FM ALLOY

DURO-SPDURO-V5
DURO-V2
Steels for precision dieBlanking punch

The DURO Series is high performance steel for die that exceeds P/Mhigh-speed steel with a balance of wear resistance and toughness

2High wear resistance than P/M high-speed
steel in high friction speed range(adhesive wear range)
SP, V53Superior toughness than P/Mhigh-speed steel
V2

V2
V5Matrix
High-speed steel

P/M HSSToughness

1Toughness decrease is small even if
surface roughness worsens
SP, V5, V2

BetterFeatures

SPM2
D2

Wear resistance

BetterChange in bending strength
Shimadzu Autograph
Sample: 5×10×60 mm

Charpy impact testing machine
Sample: 5×10×60 mm Notch: None

Span: 50 mm

120

DURO-V2

DURO-V2
Charpy impact value (J/cm2)

Bending strength (GPa)6

Change in impact value

DURO-V54P/M HSS

DURO-SP280

DURO-V540

Feature 3

DURO-V2 has superior toughness
0Ground surface

Surface roughness
worsening(Electro discharge machining)

V Toughness decreases due to worseningof surface roughness
Steel grade
DURO-SPDURO-V5
DURO-V2
P/M HSSAdvancement of wear
Remaining tool marks

Worseningsurface
roughness

Wire cut surface

Bending strength
Small
Small
Small
Large

Wear resistanceP/M HSS

Ground surface

Rough surface due to EDM worsening0

Rough surface due to EDM worsening

Example of bad surface roughness

DURO-SP

Feature 1

Impact value
Small
Small
Small
Large

With DURO-SP, V5 and V2,toughness decrease is small evenif surface roughness worsens

Example of surface treatment

Test method: Ogoshi type wear testing machine
Friction Length: 200 m
Final load: 6.3 kg
Friction speed: 2.86 m/s
Sample: 5×10×60 mm

Lubricant: None
Rotor: SCM435 (102 HRB)

DURO-SP3210μm

Micro Vickers Hardness (HV 0.3)

Nitriding + coating cross section

1Superior

Wear ratio (mm3/kgfvm) ×10-4

44% decrease 36% decrease

0

DURO-SPDURO-V5P/M HSS

Feature 2

DURO-SP and DURO-V5 have superior wear resistance

1400
1200
1000
800

DURO-SP

600
400
200
0

0.00.1

0.2

0.30.4

Distance from surface (mm)Mechanical properties
Steel grade
DURO-SPDURO-V5
DURO-V2Hardness(HRC)
64.062.062.0* Sample taken from F50 mm rolled material

Tensile strength(GPa)
2.7
2.5
2.6

Proof stress(GPa)
2.2
2.0
2.1

Compressive strength Young's modulus Modulus of rigidity
(GPa)
(GPa)
(GPa)
4.2
228
89
3.8
215
84
3.8
215
84

Poisson's ratio
0.28
0.28
0.28

Failure process
V Toughness with condition of surface wear

SuperiorToughness

DURO-SP and DURO-V5 are better against wear on die
1. DURO-SP has superior wear resistance so development ofunevenness due to wear is slow
2. DURO-V5 has great resistance to generation and expansion of cracks

M Condition after the same shot

DURO-V5

2. Difference in crack generation andresistance to expansion

Wear

Cracking Expansion

ChippingDURO-SP
Based on the conditions after the same shot usage (see M), the DURO-SP
has better wear resistance than P/M HSS so the wear is not as advanced(see 1 in diagram). Comparing toughness shown on the vertical axis, thetoughness of the DURO-SP is better than P/M HSS.
In addition, the DURO-V5 has both better wear resistance and toughness
than P/M HSS, as shown by the large difference in the toughness afterwear has advanced (see 2 in diagram).
This shows that the DURO-SP and V5 are tougher than P/M HSS for die.
The life of a die increases by as much as its toughness increases.

1. Difference in wear
resistanceP/M HSS

Wear on surface of die worsening
Surface wear advances as the number of shots increases

DURO-SP

68

Hardness (HRC)

Austenitizing temperature °C (°F)
66641200 (2192)
1180 (2156)
1160 (2120)
1140 (2084)
1120 (2048)
1100 (2012)

62
60
58

AsQ

540(1004)

560(1040)

580(1076)

600(1112)

Dimentional change rate (%)

Heat treatment conditions
0.20
Axial direction

0.15
0.10

Radial direction

0.05
0.00

Austenitizing temperature 1160°C (2120°F)

−0.05
−0.10

AsQ

Tempering temperature °C (°F)

Hardness (HRC)

6664

Austenitizing temperature °C (°F)

62601160 (2120)
1140 (2084)
1120 (2048)
1100 (2012)1080 (1976)

585654

AsQ

540(1004)

560(1040)

580(1076)

600(1112)

Dimentional change rate (%)

