Selecting CBN Grades for Cast Iron, Hardened Steel and Production Turning
UHD integral brazed CBN inserts are designed for hard turning, cast iron machining and production applications where wear resistance, cutting-edge stability and predictable tool life are important. The correct insert should be selected according to workpiece material, hardness, cutting continuity, machining stage, cutting load, insert geometry and machine conditions.
CBN insert selection should begin with the machining application rather than the grade name alone. A suitable configuration needs to match the workpiece, cutting condition and required machining result.
UHD integral brazed CBN inserts combine a CBN cutting section with a cemented carbide substrate through a double-sided vacuum integral welding process. The structure is intended for production turning where the cutting edge must maintain consistent contact with the workpiece under heat and mechanical load.
The integral structure allows both usable sides to be considered during insert selection, helping increase available cutting edges and improve insert utilization.
The CBN section and carbide substrate are joined through vacuum welding to provide a stable connection for high-load turning applications.
The insert format is suitable for production environments where repeatability, edge utilization and controlled tool-change frequency are important.
UHD provides different integral brazed CBN grades for different combinations of material, cutting condition and machining stage. The following table can be used as an initial selection reference.
| Grade | Key Characteristics | Cutting Condition | Typical Workpiece | Machining Stage |
|---|---|---|---|---|
| USN100 | Balanced wear resistance and impact resistance | Continuous or interrupted cutting; suitable for relatively high cutting loads | Alloy cast iron, gray cast iron and ductile iron | Roughing and semi-finishing |
| USN200 | High wear resistance and thermal stability | Primarily continuous high-speed cutting | Alloy cast iron, gray cast iron and ductile iron | Semi-finishing and finishing |
| USN650 | Wear resistance combined with cutting-edge impact resistance | Stable continuous cutting of hardened materials | Hardened bearing steel, die steel and tool steel | Semi-finishing and finishing |
Grade selection should be confirmed against actual workpiece hardness, cutting speed, depth of cut, feed rate and cutting continuity. The table provides a starting point rather than a universal cutting recommendation.
Stable continuous cutting generally places greater emphasis on wear resistance and thermal stability. For cast iron, USN200 can be considered for semi-finishing and finishing, while USN650 is intended for suitable hardened-steel applications.
Interrupted or variable cutting conditions increase mechanical impact on the cutting edge. A grade with stronger impact resistance, together with an appropriate nose radius and stable workholding, should be considered.
Roughing normally involves a higher material-removal rate, larger cutting loads and greater risk of edge impact. Grade selection should prioritize edge stability together with suitable insert geometry and machine rigidity.
Finishing requires control of dimensional accuracy, surface quality and edge wear. Stable machines, appropriate nose radius and controlled cutting parameters become increasingly important.
Integral brazed CBN inserts are mainly used for turning cast iron and hardened steel components. Typical applications include automotive parts, compressor components, bearings, gears and other high-volume industrial components.
Brake discs, flywheels, clutch pressure plates and other cast iron or hardened components.
Cylinder components, upper bearings, crankshafts and related cast iron parts.
Hardened bearing components, gears and other precision parts requiring controlled turning processes.
Cast iron and hardened steel components where high material-removal efficiency and repeatable machining are required.
Integral brazed CBN inserts can be used on conventional CNC lathes and hard-turning machines when the insert, toolholder and machining conditions are properly matched. Machine rigidity and workholding stability are particularly important when machining hardened materials or components with interrupted cutting.
These applications may require a different CBN grade, edge preparation, insert geometry or machining strategy. Application information should be reviewed before final selection.
Henan UHD Ultrahard Tools Co., Ltd. develops and manufactures CBN and diamond cutting tools for industrial machining applications. UHD combines superhard material development, CNC grinding, digital production systems and precision inspection to support standard and application-specific tooling requirements.
For international B2B customers, UHD can evaluate standard integral brazed CBN inserts as well as non-standard tooling requirements according to the actual machining process. The selection can be based on workpiece material, hardness, component geometry, cutting continuity, machining stage, current insert specification and machine conditions.
If you are unsure which CBN grade or insert configuration is suitable, send UHD your workpiece material and hardness, machining operation, current insert model, cutting conditions and machine information. UHD can evaluate the application and recommend a suitable integral brazed CBN insert configuration.
Get a CBN Insert Recommendation
Tell us your workpiece, quantity, and tooling requirement. Our team will reply with a practical solution.
