M42 high speed steel | 1.3247 | HS2-9-1-8 | GB W2Mo9Cr4VCo8 | SKH59

M42 high speed steel | 1.3247 | HS2-9-1-8 | GB W2Mo9Cr4VCo8 | SKH59

M42 high speed steel is a cobalt molybdenum tools steel, the addition of 8% cobalt means that M42 delivers superior red-hardness when compared to M2. The composition of M42 makes for a good balance of toughness and hardness and can be found widely used for all types of cutting tools, often used for machining materials and super alloys that are difficult to machine. M42 high speed steel has a heat-treated hardness in the range 68 to 70 HRC.

Chemical Composition

Annealing 

It is recommended that M42 is annealed after hot working and before re hardening. Heat to 850°C – 900°C at a rate of no more than 220°C per hour. Hold at temperature for a minimum of two hours or one hour per 25mm of thickness. Cool slowly to 700°C.

Stress relieving 

Heat to 600°C - 700°, soak for approx. 2 hours at temperature, slow cool to 500°C.

Hardening

Hardening M42 high speed steel is carried out in two steps. Pre heat the steel thoroughly to 450°C – 500°C, then increase heat to 1050°C – 1190°C, hold for a short time then quenching to about 550°C. Finally cool in air to hand warm.

Tempering

Temper M42 at between 510-595°C three times for at least 1 hour at full temperature is recommended. Cool in still air to room temperature between tempering treatments.

Forging 

Pre-heat slowly to 650 - 760°C and soak. Increase more quickly to the forging temperature of 1010 - 1150°C and equalise prior to forging. If the temperature drops below 980°C re-heating will be required. Cool the M42 very slowly after forging.

Applications

M42 is a high-speed steel for conditions that demand excellent hot hardness. M42 is suitable for cutting tools such as, twist drills, broaches, taps, milling cutters, saws, reamers, bandsaw blades and cold work tools.