Dandong Foundry
About Us Casting Products Casting Workshop Machining Workshop Inspection Certificate Blog ArticlesContact Us
  Grey Cast Iron EN-GJL  
 

Gray iron, or grey cast iron, is a type of cast iron that has a graphite microstructure. It is named after the gray color of the fracture it forms.

It is used for housings where the stiffness of the component is more important than its tensile strength, such as internal combustion engine cylinder blocks, pump housings, valve bodies, electrical boxes, counter weights and decorative castings. Grey cast iron's high thermal conductivity and specific head capacity are often exploited to make cast iron cookware and disc brake rotors.

Structure

A typical chemical composition to obtain a graphitic microstructure is 2.5 to 4.0% carbon and 1 to 3% silicon by weight. Graphite may occupy 6 to 10% of the volume of grey iron. Silicon is important to making grey iron as opposed to white cast iron, because silicon is a graphite stabilizing element in cast iron, which means it helps the alloy produce graphite instead of iron carbides; at 3% silicon almost no carbon is held in chemical combination with the iron.

The graphite takes on the shape of a three-dimensional flake. In two dimensions, as a polished surface will appear under a microscope, the graphite flakes appear as fine lines. The tips of the flakes act as preexisting notches; therefore, it is brittle. The presence of graphite flakes makes the Grey Iron easily machinable as they tend to crack easily across the graphite flakes. Grey iron also has very good damping capacity and hence it is mostly used as the base for machine tool mountings.


Microstructure of Gray Cast Iron

Physical and Mechanical Properties

Item according to DIN EN 1561

Measure

Unit

EN-GJL-150

EN-GJL-200

EN-GJL-250

EN-GJL-300

EN-GJL-350

EN-JL 1020

EN-JL 1030

EN-JL 1040

EN-JL 1050

EN-JL 1060

Tensile Strength

Rm

MPA

150-250

200-300

250-350

300-400

350-450

0.1% Yield Strength

Rp0,1

MPA

98-165

130-195

165-228

195-260

228-285

Elongation Strength

A

%

0,3 – 0,8

0,3 – 0,8

0,3 – 0,8

0,3 – 0,8

0,3 – 0,8

Compressive Strength

σdB

MPa

600

720

840

960

1080

0,1% Compressive Strength

σd0,1

MPa

195

260

325

390

455

Flexural Strength

σbB

MPa

250

290

340

390

490

Schuifspanning

σaB

MPa

170

230

290

345

400

Shear Stress

TtB

MPa

170

230

290

345

400

Modules of elasticity

E

GPa

78 – 103

88 – 113

103 – 118

108 – 137

123 – 143

Poisson number

v

0,26

0,26

0,26

0,26

0,26

Brinell hardness

HB

160 – 190

180 – 220

190 – 230

200 – 240

210 – 250

Ductility

σbW

MPa

70

90

120

140

145

Tension and pressure change

σzdW

MPa

40

50

60

75

85

Breaking Strength

Klc

N/mm3/2

320

400

480

560

650

Density

g/cm3

7,10

7,15

7,20

7,25

7,30


 

Home Page  |  Casting Products  |  Contact Us

   © BORUI CASTING INTERNATIONAL LTD (DANDONG FOUNDRY) All Rights Reserved
   ADD: No.1-4-11, Jianshe Road, Qianyang Town, Donggang, Dandong, Liaoning, China 118301
   SITEMAP | China Foundry