M2 High Speed Steel
M2 is a high speed steel comprised of a tungsten molybdenum mix. Typically used in applications requiring wear resistance, retaining hardness even when heated to the point of glowing red and great wear resistance. M2 is regarded as a successor to T1 in most applications due to it been generally superior mechanically speaking, its also has the benefit of been a lower cost. M2 has good machinability especially when compared to higher alloy cold work steels.
M2 has a large array of applications due to it having very well balanced properties. It sees use in areas such as milling equipment, taps and dies, metal saws and drill bits. Mostly where moderate hot work hardness is required, though it is also suitable for cold work applications such as forging, punching and pressing.
M2 Chemical Properties
To anneal M2 steel heat it to between 850-900 Celsius, ensure that the material is held at this temperature for at least 2 hours or one hour for every 25mm of thickness. Allow to cool in the furnace slowly. The peak hardness should be 248 Brinell.
Hardening M2 should be done in stages; first heat to between 450-500 Celsius then to between 850-900 Celsius, then heat to the final hardening temperature of 1200-1250 Celsius. Once the hardening temperature is achieved do not allow the steel to be left at the temperature for too long. Quench the steel in oil or brine once the temperature is down to 500 Celsius then air cool down to room temperature.
Heat the m2 to the required temperature, hold the M2 at this temperature for 2 hours or one hour per 25mm of thickness. Running this process twice is recommended.