Die Steels & Die Cast
Steels:
DH31 Super
High strength,
tough and high heat check resistance hot work die steel.
DH31-S is a hot working die steel with the
best balance of strength and toughness showing the comparable softening
resistance to SKD7 and twice hardenability as that of SKD61.
FEATURES
-
High
hardenability
High toughness is obtained even in large size die.
-
High
strength
High softening resistance at elevated temperature contributes to
high wear resistance.
-
High
toughness
DH31-S has higher toughness than that of SKD61.
-
High
heat check resistance
Excellent heat check resistance leads to longer life.
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APPLICATIONS
- Aluminum die cast dies especially for
large size - long life use
- Aluminum die cast parts such as pins and
plunger sleeve
- Hot forging dies
- Hot pressing dies
- Aluminum extrusion dies
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EXAMPLES
OF APPLICATION

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CHEMICAL
COMPOSITION

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THE
CONCEPT OF DEVELOPMENT
DH31-S is a hot working die steel with the
best balance of strength and toughness showing the comparable softening
resistance to SKD7 and twice hardenability as that of SKD61.

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HARDENABILITY
High toughness is obtained even in large
size dies due to high hardenability.
- Continuous cooling transformation
curve

- Bainite hardenability
As Bainite transformation starting time is twice as that of SKD61,
130min., quenching operations is easily and safely carried out without
troubling such as toughness deterioration in large size dies.

- Quenching cooling time vs. toughness

Cooling time of mid portion from 1030°C to 300°C (min)
- TP size: Ø440
- Quenching temp: 1030°C
CHARACTERISTICS
- Tempering hardness

- Quenching temp: 1030°C
- T.P. size: 10H x 10W x 15L
- Toughness

- Quenching temp: 1030°C x 30min. -->
150 Dia. Bar, AC
- T.P. size: L
- Softening resistance

- Holding temp.: 600°C
- Quenching temp: 1030°C x 30min. -->
150 Dia. Bar, AC
- T.P. size: 10H x 10W x 15L
- Elevated temperature tensile
properties
Heat check resistance is further
improved by increasing hardness without deteriorating toughness.
An example to improve heat check
resistance (200mmm thickness air cool quenched die)

<Test procedures>
- Specimen: 15mm
- I/Heating: 20<-> 700C
- Number of cycles: 1000 times
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- Erosion resistance

- Creep properties

SURFACE
HARDENING PROPERTIES
- PS, PW process
- Daido Amistar's originally
developed process.
- PW process improves wear,
fatigue and corrosion resistance.
- PS process improves scuffing
and erosion resistance.
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MACHINABILITY
- DH31-S shows good
machinability as high strength-high tough grades.
- Recommended machining conditions

HEAT
TREATMENT CONDITIONS

REPAIR
WELDING CONDITIONS
- TIG manual welding condition

PHYSICAL
PROPERTIES
Coefficient of thermal expansion

Thermal conductivity

Specific heat

Density
US Contact:
International Mold Steel, Inc.
6796 Powerline Drive
Florence, KY 41042 USA
Tel: (859) 342-6000 or 1-800-625-6653
Fax: (859) 342-6006
Email: info@imsteel.com
Web: www.imsteel.com
www.daido.co.jp
IMPORTANT NOTE
Please be advised that Daido Steel shall not be held responsible for
damage caused by misunderstanding or improper use of the technical
information contained in this brochure. The contents of this brochure may
be subject to change without notice. Please inquire of related department
for the latest infromation. No portion of this brochure may be reproduced
without express permission of Daido steel.
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