M3 High Speed Steel

M3 high-speed steel contains carbon and vanadium levels that are intermediate between those of M2 and M4. This gives the steel a fine balance of wear-resistance and grindability, and provides superior resistance to abrasion and edge breakdown. This makes M3 high-speed steel a superb tool material for form tools and roll turning for severe cutting operations. An increase in tool life will also be experienced in the machining of heat-treated sections, castings and similar hard materials.

Other Known Names: REX M3-1®, PM M3, Corsair

Griggs Steel Color Code: Blue

Common Usage

Broaches, Blades, Form Tools, and Reamers

Physical Properties


0.295 lb/in3 (8166 kg/m3)

Specific Gravity


Modulus Of Elasticity

30 x 106 psi (207 GPa)


37-42% of a 1% carbon steel

High Speed Steel Properties Comparison

Griggs Steel chart

M3 High Speed Steel Chemical Composition


M3 High Speed Steel Heat Treating


M3 High Speed Steel Heat Treating

To minimize distortion and stresses in large or complex tools use a double preheat. Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1100°F (593°C) equalize, then heat to 1450-1550°F (788-843°C). For normal tools, use only the second temperature range as a single preheating treatment.

Heat rapidly from the preheat.

  • Furnace: 2200-2250°F (1204-1232°C)
  • Salt: 2175-2225°F (1191-1218°C)

Pressurized gas, warm oil, or salt. For pressurized gas, a rapid quench rate to below 1000°F (538°C) is critical to obtain the desired properties. For oil, quench until black, about 900°F (482°C), then cool in still air to 150-125°F (66-51°C). For salt maintained at 1000-1100°F (538-593°C), equalize, then cool in still air to 150-125°F (66-51°C).

Temper immediately after quenching. Typical tempering range is 1025-1050°F (552-566°C). Hold at temperature for 2 hours, then air cool to ambient temperature. Double tempering is required. Triple tempering is strongly recommended.

Annealing must be performed after hot working and before re-hardening

Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1550-1600°F (843-871°C), and hold at temperature for 1 hour per inch (25.4 mm) of thickness, 2 hours minimum. Then cool slowly with the furnace at a rate not exceeding 50°F per hour (28°C per hour) to 1000°F (538°C). Continue cooling to ambient temperature in the furnace or in air.