chip breakers as “road signs” guiding metal chips safely away from the cutting zone.

Brand Comparison (Neutral)

All these brands follow ISO 1832, ensuring consistency in selection.

Practical Applications Across Industries

• Automotive: Engine blocks, shafts, and gear components using tough turning inserts.

• Aerospace: High-precision titanium and aluminum parts with coated milling inserts.

• Die & Mold: Complex cavity machining using ground inserts for fine tolerance.

• General Machining: Versatile grades for steel, stainless steel, and aluminum parts.

Conclusion

Selecting the right carbide insert grade is critical for productivity, cost efficiency, and quality. By understanding ISO insert nomenclature, coatings, chip breakers, and brand-specific features, you can make informed choices for turning, milling, and specialty applications.

Explore CNC Tools Depot’s extensive marketplace to find the perfect carbide inserts for your machining needs.