>M42 High-Speed Steel
M42 high-speed steel is a type of high-cobalt tough high-speed steel, with its American grade designated as M42 and the Chinese GB standard grade as W2Mo9Cr4VCo8.
Chemical Composition
C: 1.00~1.15%, Si: ≤0.65%, Mn: ≤0.40%, P: ≤0.030%, S: ≤0.030%, Cr: 3.50~4.50%, V: 0.95~1.35%, W: 1.15~1.85%, Mo: 9.0~10.0%, Co: 7.50~8.50%.
Performance Characteristics
High Hardness: After heat treatment, the hardness can reach 67~70 HRC. The hardness in the annealed state is ≤269 HBW, in the cold-drawn state is ≤285 HBW, and in the cold-drawn and annealed state is ≤277 HBW.
Excellent Red Hardness: It maintains high hardness at elevated temperatures, retaining above HRC 60 even at 600°C, ensuring good hardness and cutting performance in high-temperature environments.
Good Wear Resistance: Fine carbide particles with high hardness contribute to excellent wear resistance, making it suitable for manufacturing wear-resistant tools and molds.
Relatively High Toughness: Although its toughness is slightly lower than that of some high-speed steels, it still possesses a certain level of impact toughness compared to other high-hardness steels. The fine grain size, small carbides, and superior cleanliness of its powder metallurgy microstructure contribute to good impact toughness.
Heat Treatment Process
Isothermal Annealing: Temperature ranges from 800~880°C, followed by furnace cooling to approximately 600°C at a rate of 10~20°C/h, resulting in a hardness above HB269.
Preheating Temperature: 730~845°C.
Quenching Temperature: 1190~1210°C, with quenching methods including oil quenching, air cooling, or salt bath quenching.
Tempering Temperature: 540~595°C.
Main Applications
Cutting Tools: Suitable for manufacturing various high-wear and impact-resistant tools for heavy-duty cutting, such as scrapers, hobs, milling cutters, drills, and taps. It can cut difficult-to-machine materials like iron-based superalloys, cast superalloys, titanium alloys, and ultra-high-strength steels.
Mold Manufacturing: Used in high-grade stamping dies, screw dies, stamping heads requiring toughness and complex shapes, as well as cold forging dies and deep drawing dies.
Other Fields: Also applied in manufacturing precision mechanical parts such as high-temperature bearings and high-stress wear-resistant components, with applications in aerospace, medical devices, oil drilling, and other industries.