CPM® REX® T15(HS)*
(AISI T15)
CPM REX T15 is a super high speed steel made by the Crucible Particle Metallurgy (CPM) process. It is a tungsten type high speed steel containing high vanadium for excellent abrasion resistance, and cobalt for good red hardness. CPM REX T15 is ideal for cutting difficult to machine materials where high frictional heating is encountered.
Typical Chemistry
Carbon 1.60%
Manganese 0.30% (0.70%)*
Silicon 0.30%
Chromium 4.00%
Vanadium 4.90%
Tungsten 12.00%
Cobalt 5.00%
Sulfur 0.06% (0.22%)*
Typical Applications
Broaches Milling Cutters
End Mills Spade Drills
Form Tools Shaper Cutters
Gear Hobs Taps
*The addition of .20/.25 S in larger diameter rounds (e.g. 2-9/16" and over) provides a uniform dispersion of small sulfides throughout the structure, resulting in machinability and grindability benefits with no deleterious effect on toughness.
Annealed Hardness: BH 245/275.

Machinability in the annealed condition is approximately 20% of W1 Tool Steel (1%C).

Thermal Treatments

Critical Temperature: 1550F(845C)

Forging: 2000-2100F(1095-1150C). Do not forge below 1700F(925C). Slow cool after forging.

Annealing: 1600F(870C), hold 2 hours, slow cool 30F(15C)/ hour maximum to 1000F(540C), then air or furnace cool. Hardness BHN 245/275.

Stress Relieving (After machining): (After machining) 1100-1300F(595-740C), hold 2 hours and air or furnace cool.

Straightening: Best done warm 400-800F(200-430C).

Hardening: (Salt, vacuum or atmosphere)

Preheat: 1500-1550F(820-845C), equalize. A second preheat at 1800-1900F(1010-1040C) is suggested for vacuum or atmosphere hardening.

High Heat: 2125-2250F(1165-1235C). Standard recommendation to achieve Rc 66-68 is to use 2225-2250F(1220-1235C).

Quench: Salt, oil or atmosphere quench to 1000-1100F(540-595C), equalize, then air cool to below 125F(50C) or hand warm. The vacuum or atmosphere quench rate through 1850-1300F(1010-705C) range is critical to achieve optimum heat treat response.

Temper: 1000F(540C) minimum recommended. Triple tempering required. (See table).

Stress-relieving (Hardened parts): (Hardened parts) Temper 30F(15C) below original tempering temperature or 1000F(540C) minimum.
Size Change During Hardening
Hardening
Temp.
Tempering
Temp.
HRC
Longitudinal
Size Change
%
°F
°C
°F
°C
2200
1205
1025
550
66
+.2
Surface Treatments
CPM REX T15 can be nitrided, steam tempered or titanium-nitride coated if desired. If the CVD TiN treatment is used, care is required in vacuum hardening.
Hardening Data
Tempering
HEAT TREAT RESPONSE ±1 HRC (NOTE A)
Temperature
2125F
2150F
2175F
2200F
2225F
2250F
°C
°F
(1165C)
(1180C)
(1190C)
(1205C)
(1220C)
(1235C)
As Quenced
67
66.5
66
65.5
64.5
64
540
1000
65
65.5
66
66.5
67
67.5
OPTIMUM FOR MAXIMUM TOUGHNESS AND EFFECTIVE STRESS-RELIEVING.
550
1025
64.5
65
65.5
66
66.5
67
565
1050
64
64.5
65
65.5
66
66.5
595
1100
62
62.5
63
63.5
64
64.5
620
1150
57
58.5
59.5
60.5
61
61.5
650
1200
54
55
56
57
57.5
58
NOTE A:
RESULTS MAY VARY WITH HARDENING METHOD AND SECTION SIZE. SALT OR OIL QUENCHING WILL GIVE MAXIMUM RESPONSE. VACUUM OR ATMOSPHERE COOLING MAY RESULT IN UP TO 1-2 HRC POINTS LOWER.
MINIMUM TIME AT
AUST TEMP (MINS)
10
10
10
5
5
5
MINIMUM NUMBER
OF TEMPERS (2 HRS)
3
3
3
3
3
3
Physical Properties
Modulus of Elasticity ...................................................................31 psi x 106 (214 GPa)
Specific gravity ............................................................................................................8.19
Density .......................................................................................0.296 lb/in3 (8193 kg/m3)
Coefficient of Thermal Expansion
Temperature
Range
Coefficient of Thermal
Expansion
°F
°C
in/in/°Fx10-6
mm/mm/°Cx10-6
70- 500
20-260
5.5
9.9
70- 800
20-425
6.1
11.0
70-1000
20-540
6.4
11.5
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