Why Integral Brazed CBN Inserts Fail: Understanding Vacuum Welding, Delamination and Chipping Risks

2026-10-05

Technical Articles

UHD explains how double-sided vacuum welding improves the structural stability of integral brazed CBN inserts and how welding quality, thermal cycling, thermal shock and cutting loads can contribute to voids, delamination and insert chipping in hard turning.

Integral brazed CBN inserts are designed for hard turning and high-load machining of hardened steel and cast iron.

UHD Integral Brazed CBN Inserts combine a CBN cutting head with a carbide substrate using a double-sided vacuum brazing structure. The design is intended to provide stable bonding, usable cutting edges and consistent performance in demanding turning applications.

Why Choose Integral Brazed CBN Inserts?

The brazed connection between the CBN cutting head and carbide substrate is important for tool stability. Proper bonding helps reduce risks such as voids, delamination and premature edge damage under suitable machining conditions.

Double-sided structure: provides more available cutting edges and can reduce tool-change frequency.
Vacuum brazing: supports a stable connection between the CBN head and carbide substrate.
High-load capability: the carbide substrate provides a tougher support base for demanding turning conditions.
Production consistency: stable insert structure helps manufacturers control tool consumption and process variation.

Integral Brazed CBN Inserts for Hard Turning

Select the CBN grade according to the workpiece material, cutting mode and required machining stage. UHD currently offers USN100, USN200 and USN650 grades for cast iron and hardened steel applications.

Grade	Key characteristics	Recommended application
USN100	Wear resistance and impact resistance	High-speed continuous or interrupted cutting of alloy, grey and ductile cast iron; roughing and semi-finishing
USN200	Wear resistance and heat resistance	High-speed continuous cutting of alloy, grey and ductile cast iron; semi-finishing and finishing
USN650	Wear resistance and impact resistance	High-speed continuous cutting of hardened steel, including bearing steel, die steel and tool steel; semi-finishing and finishing

Typical Applications

Integral brazed CBN inserts can be evaluated for CNC hard turning and high-load turning applications, including:

Automotive Components

Brake discs, flywheels and clutch pressure plates.

Compressors

Cylinders, upper bearings and crankshafts.

Bearings & Gears

Hardened components requiring stable turning performance.

Application Limitations

These inserts are not intended for every cutting condition. The following applications should be avoided or evaluated carefully:

Aluminium alloys and copper alloys
304 / 316 austenitic stainless steel
Low-carbon soft steel
High-precision small-hole finish boring
Ultra-finish machining

Strongly interrupted cutting, poor clamping or extreme cutting parameters should be reviewed before insert selection.

Available Specifications

Grade	ISO Specification	L / Size	φIC	S	R
USN100 USN200 USN650	TNGA160404/08/12	16.5	9.525	4.76	0.4
	TNGA220404/08/12	22	12.7	4.76	0.8
	WNGA080404/08/12	8.7	12.7	4.76	0.4
	WNGA080404/08/12	8.7	12.7	4.76	1.2
	CNGA120404/08/12	12.7	12.7	4.76	1.2
	DNGA110404/08/12	9.525	9.525	4.76	1.2
	DNGA150404/08/12	12.7	12.7	4.76	1.2
	VNGA160404/08/12	15.5	9.525	4.76	0.4

Additional specifications are available on request.

How to Select the Right CBN Insert

The right Integral Brazed CBN Insert depends on more than workpiece hardness. Before selection, consider:

Workpiece material and hardness
Continuous or interrupted cutting
Cutting speed, feed and depth of cut
Machine rigidity and workholding
Required surface finish and machining stage

UHD provides Integral Brazed CBN Inserts for hard turning and cast iron machining, with grade selection based on the specific workpiece and cutting conditions.

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