WHY CONVERT TO DUCTILE IRON?
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Why Convert To Ductile Iron?

Designers are converting steel castings, forgings, and fabrications to Ductile Iron castings to gain the following benefits:
  • Improved strength to weight ratio
  • Better surface detail and finish
  • Improved machinability
  • Reduced machining allowance
  • Lower component cost
  • More strength per dollar
  • Reduced component weight

Many steel castings, forgings, and fabrications can be converted to Ductile Iron castings at lower cost with equal or superior performance.

Talk To A Ductile Iron Foundry Representative Today!

Designing Effective Castings

Learn More About
The Advantages of Ductile Iron

Effective castings are a product of Designers and Foundry Engineers working together.
  • Consult a foundry at an early stage of the design process.
  • Discuss the design advantages offered by castings.
  • Utilize the freedom of design and materials selection offered by castings.
  • Take advantage of near-net shape design.
  • Design for casting soundness and optimum stress distribution.
  • Design for optimum economy.
  • Specify the properties and quality required by your application.

Talk To A Ductile Iron Foundry Representative Today!

A free, 40 page booklet "A Design Engineers Digest of Ductile Iron" is currently available, as well as two new technical publications, "Conversions to Ductile Iron" and "The Ductile Iron Data Book". To obtain these books and a list of Ductile Iron Foundries, or to discuss how you can take advantage of Ductile Iron castings, contact the Ductile Iron Group, or any of its member companies.

The Ductile Iron Marketing Group
c/o Ductile Iron Society
15400 Pearl Road
Suite 238
Strongsville,, OH, 44136
(440) 665-3686
Fax (440) 878-0070

The Ductile Iron Marketing Group is a non-profit organization dedicated to increasing the understanding of the technical and economic advantages of Ductile Iron castings. The Members of the Ductile Iron Marketing Group are:

The Ductile Iron Society
Rio Tinto Iron and Titanium
Miller and Company

Physical Properties of Ductile Iron and Alternative Materials

Property

Unit

Ductile Iron

0.3% C
Cast Steel

Malleable Iron

Gray
Iron*

120-90-02

100-70-03

80-55-06

65-45-12

60-40-18

Solidus Temperature

°F

2,100

2,100

2,100

2,100

2,100

2,650

2,050

2,140

Specific Gravity

lb/in³

0.25

0.25

0.25

0.25

0.25

0.283

0.265

0.25

Mean Linear
Thermal Expansion

°F-¹
x 10
to the -6th

6.0

6.0

6.0

6.0

6.0

7.0

6.7

5.8

Vibration Damping

-

Good

Good

Good

Good

Very Good

Poor

Good

Excellent

Heat of Fusion

BTU/lb

55

55

55

55

55

108

55

55

Specific Heat

BTU/lb/°F

0.15

0.15

0.14

0.13

0.13

0.11

0.12

0.13

Thermal Conductivity (near room temperature)

Cal/cmsec °C

0.06

0.06

0.08

0.09

0.10

0.11

0.14

0.11

Magnetic Properties

Maximum Permeability at 5,000 Gauss

Oersted

290

290

570

2,100

2,100

-

2,350

800

Saturation Induction at 10,000 Oersted

Gauss

-

-

17,600

18,000

18,000

-

-

16,000

Hysteresis Loss

Erg/cm³/cycle

-

30

30

5

5

100

20

30

Mechanical Properties

Proof Stress

psi

(0.62 to 0.75) x Ultimate Tensile Strength

30,500

(0.65-0.8)
x UTS

-

Modulus of Elasticity
in Tension

psi x 10 to the 6th

25.7

25.7

25.2

23.8

23.8

30.5

25

18.3

Torsional Strength

psi

108,000

90,000

72,000

58,000

50,000

-

34,000

60,000

Modulus of Rigidity

psi x 10 to the 6th

9.6

9.6

9.6

9.3

9.1

11.4

11

7.1

* A medium-high strength gray iron was selected for comparison purposes.

Short Summary of Ductile Iron Specifications

Specifying Body

Spec. No.

Class or Grade

Min. Tensile psi

Min.
Yield psi

% Elongation

Heat Treatment

Other Requirements

Uses

Typical Applications

ASTM

A536-80

60-40-18

60,000

40,000

18

May be Annealed

In all grades in this specification chemical composition is subordinate to mechanical properties. However, the content of any element may be specified by mutual agreement. For maximum shock resistant parts to be used at sub-zero temperatures. Pressure-containing castings such as valve and pump bodies.

