Sand Casting, Investment Casting and Die Casting in China

Grey Cast Iron Property and Chemical Composition

Grey Cast Iron (Gray iron castings) is so called because of the colour of the fracture face. It contains 1.5-4.3% carbon and 0.3-5% silicon plus manganese, sulfur and phosphorus. It is brittle with low tensile strength, but is easy to cast.

The all data in this documents is referred to Chinese standard of GB/T 9439-1988. Qingdao Casting Quality Ind write all materials from handbook.—www.castingquality.com—

grey cast iron composition.pdf —www.castingquality.com—

Single Casting Specimen Tensile Strength Property —www.castingquality.com—

Gray Iron Grade

Single Specimen

Tensile Strength

σb≥/Mpa

Gray iron Castings

Wall Thickness

/mm

Tensile Strength

σb≥/Mpa

HT100

100

>2.5~10

>10~20

>20~30

>30~40

130

100

90

80

HT150

150

>2.5~10

>10~20

>20~30

>30~40

175

145

130

120

HT200

200

>2.5~10

>10~20

>20~30

>30~40

220

195

170

160

HT250

250

>4.0~10

>10~20

>20~30

>30~50

270

240

220

200

HT300

300

>10~20

>20~30

>30~50

290

250

230

HT350

350

>10~20

>20~30

>30~50

340

290

260

Castings Attached Specimen Tensile Strength Property—www.castingquality.com—

Gray Iron Grade

Wall Thickness

/mm

Tensile Strength σb≥/Mpa

Tensile Strength (reference)

σb≥/Mpa

Attached Test Coupon

Attached Test Block

φ30mm

φ50mm

R15mm

R25mm

HT150

>20~40

>40~80

>80~150

>150~300

130

115

-

-

-

(115)

105

100

120

110

-

-

-

-

100

90

120

105

90

80

HT200

>20~40

>40~80

>80~150

>150~300

180

160

-

-

-

(155)

145

135

170

150

-

-

-

-

140

130

165

145

130

120

HT250

>20~40

>40~80

>80~150

>150~300

220

200

-

-

-

(190)

180

165

(210)

190

-

-

-

-

170

160

205

180

165

150

HT300

>20~40

>40~80

>80~150

>150~300

260

235

-

-

-

(230)

210

195

(250)

225

-

-

-

-

200

185

245

215

195

180

HT350

>20~40

>40~80

>80~150

>150~300

300

270

-

-

-

(265)

240

215

(290)

260

-

-

-

-

230

210

285

255

225

205

Grey Iron Castings’ other  mechanical property—www.castingquality.com—

Grade

Compressive Strength

σbc/MPa

Shearing Strength

τb/Mpa

Impact Testing

αKV/(J/cm2)

Safe Range of stress

σ-1/MPa

Modulus of Elasticity

Ε/GPa

HT150

500~700

150~250

-

60~90

70~90

HT200

600~800

200~300

2~5

80~90

80~110

HT250

800~1000

250~350

4~8

100~140

100~130

HT300

1000~1200

300~450

7~10

120~160

120~140

HT350

1100~1300

350~500

9~11

140~180

130~160

Grey Iron Castings Hardness

Gray Iron Grade

Hardness Grade

Hardness Range

HB

Metallography

HT100

H145

≤170

Ferrite

HT150

H175

150~200

Ferrite + Pearlite

HT200

H195

170~220

Pearlite

HT250

H215

190~240

Pearlite

HT300

H235

210~260

Pearlite(Inoculated Cast Iron)

HT350

H255

230~280

Pearlite(Inoculated Cast Iron)

Gray Iron Casting heat treatment—www.castingquality.com—

Casting Unit Weight

kg

Starting Temperature

/οC

Heating Speed

/(οC/h)

Preservation Temperature/οC

Heat Preservation Time

/h

Cooling Speed

/(οC/h)

Final Temperature

/οC

Cast Iron

Low Alloy Cast Iron

Simple Castings

<200

≤200

≤100

500~550

550~570

4~6

30

200

200~2500

≤200

≤80

500~550

550~570

6~8

30

200

>2500

≤200

≤60

500~550

550~570

8

30

200

Precision Castings

<200

≤200

≤100

500~550

550~570

4~6

20

200

200~2500

≤200

≤80

500~550

550~570

6~8

20

200

Gray Iron Casting, no any standard mentioned the chemistry composition, so we only suggest the following chemistry based on actual production.—www.castingquality.com—

Grade

Wall Thickness

/mm

C

Si

Mn

P

S

HT100

-

3.4~3.9

2.1~2.6

0.5~0.8

0.3

0.15

HT150

<30

30~50

>50

3.3~3.5

3.2~3.5

3.2~3.5

2.0~2.4

1.9~2.3

1.8~2.2

0.5~0.8

0.5~0.8

0.6~0.9

0.2

0.2

0.2

0.12

0.12

0.12

HT200

<30

30~50

>50

3.2~3.5

3.1~3.4

3.0~3.3

1.6~2.0

1.5~1.8

1.4~1.6

1.7~0.9

0.8~1.0

0.8~1.0

0.15

0.15

0.15

0.12

0.12

0.12

HT250

<30

30~50

>50

3.0~3.3

2.9~3.2

2.8~3.1

1.4~1.7

1.3~1.6

1.2~1.5

0.8~1.0

0.9~1.1

1.0~1.2

0.15

0.15

0.15

0.12

0.12

0.12

HT300

<30

30~50

>50

2.9~3.2

2.9~3.2

2.8~3.1

1.4~1.7

1.2~1.5

1.1~1.4

0.8~1.0

0.9~1.1

1.0~1.2

0.15

0.15

0.15

0.10

0.10

0.10

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Sand Casting, Investment Casting and Die Casting in China