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Download T15 Spec sheet

WM T-15 powder metallurgy high-speed steel is cobalt-bearing super high-speed steel which can be heat treated to a hardness as high as 67 RC. A high volume of hard vanadium carbides provides very high wear resistance. The cobalt content provides excellent resistance to softening at high service temperatures (red or hot hardness). These properties translate into extended retention of hard, sharp cutting edges on tools produced from WM T-15. Because of the powder metal manufacturing, it is far easier to grind and exhibits impact toughness that is more than double that of tradition, ingot-cast T15 high-speed steel.


Carbon 1.60
Manganese 0.30
Silicon 0.30
Chromium 4.00
Tungsten 12.00
Molybdenum 0.75
Vanadium 4.90
Cobalt 5.00


High-performance broaches, form tools, milling cutters, end mills, taps, and reamers.


Density – 0.296 lb/in3

Specific gravity – 8.19

Coefficient of Thermal Expansion

70 – 200°F 5.90 x 10-6 in/in/°F
70 – 400°F 5.90
70 – 800°F 6.40
70 – 1200°F 6.74
70 – 1500°F 6.92

Critical Temperatures:
Ac1: 1520°F
Ac3: 1570°F
Ar1: 1445°F
Ar3: 1410°F


1500-1550°F, equalize.
A second preheat at 1850-1900°F is recommended for vacuum hardening


Heat rapidly from the preheat.

Furnace: 2150-2260°F

Salt Bath: 2150-2250°F

The use of lower austenitizing temperature will maximize impact toughness. The use of a higher austenitizing temperature will maximize hot hardness and wear resistance.


For pressurized gas, the furnace should have a minimum quench pressure of 4 bars. A quench rate of approximately 400°F per minute to below 1000°F is critical to obtain the desired properties.

For oil, quench until black, about 900°F, then cool in still air to 150-125°F.

For salt maintained at 1000-1100°F, equalize in the salt, then cool in still air to 150-125°F.


Temper immediately after quenching.

The typical tempering range is 1000-1100°F. Do not temper below 1000°F. Hold at temperature for 2 hours then air cool to ambient temperature. Triple tempering is required.



Annealing must be performed after hot working and before rehardening.

Heat at a rate not exceeding 400°F per hour to 1575-1600°F, and hold at temperature for 1 hour per inch of maximum thickness; 2 hours minimum. Then cool slowly with the furnace at a rate not exceeding 30°F per hour to 1000°F. Continue cooling to ambient temperature in the furnace or in air. The resultant hardness should be approximately 277 HBW.

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