Tool Steel Selection for High-Speed Cutting Tools, Hobs & Broaches
Select high-speed steel by cutting speed, workpiece material, red hardness, abrasion resistance, tooth toughness, and edge chipping risk. For hobs, broaches, drills, milling cutters, and multi-edge cutting tools, the main choice is usually between toughness, hot hardness, wear resistance, and edge strength.
Quick Selection Guide by High-Speed Steel Grade
Choose the grade according to whether the tool is used for general cutting, hobs, broaches, difficult-to-machine alloys, or high-temperature cutting edges.
General HSS Standard
M2 High Speed Steel
Recommended for broaches, gear hobs, drills, milling cutters, and general high-speed cutting tools.
Reason: M2 gives an economical balance of toughness, strength, and cutting ability for standard carbon and alloy steels.
Cobalt HSS Upgrade
M35 High Speed Steel
1.3243 / SKH55
Recommended when cutting tools need better hot hardness than standard M2 under more demanding cutting conditions.
Reason: M35 is a cobalt-bearing high-speed steel direction, selected when cutting heat and edge softening become more serious than in normal M2 applications.
Difficult Materials
M42 High Speed Steel
1.3247 / SKH59
Recommended for heavy-duty cutting of difficult-to-machine materials and high-strength heat-treated steels.
Reason: M42 provides higher cobalt-bearing hot hardness, helping the cutting edge resist softening under severe machining heat.
Selection Summary
This table gives a faster comparison when the buyer already knows the cutting tool type and main failure risk.
| Cutting Tool Application | Main Requirement | Aobo Steel Grades |
|---|---|---|
| General broaches, gear hobs, drills, and milling cutters | Balanced toughness, strength, and cutting ability | M2 |
| Large or complex multi-edge cutting tools | Edge strength and fracture toughness against interrupted cuts | M2, M35 |
| Cutting where heat softening becomes a problem | Higher red hardness and hot hardness | M35, M42 |
| Difficult-to-machine alloys and high-strength steels | High hot hardness and resistance to edge softening | M42 |
| Applications where tooth chipping risk is high | Toughness and edge strength over maximum wear resistance | M2 |