HSS M42 material,high-speed steels  (HSS for short).

What is M42 Steel?

M42 steel is a super cobalt high speed steel known for its exceptional hardness, wear resistance, and heat resistance properties. It belongs to the M-series of high-speed steels  (HSS for short), which are specifically designed for applications requiring high cutting speeds and excellent tool life. HSS M42 material is widely used in the manufacturing industry, particularly in CNC machining processes that demand superior performance.
It’s important to note that there might be slight variations in the naming conventions used in different countries.

Some names of M42 tool steels commonly used worldwide:

Common designations of M42 steel
American Iron and Steel Institute (AISI) Chinese national standard (GB/T 9943) German Institute for Standardization (DIN) Japanese Industrial Standards (JIS)
M42 W2Mo9Cr4VCo8 S2-10-1-8 (1.3247) S2-10-1-8 (1.3247)

What is M42 steel composition?

The chemical composition of M42 high-speed steel typically includes the following elements:

Element Carbon Manganese Silicon Chromium Molybdenum Vanadium Tungsten


Symbol C Mn Si Cr Mo V W Co
Composition 1.05-1.15% 0.15-0.40% 0.15-0.65% 3.50-4.25% 9.00-10.00% 0.95-1.35% 1.15-1.85% 7.75-8.75%

How to heat treating M42 Steel?

Heat treating is a critical process for optimizing the M42 tool steel material properties. The typical heat treating steps for M42 cobalt steel include:


The steel is preheated to a specific temperature range to ensure uniform heating throughout the material.


The preheated steel is heated to a high temperature, usually between 1160-1200°C(2120-2190°F), so that its microstructure is transformed into austenite, a high-temperature phase.


The austenitized steel is rapidly cooled by quenching in a suitable medium, such as oil or air, to achieve high hardness and martensitic structure.


Quenched steel will be tempered at a lower temperature, generally 540-565 ° C (1000-1050°F) or so, to eliminate internal stress, improve toughness and strength, hardness can reach 66HRC~69HRC.

What Kind of Thermal Treatment can M42 Steel Do?

In addition to heat treating, material M42 can undergo various  thermal treatments to further enhance its properties for specific applications. These treatments include:

1.Cryogenic Treatment:

The steel subjected to extremely low temperatures, typically below -100°C (-148°F), to further refine its microstructure and improve wear resistance.

2. Nitriding:

The steel is exposed to nitrogen gas or a nitrogen-rich environment at elevated temperatures, resulting in the formation of a hard nitride layer on the surface. This layer enhances wear resistance and reduces friction.

What are the Applications of M42 Steel?

1.Cutting Tools:

It is widely used for manufacturing high-performance cutting tools, such as drills, end mills, reamers, and taps. Its high hardness, wear resistance, and heat resistance make it suitable for machining tough materials like stainless steel, cast iron, and heat-resistant alloys.

2. Milling Cutters:

The steel is employed in the production of milling cutters used for precision milling operations. It enables high-speed cutting, excellent chip evacuation, and prolonged tool life.

3. Punches ND Dies:

It is utilized for creating punches and dies used in metal stamping operations. Its hardness and toughness allow for efficient and precise shaping of various materials.

4.Aerospace Components:

The steel is favored in the aerospace industry for manufacturing critical components, such as turbine blades,engine parts, and aircraft structural components. Its high strength and heat resistance enable reliable performance in demanding environments.


M42 steel is a high-speed steel alloy that offers exceptional hardness, wear resistance, and heat resistance properties, making it an ideal choice for CNC machining applications. Its chemical composition, heat treating processes, and thermal treatments contribute to its superior performance. From cutting tools to aerospace components, M42 tool steel used in the precision machining operations.
U-Need specializes in CNC machining services using premium materials like M42 steel. Contact us (E-mail: info@uneedpm.com) to discuss your project requirements and benefit from our expertise in precision machining.