Introduction

In the field of modern mechanical machining, efficient machining of hardened steel (hardness above HRC45) has always been a major

 challenge facing the manufacturing industry. The emergence of cubic boron nitride (PCBN) tools has completely changed this situation,

 making it possible to "turn instead of grind" hardened steel. This article will deeply analyze the technical principles, performance advantages

 and typical applications of PCBN tools to help manufacturing companies achieve an efficiency revolution in hardened steel machining.

Technical characteristics of PCBN tools

Cubic boron nitride (PCBN) is the second artificial superhard material after artificial diamond, with the following unique properties:

Ultra-high hardness: microhardness 3000-5000HV, second only to diamond

Excellent thermal stability: can withstand high temperatures of 1200-1500℃ without phase change

Good chemical inertness: no chemical reaction with iron-based materials at high temperatures

Moderate toughness: better impact resistance than PCD tools

PCBN tools are usually sintered by CBN micropowder (content 40-90%) and ceramic binder under high temperature and high pressure. 

According to the different CBN content and binder, they are divided into multiple grades, suitable for different processing scenarios.

Outstanding advantages of PCBN tools in hardened steel processing

1. Realize the process revolution of "turning instead of grinding"

Traditional hardened steel processing requires turning first and then grinding, while PCBN tools can be directly turned to achieve 

grinding-level accuracy (Ra0.4μm or less). A bearing company processes HRC60 bearing rings. After using PCBN tools, the grinding 

process is eliminated, and the efficiency is increased by 3 times.

2. Tool life is significantly extended

When processing hardened steel, the life of PCBN tools is 20-50 times that of cemented carbide. A gear factory processes HRC58-62 

gear end faces. Carbide tools need to be replaced every 10 pieces, while PCBN tools can process more than 300 pieces.

3. Processing efficiency is greatly improved

The cutting speed allowed by PCBN tools can reach 2-4 times that of cemented carbide. When processing hardened steel, the cutting 

speed can usually reach 100-300m/min, and the feed rate is 0.1-0.3mm/r.

4. Reduce comprehensive production costs

Although the unit price of PCBN tools is relatively high, the unit cost can be reduced by 30-60% due to reducing the grinding process, 

improving efficiency and extending tool life. A hydraulic parts manufacturer saves more than 1.5 million yuan in costs annually.

Typical application scenarios of PCBN tools

Bearing industry: finishing of bearing rings and raceways

Gear processing: finishing of hardened gear end faces and outer circles

Mold manufacturing: semi-finishing and finishing of hardened mold surfaces

Auto parts: hardened hardware processing such as drive shafts, camshafts, brake discs

Roller repair: turning and repair of hardened layer on the surface of rollers

PCBN tool selection guide

The following key factors need to be considered when selecting PCBN tools:

CBN content selection:

High content (80-90%): continuous cutting of high hardness materials

Medium content (50-70%): general hardened steel processing

Low content (40-50%) : Intermittent cutting or roughing

Binder type:

Metal binder: good toughness, suitable for intermittent cutting

Ceramic binder: good wear resistance, suitable for continuous finishing

Tool geometry:

Rake angle: usually 0° to -7°

Tool tip arc: small for finishing (0.2-0.4mm), large for roughing (0.8-1.2mm)

Cutting parameter optimization:

Cutting speed: 100-300m/min

Feed rate: 0.05-0.3mm/r

Deep cutting: 0.1-0.3mm for finishing, 0.5-1.5mm for semi-finishing

PCBN tool usage tips

Machine tool requirements: high rigidity High-speed machine tools are preferred to avoid vibration

Cooling method: dry cutting or minimal lubrication (MQL) to avoid severe thermal shock

Tool tip treatment: Appropriate chamfering can increase tool life

Wear monitoring: Regularly check the wear of the back tool face and transfer it in time

Industry application cases

Case 1: A well-known bearing company uses PCBN tools to process HRC60-62 bearing rings, achieving complete "turning instead 

of grinding":

Surface roughness Ra0.4μm

Roundness 0.005mm

Production efficiency increased by 300%

Annual cost savings of 2.8 million yuan

Case 2: Automobile gearbox gear processing:

Material: 20CrMnTi quenching Hard HRC58-62

Process: PCBN tool completes end face and outer circle processing in one clamping

Replaces the original grinding process

Single-piece processing time is shortened from 25 minutes to 8 minutes

Future development trend

Material innovation: New materials such as nanostructured PCBN and gradient functional PCBN

Compound processing: Combination of PCBN tools with new processes such as ultrasonic vibration

Intelligent application: Tool status monitoring and adaptive processing system integration

Application expansion: Extend to new fields such as aerospace and energy equipment

Conclusion

PCBN tools provide a disruptive solution for hardened steel processing and are promoting the widespread application of the "turning 

instead of grinding" process. With the continuous advancement of material technology and tool design, the performance boundaries 

of PCBN tools will continue to expand. The correct selection and use of PCBN tools will help manufacturing companies gain a decisive 

competitive advantage in the field of hardened steel processing.

For PCBN tool selection support or free processing trials, please visit our official website or contact the local technical service team.

Keywords: PCBN tools, cubic boron nitride tools, hardened steel processing, turning instead of grinding, hard turning, tool life, efficient 

processing, bearing processing, gear processing, superhard tools