DURO-V564

Austenitizing temperature °C (°F)

6260581120 (2048)
1100 (2012)1080 (1976)

5654

AsQ

540(1004)

560(1040)

580(1076)

600(1112)

0.15

DURO-SPDURO-V5
DURO-V2

Requirement
For hardness and wear resistanceStandard
For toughness
Standard
For toughness
Standard

Axial direction

0.10
Radialdirection

0.05
0.00
−0.05
−0.10

Austenitizing temperature 1120°C (2048°F)
AsQ

540(1004)

560(1040)

580(1076)

600(1112)

0.20
Radial direction

0.15

Axialdirection

0.10
0.05
0.00
−0.05
−0.10

Tempering temperature °C (°F)
Steel grade

600(1112)

Tempering temperature °C (°F)
Dimentional change rate (%)

Hardness (HRC)

66580(1076)

0.20Tempering temperature °C (°F)

DURO-V2560(1040)

Tempering temperature (°C)

Austenitizing temperature °C (°F)
1200 (2192)
1160 (2120)
1120 (2048)
1160 (2120)
1140 (2084)
1100 (2012)

Austenitizing temperature 1100°C (2012°F)
AsQ

540(1004)

560(1040)

580(1076)

600(1112)

Tempering temperature °C (°F)
Tempering temperature °C (°F) × Cycles
600 (1112) × 3
580 (1076) × 3560 (1040) × 3560 (1040) × 2580 (1076) × 2550 (1022) × 2Hardness (HRC)
666461626062

Heat treatment conditionsV Salt bath heat treatment (example of standard conditions)
1160°C

580°C

A(s)

ACA(s)ACAC

T (min)Hot bathquenching
550°C

850°C

580°C

580°C

AC

1160°CDURO-SP

Until inside and outside
are uniform

Hot bathquenching
550°C

850°C

A(s)

A(s)

DURO-V5

560°C

560°C

AC

T (min)T (min)Until inside and outside
are uniformACAC

T (min)T (min)

DURO-SP and DURO-V5
up to 10 mm
up to 2/5 inch
80 to 190
60

Diameter or Thickness
Heating time A(s)Tempering time T (min)10 to 25
2/5 to 1
190 to 310
901100°C
Until inside and outside
are uniform

Hot bathquenching
550°C

850°C

25 to 50
1 to 2
8×D
120

50 to 75
2 to 3
7×D
120

75 to 100
3 to 4660 to 720
180

over 100over 4over 720
210550°C
ACA(s)

50 to 75
2 to 3520 to 720
150

DURO-V2550°C

ACA(s)

25 to 50
1 to 2310 to 520
120

ACT (min)

T (min)* D:Workpiece diameter or thickness [mm]DURO-V2
up to 10 mmup to 2/5 inch
12×D*
90

Diameter or Thickness
Heating time A(s)Tempering time T (min)10 to 25
2/5 to 1
10×D
90

75 to 100
3 to 46×D120

over 100over 45×D
120v Immersion time shall be extended if salt bath temperature falls

Point

V Vacuum furnace heat treatment (example of standard conditions)
1160°C (N2 purge)
×850°C A (min)×600°C 40 min
GC×30 min

DURO-SP
600°C
×30 min
GC20 min 20 min 10 min

T (min)

560°C
GC

GC

T (min)

DURO-V5

GC

580°C

580°C

580°C

850°C
×40 min1160°C (N2 purge)
×A (min)

560°C
GCT (min)20 min 20 min

10 minT (min)GCT (min)

DURO-SP and DURO-V5up to 10 mmup to 2/5 inch
up to 15
90

Diameter or Thickness
Heating time A (min)Tempering time T (min)660°C
×30 min

870°C×40 min

10 to 25
2/5 to 1
15 to 201201100°C (N2 purge)
×A (min)

75 to 100
3 to 430 to 35180

over 100over 4over 35
180

DURO-V2550°C
GC

10 min

50 to 75
2 to 325 to 30150

DURO-V2

GC550°C

20 min 20 min

25 to 50
1 to 220 to 25
150

70 min T (min)GC70 minPointT (min)Example of workpiece
dimensions (mm)Heating time A (min)Tempering time T (min)

5×10×50 mm
0.2×0.4×2 inch
5120F50×60
F2×2.361518055×65×200
2.2×2.6×820180v Cooling at quenching shall be done as quickly as possiblev Heating time shall not be excessively long
* Temperature increase and heating times are reference values only due to variations in heat processing furnace.

Unauthorized reproduction of these materials is prohibited.
L Information in this catalog may be changed without prior notice due to technical advancements or product developments. While care has beentaken to produce these materials, NACHI Fujikoshi accepts no responsibility for damages caused by misprints or omissions that may occur during
the publication of this catalog.
L Please note that the characteristics and values provided here are typical examples which may differ from the characteristics of the actual product.

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