Designation by Standards

1.3346 S2-9-1 † HS2-9-1 M1 / /

Chemical Composition (in weight %)

C Si Mn Cr Mo Ni V W Others
0.82 max. 0.45 max. 0.40 3.80 8.60 - 1.10 1.70 -

M1 is a molybdenum, chromium, vanadium alloy tool steel generally known as a Molybdenum High Speed Tool Steel. It is on of the most widely available tool steels in use today. It is similar in properties to the tungsten tool steels (T series) at a lower. Very tough high-speed Mo steel good grindability.

Twist drills, thread cutting tools, hobs and dies for broaching and cold flow pressing, cross recess dies for screw manufacture, cold rolling for e.g. Sendzimir equipment.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 217
Density [g/cm3]: 8.0
Thermal conductivity [W/m.K]: 19.0
Electric resistivity [Ohm mm2/m]: 0.60
Specific heat capacity[J/g.K]: 0.46

Coefficient of Linear Thermal Expansion 10-6 oC-1

20-100oC 20-200oC 20-300oC 20-400oC 20-500oC 20-600oC 20-700oC
11.0 11.5 11.9 12.3 12.4 12.5 12.5

Soft Annealing
Heat to 820-850oC, cool slowly in furnace to 550oC then air. This will produce a maximum Brinell hardness of 262.

Stress Relieving
Stress relieving to remove machining stresses should be carried out by heating to 600-650oC, holding for one hour at heat, followed by air cooling. This operation is performed to reduce distortion during heat treatment.

0 Harden from a temperature of 1180-1219oC followed by air or oil quenching or warm bath at 550oC. Hardness after quenching is 64-66 HRC.

Tempering temperature: 530 - 560oC, at least 2x for at least 63 HRC.

Hot forming temperature: 1100-900oC.

Cold Working
This alloy may be cold worked in the annealed condition.

M1 is classified as a "medium" machinable alloy. Machining should be accomplished prior to hardening heat treatment followed by finish grinding. It has a rating of 50% that of the water hardening (W group) low alloy tool steels in regard to machinability.

Corrosion Resistance
This is not a corrosion resistant alloy. In use as tooling it is often coated with oil to prevent rusting. A light film of oil. or protective wrapping, is essential to keep it free from corrosion.

Consult the alloy supplier for information on weld procedures.

All technical information is for reference only.