TOUGHTEC SF



 

  


General

Toughtec is a chromium - molybdenum - vanadium alloyed tool steel.

Characteristics found in TOUGHTEC

Very high wear resistance.

Good compressive strength.

Very good toughness.

Good dimensional stability at heat treatment and in    service.

Very good through - hardening properties.

Very good resistance to tempering back.

Good WEDM properties.

Good surface treatment properties.

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Typical Analysis %
C 1,6
Si 0,3
Mn 0,5
Cr 5.0
Mo
2,3
V
7,2
Standard Specification
None
Delivery
Condition
Soft annealed to approx
215HB
Colour Code
Green/ Brown

   

Applications

Toughtec is suitable for medium run to long run tooling of work materials where mixed (abrasive- adhesive) or abrasive wear and / or chipping / cracking and / or plastic deformation are dominating failure mechanisms.

Examples:

Screws and barrels for plastic processing.
Cold and hot forming rolls.
Hot shearing knives.
Hot forging trimming dies.
Wear parts.
Engineering applications.



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Properties

PHYSICAL DATA

Hardened and tempered to 53 HRC.

Temparature
20º C
(70º F)
200º C
(390º F)
400º C
(750º F)
Density, Kg/m³
Ibs/in³
7580
0,273
Modulus of elasticity
MPa
Psi

212 000
30.8 x 106

204 000
29,5 x 106

193 000
28,0 x 106
Specific heat
J/kg º C
Btu/Ib º F

460
0,11
-
-
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COMPRESSIVE STRENGTH
Hatdness HRC
CompressiveStrength Rc0,2(MPa)
50
1 650
52
1750
54
1850
56
1950
58
2050
60
2150

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IMPACT STRENGTH
Approximate room temperature impact strength at different tempering temperatures.

Specimen size : 7 x 10 x 55 mm(0,27 x 0,4 x 2.2") unnotched.

Hardened for 30 minutes , except at 1150º C(2100º F) where 10 minutes is used.Quenched in air. Tempered 2 x 2 hrs.


Relative chipping resistance for AISID2 ,PM 23, TOUGHTEC at 58HR and AISI H13 at 52 HRC. High value indicates good ductility.High temperature tempered condition.

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WEAR RESISTANCE
Relative abrsive wear resistance for AISI D2, Pm 23 , TOUGHTEC at 58 HRC and AISI H13 at 52 HRC.High value indicates good wear resistance.High temperature tempered condition.

Hot strength
Hot strength in longitudinal direction.The specimens have been heat treated to 52 HRC, 1050º C(1920º F)+580ºC(1080ºF),2 x2 hrs.

Effect of time at high temperature on hardness. The softening at high temperatures and different holding times are shown below.
The specimens have been heat treated to 52 HRC,
1050°C (1920°F) + 580°C (1080°F), 2 x 2h.

HEAT TREATMENT RECOMMENDATIONS
Soft Annealing
Protect the steel and heat through to 900°C(1650°F).Then cool in the furnace at 10°C(20°F)per hour to 650°C(1200°F), then freely in air.

Stress Relieving
After rough machining the tool should be heated through to 650°C(1200°F), holding time 2 hours.Cool slowly to 500°C(930°F),then freely in air.

Hardening
Preheating in two stages:600-650°C(1100-1200°F)and 900-950°C(1650-1740°F)
Austenitizing temperature : 1000-1150°C(1830 - 2100°F), normally 1050°C(1920°F).
Holding time: 30 min for <=1120°C(2050°F),
10minutes for> 1120°C(2050°F).
Protect the part against decarburization and oxidation during hardening.




Effect of testing temperature on impact energy.
Charpy-V specimens, longitudinal and short transverse direction.Approximate values for specimens fromØ25mm(4.9")bar.

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Heat treatment

SOFT ANNEALING

Protect the steel and heat through to 900ºC (1650ºF).  Then cool in the furnace at 10ºC (20ºF) per hour to 650ºC (1200ºF), then freely in air.

STRESS-RELIEVING

After rough machining the tool should be heated through to 650ºC (1200ºF), holding time 2 hours.  Cool slowly to 500ºC (930ºF), then freely in air.

HARDENING

Preheating temperature    : 600-650ºC (1100-1200ºF) and900-950ºC(1650-1740ºCF).
Austenitizing temperature : 1000-1150ºC (1830-2100ºF),normally 1050 ºC(1920ºF)
Holding time                    : 30 Min. for <=1120ºC(2050ºF),10min.for >1120ºC(2050ºF)


Protect the part against decarburization and oxidation during hardening.


