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 M4HC(HS) 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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