How to choose cutting tools to cut hardened steel?

When selecting tools for cutting hardened steel, the following key factors need to be considered:

1. Tool material

Cubic boron nitride (CBN) cutting tools: With high hardness, high thermal stability, and good wear resistance, they are very suitable for cutting hardened steel with a hardness of HRC 55 and above.

Ceramic cutting tools: such as alumina ceramics and silicon nitride ceramics, which have high hardness and high temperature resistance, are suitable for high-speed cutting of quenched hard steel.

2. Geometric shape of cutting tools

Smaller front and back corners: to enhance the strength and wear resistance of the tool.

Negative chamfering: can increase the strength of the blade and reduce the risk of blade breakage.

Larger tool tip arc radius: helps improve tool durability.

3. Cutting parameters

Lower cutting speed: generally between 50-150 m/min, depending on the tool material and workpiece hardness.

Smaller feed rate and cutting depth: to reduce the generation of cutting force and heat.

4. Tool coating

Common coatings such as TiN and TiAlN can improve the wear resistance and adhesion resistance of cutting tools.

5. Cutting edge treatment of cutting tools

The edge that has been finely ground or polished can reduce friction during cutting and improve tool life.

For example, when machining hardened steel shafts with a hardness of HRC 60, CBN cutting tools can be selected. A geometric shape with a negative rake angle of -5 °, a rake angle of 8 °, and a tool tip radius of 0.8mm can be used. The cutting speed is 80 m/min, the feed rate is 0.1 mm/r, the cutting depth is 0.5 mm, and a TiAlN coating can be used to achieve good machining results.

In summary, the selection of cutting tools for cutting hardened steel requires comprehensive consideration of the above factors, and optimization and adjustment based on specific processing requirements and working conditions.