Quenching Media

 High speed gas / circulating atmosphere.
 Vacuumfurnace (high speed gas with sufficient overpressure).
Martempering bath ,salt bath or fluidized bed at 500-550ºC(930-1020ºF)
 Martempering bath at 200 -350ºC (390-660ºF)

Note: Temper the tool as soon as its temperature reaches 50-70ºC(120-160ºF).
Harness and retained austenite as a function of austenitizing temperature.
10 minutes holding at 1150ºC(2100ºF), else 30 minutes.

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 Tempering

Choose the tempering temperature according to the hardness required by reference to the tempering graph below.Temper at least twice with intermittent cooling temperature.the lowest tempering temperature which should be used is 525ºC(980ºF).The minimum holding time at temperature is 2 hours.

Tempering Graph


 
 
 CCT-graph
 Austenitizing temperature 1050ºC(1920ºF).holding time 30 minutes.

cooling curveNo Hardness HV 10 T800-500
(Sec)
1
681
1
2
634
140
3
592
450
4
572
1030
5
536
3205
6
514
7370
 
 

TempºC Time hours HardnHv10
800
23,0
488
750
23,0
193
700
7,0
266
650
23,4
433
425
15,5
707
375
14,9
681
350
1,5
743
325
15,1
858
 
 

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SUB- ZERO TREATMENT
Pieces requiring maximum dimensional stability in service can be sub-zero treated as follows:
Immediately after quenching the piece should be sub-zero treated to -70ºC to-80ºC
(-95-110ºF),soaking time 1-3 hours, followed by tempering .
Sub- zero treatment will give a hardness increase of ~1 HRC .Avoid intricate shapes as there will be risk of cracking .
For the highest demands on dimensional stability , sub-zero cooling in liquid nitrogen is recommended after quenching and after each tempering
Dimensional Changes
The dimensional changes have been measured after austenitizing at 1050ºc(1920ºf)/30 minutes or 1120ºC(2050ºF)/30 min,cooling vacuum furnace at 1,1ºC/s(1,8ºF/s)between 800ºC(1470ºF) and 500ºC(930ºF)
Tempering: 2 x2 hrs at various temperatures.
Specimen size : 60 x 60 x 60 mm (2.4" x 2.4" x 2.4" )

 

 

 

 SURFACE TREATMENTS

 Some tool steels are given a surface treatment in order to reduce friction and increase wear resistance.The  most commonly used treatments are nitriding and surface coating with wear resistant layers produced via PVD  or CVD.

 The high hardness and toughness together with agood dimenional stability makes Caldie suitable as a substrate  for various surface coatings.


 NITRIDING

 Nitriding gives a hard surface layer that is resistant to wear and erosion.TOUGHTEC is normally high  temperature tempered at around 525ºC(980ºF).This means that the nitriding temperature used should not  exceed 500-525ºC(930-980ºF).Ion nitriding at a temperature below the tempering temperature used is  prefered.
 The surface hardness after nitriding is approximately 1150HV0.2kg.The thickness of the layer should be chosen  to suit the application in question.

Process
 Time
Depth
mm
inch
Gas nitriding at 510ºC(950ºF) 10hrs 0,15 0,0059
Plasma nitriding at 480ºC(895ºF) 10hrs
30hrs 		0,10
0,20 		0,0039
0,0079

 PVD
 Physical vapour deposition ,PVD, is a method of applying a wear - resistant coating at temperatures between  200-500ºc(390-930ºF) .

 CVD

 Chemical vapour deposition , CVD, is used for applying wear- resistant surface coatings at a temperature of  around 1000ºc(1830ºF).It is recommended that the tools should be seperately hardened and tempered in vacuum furnace  after surface treatment.
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 MACHINABILITY

 Relative machinability and grindabilty for TOUGHTEC, AISI D2,PM 23 and AISIH13.High value indicates good  machinability and grindability.

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 MACHINING RECOMMENDATIONS
 The cutting data below are to be considered as guiding values which must be adapted to existing local  conditions.
 Conditions: Soft annealed to approx .215HB.