ASTM

A536-80

65-45-12

65,000

45,000

12

-

Most widely used grade for normal service. Machinery castings subject to shock and fatigue loading.

ASTM

A536-80

80-50-06

80,000

55,000

6

-

Suitable for flame and induction hardening. Crankshafts, gears and rollers.

ASTM

A536-80

100-70-03

100,000

70,000

3

Usually Normalized

Best combination of strength, wear resistance and response to surface hardening. High strength gears, automotive and machine components.

ASTM

A536-80

120-90-02

120,000

90,000

2

Quenched and Tempered

Maximum strength and wear resistance. Pinions, gears, rollers and slides.

 

Short Summary of Austenitic Ductile Iron Specifications

Specifying Body

Spec. No.

Class or Grade

Min. Tensile psi

Min. Yield psi

% Elongation

Heat Treatment

Chemical Analysis and Hardness

Typical Applications

% T.C.

%
Si

%
Mn

%
P

%
Ni

%
Cr

BHN

ASTM A439-84

D-2

58,000

30,000

8

Min.

1.50

0.70

18.00

1.75

139

Valve stem bushings, valve and pump bodies in petroleum, salt water and caustic service, manifolds, turbocharger housings, air compressor parts.

Max.

3.00

3.00

1.25

0.08

22.00

2.75

202

D-2B

58,000

30,000

7

Min.

1.50

0.70

18.00

2.75

148

Turbocharger housings, rolls.

Max.

3.00

3.00

1.25

0.08

22.00

4.00

211

D2-C

58,000

28,000

20

Min.

1.00 1.80 21.00

121

Electrode guide rings, steam turbine dubbing rings.

Max.

2.90

3.00

2.40

0.08

24.00

0.50

171

D-3

55,000

30,000

6

Min.

1.00

28.00

2.50

139

Turbocharger nozzles and housings, steam turbine diaphragms, gas compressor diffusers.

Max.

2.60

2.80

1.00

0.08

32.00

3.50

202

D-3A

55,000

30,000

10

Min.

1.00

28.00

1.00

131

High temperature bearing rings requiring resistance to galling.

Max.

2.60

2.80

1.00

0.08

32.00

1.50

193

D-4

60,000

Min.

5.00

28.00

4.50

202

Diesel engine manifolds, manifold joints.

Max.

.60

6.00

1.00

0.08

32.00

5.50

273

D-5

55,000

30,000

20

Min.

1.00

34.00

131

Guidance system housings, gas turbine shroud rings, glass rolls.

Max.

2.40

2.80

1.00

0.08

36.00

0.10

185

D-5B

55,000

30,000

6

Min.

1.00

34.00

2.00

139

Optical system mirrors and parts for dimensional stability, stators for compressors.

Max.

2.40

2.80

1.00

0.08

36.00

3.00

193

D-5S

65,000

30,000

10

Min.

4.90

34.00

1.75

131

Manifolds, turbine housings, turbochargers where high temperatures and severe thermal cycling occur.

Max.

2.30

5.50

1.00

0.08

37.00

2.25

193

ASTM

A571-71 (1976)

D-2M

65,000

30,000

30

Annealed

Min.

2.20

1.50

3.75

21.00

121

Compressors, expanders pumps and other pressure-
containing parts requiring a stable austenitic matrix at minus 423F (-234C)

ASME

SA571

Max.

2.70

2.50

4.50

0.08

24.00

0.20

171

Short Summary of
ASTM Specification A897-90 / A897M-90 For Austempered Ductile Iron
Grade Min. Tensile Strength

Min. Yield Strength

Elongation Percent Impact Energy* Hardness BHN**

MPa

Ksi

MPa

Ksi

Joules

Ft-lb

125/80/10

125

80

10

75

269-321

850/550/10

850

550

10

100

269-321

150/100/7

150

100

7

60

302-363

1050/700/7

1050

700

7

80

302-363

175/125/4

175

125

4

45

341-444

1200/850/4

1200

850

4

60

341-444

200/155/1

200

155

1

25

388-477

1400/1100/1

1400

1100

1

35

388-477

230/185/-

230

185

***

***

444-555

1600/1300/-

1600

1300

***

***

444-555

* Values obtained using unnotched Charpy bars tested at 72° F (2° C). The values in the table are the
average of the three highest of four tested samples.
** Hardness is not a mandatory specification and is shown for information only.
*** Elongation and impact specifications are not required.

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