Machining hardened steels, such as 20MNCR5, presents significant challenges due to their exceptional hardness (typically HRC 58-62 after carburizing) and high wear resistance. These properties, while ideal for demanding automotive components like gears and shafts operating under high speed and friction, demand high-performance cutting tools.
Polycrystalline Cubic Boron Nitride (PCBN) inserts are proven solutions for such difficult-to-machine materials, especially when dimensional accuracy and surface finish are critical. This article showcases two real-world applications using Moresuperhard PCBN inserts.
The Challenge: Machining Carburized 20MNCR5 Steel
Material: 20MNCR5 Carburized Steel
Hardness: HRC 58-62
Properties: Extremely high surface hardness and outstanding wear resistance. Ideal for high-stress components like automotive gears, shafts, and industrial transmission parts.
Machining Difficulty: Classified as a difficult-to-machine material due to its hardness. Achieving tight tolerances, good surface finish, or machining under interrupted cut conditions places high demands on tool performance and stability.
PCBN Tooling Solutions: Application Case Studies
1. Gear Facing with Light Interruption (CNGA 120408)
-Workpiece: Gear
-Material: 20MNCR5 Carburized Steel (Hardness: 58-60 HRC)
-Operation: Facing (Combining continuous cut and light interrupted cut)
-Insert: Moresuperhard 4-Edge CNGA 120408 PCBN Insert
-Parameters:
-Depth of Cut (Ap): 0.1 mm
-Feed Rate (f): 0.07 mm/rev
2. Shaft Finishing with Light Interruption (CNGA 120412)
-Workpiece: AUDI Car Shaft
-Material: 20MNCR5 Carburized Steel (Hardness: 62 HRC)
-Operation: Finishing (with light interrupted cut)
-Insert: Moresuperhard 4-Edge CNGA 120412 PCBN Insert
-Parameters:
-Depth of Cut (Ap): 0.4 mm
-Spindle Speed (S): 1400 rpm
-Feed Rate (f): 0.14 mm/rev
Choosing the Right PCBN Tool for 20MNCR5
The success in machining hardened 20MNCR5 steel hinges on selecting the appropriate PCBN grade and insert geometry tailored to the specific cutting conditions.
Moresuperhard offers specialized PCBN tool materials optimized for different scenarios encountered with gears, shafts, and similar components:
-Continuous Cutting: Grades designed for stable, uninterrupted machining.
-Light Interrupted Cutting: Grades offering enhanced toughness to handle minor interruptions (as demonstrated in the case studies above).
-Strong Interrupted Cutting: Robust grades specifically engineered for severe interruptions and impacts.
Selecting the correct grade is crucial for maximizing tool life, productivity, and achieving the required part quality (dimensional tolerance and surface finish) when working with this challenging material.
Conclusion
Hardened 20MNCR5 steel (HRC 58-62) is essential for high-performance automotive and industrial components but requires advanced tooling solutions.
As demonstrated in these gear and shaft machining applications, Moresuperhard's PCBN inserts (such as the CNGA 120408 and CNGA 120412) provide effective performance for finishing and light interrupted cutting operations on this difficult-to-machine material. The key to success lies in matching the PCBN grade to the specific cutting conditions encountered.
Contact us To Learn more about our range of high-performance Brazed PCBN Cutting Tools designed for challenging materials like hardened steel.