 TURNING
Cutting Data Parameters Turning With Carbide
Rough Turning Fine Turning
Cutting speed ,Vc
m/min
f.p.m 		60-90
200-295 		90-110
295-360
Feed,f
mm/rev
i.p.r 		0,2-0,4
0,008-0,16 		0,1-0,2
0,004-0,008
Depth of cut ap
mm
inch 		2-4
0,08-0,16		 1-2
0,04-0,08
Carbide designation
ISO 		K15-K20* K15-K20*
* Use a wear resistant Al2o3-coated Carbide

 Drilling
 High speed steel twist drill

Drill diameter
Cutting Speed(Vc)
Feed (f)
mm
inch
m/min
f.p.m
mm/r
i.p.r
-5
-3/16
8-10*
26-33*
0.05-0.10
0.002-0.004
5-10
3/16-3/8
8-10*
26-33*
0.10-0.20
0.004-0.008
10-15
3/8-5/8
8-10*
26-33*
0.20-0.25
0.008-0.010
15-20
5/8-3/4
8-10*
26-33*
0.25-0.30
0.010-0.012

 For coated HSS drill Vc=16-20 m/min(52-66 f.p.m).

 Carbide drill
 
Type of drill
Cutting data parameters Indexable insert solid carbide Brazes Carbide¹
Cutting Speed (Vc)
m/min
f.p.m
80-100
260-330
40-60
130-200
40-60
130-200
Feed (f)
m/r
i.p.r

0.05-0.15²

0.002-0.006²
0.10-0.25²
0.004-0.010²
0.15-0.25²
0.006-0.01²

 ¹) Drill with internal cooling channels and brazed carbide tip
 ²) Depending on drill diameter.

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 Milling
 Face and square shoulder milling.

Cutting Data Parameters Milling With Carbide
Rough Milling Fine Milling
Cutting speed ,Vc
m/min
f.p.m 		50-70
164-230		 70-100
230-330
Feed,fz
mm/tooth
inch/tooth		 0,2-0,4
0,008-0,16 		0,1-0,2
0,004-0,008
Depth of cut ap
mm
inch 		2-4
0,08-0,16		 -2
-0,08
Carbide designation
ISO 		K20-P20* K15-P15*

 * Use a wear resistant Al2o3-coated Carbide

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 End milling

 
Type of milling
Cutting data Parameters Solid carbide Carbide indexable insert
High speed steel
Cutting Speed(Vc)
     m/mm
     f.p.m
30-40
100-130
70-100
230-330
12-16
39-52
Feed (fz)
     mm/tooth
     inch/tooth
0.03-0.2¹
0.001-0.008¹
0.08-0.2¹
0.003-0.008¹
0.05-0.35¹
0.002-0.014¹
Carbide designation
     ISo
     US
-
K15¹
-
 ¹)  Depending on radial depth of cut and cutter diameter.
 ² ) Use a wear resistant Al2o3-coated Carbide

 BAND SAWING
 A general grinding wheel recommendation is given below.
 For sawing of TOUGHTEC we recommond to use a carbide tipped band.The tooth pitch shall be coarse , but at  least three teeth must be engaged in the work piece at the same time.
 GRINDING
 Wheel recommendation

Type of grinding
Annealed condation
Hardened condition
Face grinding stright wheel
B151 R50B3¹
A46 Hv²
B151 R50B3¹
A46 Gv²
Face grinding segments
A36Gv
A46GV
Cylindrical grinding
B151 R50B3¹
A60KV²
B151 R50B3¹
A60JV²
Internal grinding
B151 R75B3¹
A60JV
B151 R75B3¹
A60IV
Profile grinding
B126 R100 B6¹
A 100JV²
B126 R100 B6¹
A 100IV²

 Electrical Discharge Machining,EDM

 If EDM is performed in the hardened and tempered condition,finish with "fine-sparking",i.e. low current , high  frequency.For optional performance EDM'd surface should be ground/ polished and the tool retempered a  approx.25ºC(50ºF) lower than the original tempering temperature.

 When EDM'ing larger sizes or complicated shapesTOUGHTEC should be tempered at high temperatures  >=525ºC(980ºF)

 Relative comparision of Uddeholm tool steel

 MATERIAL PROPERTIES AND RESISTANCE TO FAILURE MECHANISMS

   
Resistance to
Fatigue cracking resistance
 
uddeholm grade
Hardness/
Resistance to plastic
deformation
Machinability
Grindability
Dimension
Stability
Abrasive wear
Adhesive wear
Ductility/
resistance to
chipping
Toughness/
gross cracking
  TOUGHTEC
 
 
 
 
 
 
 
 
  AISI D2
 
 
 
 
 
 
 
 
  PM 23
 
 
 
 
 
 
 
 




 Further Information

 Please contact your local uddeholm office for further information on the selection, heat treatment, application  and availability of Uddeholm tool steels.
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