431310 foundry laboratory 7 composition control and grahite cast iron

8/18/2019 431310 Foundry Laboratory 7 Composition Control and Grahite Cast Iron

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7 (Composition Control and Graphite Cast Iron)

1. 2. ( )

( )


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1. (Introduction)1.1 (Cast Iron)

4

o (White cast iron)o (Malleable cast iron)o (Grey cast iron)o (Ductile cast iron)

1.1.1 (Grey cast iron)

(Damping capacity)

(Pig iron)

(Graphite) (Cementite) [1] 1 ( )

1 [2]


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3 [1]o o o

2.5-4.0%

(Graphite-forming elements)

(Carbide forming elements)

1

1 Grey cast iron

• Type A graphite Inoculation Moderate

undercooling


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• Type B graphite (near-eutectic composition) , Eutecticcell , Type B graphite Low undercooling

• Type C graphite (Hyper eutectic castirons) Minimum undercooling

• Type D graphite Hypoeutectic Eutectic irons • Type E graphite Strongly hypoeutectic irons• Type D and E graphite

High undercooling

2 type A, type b), type C, type D, type E type N


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1.1.2 (Ductile cast iron)

40-70

kg/mm2

392-686 MPa 8-25% [1] (Ductile cast iron) (Nodular graphite or spheroidal graphite cast iron)

3 . . 1948 [3]

(Ce) (Mg) 3.5-3.8%

2.2-2.8% 2

3 Ductile cast iron

2 [1]• (Metallic phase as the matrix)

- -

• (Morphology and distribution of graph


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2 [4] JAPAN SPHEROIDAL GRAPHITE IRON CASTINGS JIS G 5502-1995

Mechanical properties of separately cast test sample Symbol of

grade Tensilestrength(N/mm2)

Yieldstrength(N/mm2)

Elongation (%)

Charpy absorption energy (Information reference) Test

Temp.(oC)

Mean valueof 3 pieces

(J)

Individual value (J)

Hardness(HB)

Matrixstructure

FCD 350-22 350 min. 220 min. 22 min. 23 ± 5 17 min. 14 min. 150 max. FCD 350-22L - - - 40 2 12 min. 9 min. - -FCD 400-18 400 min. 250 min. 18 min. 23 5 14 min. 11 min. 130 to 180 FCD 400-18L - - - 20 2 12 min. 9 min. - -FCD 400-15 - - 15 min. - - - - -

FCD 450-10 450 min. 280 min. 10 min. - - - 140 to 210 -FCD 500-7 500 min. 320 min. 7 min.- - - 150 to 230 Ferrite +pearlite

FCD 600-3 600 min. 370 min. 3 min- - - 170 to 270 Pearlite +ferriteFCD 700-2 700 min. 420 min. 2 min. - - - 180 to 300 Pea

FCD 800-2 800 min. 480 min.- - - -

200 to 330Pearlite ortemperedstructure

1.2

(Composition Control of the Melt) (Chemical composition)

Spectrometer

- 4 [6] 2%

( 2%) (% C.E.) % C.E.

% . .= % +% + %3 % C.E. 4.3 % C.E.

4.3


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Si

C Si

Si

(Flotation

C

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4 Phase diagram of Fe-C [6]

C.E. (Ductile i

Chilling

i (C.E. = 4.3 )

7

C

on) C.E.

10 – 40


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Si C.E. chilling( ) (nodularity) C.E. Si

Nodularity

5 [6]

(Pig iron)

Ferrosilicon (Innoculant) (Nodularizer)

1.3

• (Inoculation)

A


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Nodule count (Chill)

(Heterogeneous nucleus)

Degree of Supercooling Eutectic cell

-

Superseed 3 0.4-1.0

Chill - (Ca) , (Sr) , (Al) , ( Ba )

3 Superseed 75

Element ContentSi 73-78 %Sr 0.6-1.0 %Ca 0.10% maxAl 0.50% max

1.4

• (Inoculation)


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0.15

• (Magnesium Treatment)

1100 C

5.0-6.0 (Nodularizer) 4

protective atmosphere (Residual magnesium) 0.020 0.030 wt%

-

0.04-0.06 wt% Mg

0.015 wt% S 0.035-0.04 wt% Mg

Sandwich process 6 [1]


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1.5 1

4

E

5

E

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6 Sandwich process. [1]

(Si)

(Target composition)

ement Weight percentC 3.5Si 2.5

%C.E. 4.3

30 0.4%

ement Weight percentSi 73-78Sr 0.6-1.0Ca 0.10 (max)Al 0.5 (max)

11


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=0.4100 30 = 0.12 = 120

= 75100 120 = 90 120 Si 90

% = , 100 =90 30 1000 100 = 0.3% 120 (0.4%)

2.5 2.8 2.5- 0.3 2.2

2 30 (Mgtreatment) 6

6

Element ContentSilicon 44 - 48 %Magnesium 5.0 - 6.0 %Calcium 0.4 - 0.6 %Rare earth 0.25 - 0.4 %Aluminium 0.8 - 1.2 %Iron Balanced

% = % . . ..


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3 5

0.4 30

4 1) 1450 2) 6 3)

0.04-0.06 1.3

(0.4/100) x (30x1000 g.) = 120 (75/100) x 120 g. = 90

(90 g. x100)/(30 x 1000 g.) = 0.3

1.3 (1.3/100) x (30x1000 g.) = 390

(45/100) x 390 g. = 175.5 (175.5x100) / (30x1000 g.) = 0.585

0.3% + 0.585% = 0.885

2.5

2.5% - 0.885% = 1.615


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2. (Experimental procedure) 2.1

-

- - - - - - (Spectrometer)

2.2 - 30-35 1500

- Spectrometer

- 5

- 1450 – 1500 - 1280 – 1380

5 C Si Mn P S 2.5 - 4.0 1.0 - 3.0 0.2 - 1.0 0.002 - 1.0 0.02 - 3.0 - 4.0 1.8 - 2.8 0.1 - 1.0 0.01 - 0.10 0.01 - 0

-

-


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7 Sandwich process


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3. (Experimental results)

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4. (Discussion)

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5. (Conclusions)

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6. 6.1 What element is the most important for promoting graphitization

irons?

______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

6.2 What is the chief cause of the relatively low tensile strengths of gand higher tensile strength in ductile cast iron?____________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________

6.3 Explain the sandwich process.

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


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7 [1] 2536[2] International standard (ISO 185 First edition 1988-12-15)[3] Morrough H., William W.J., Journal of the Iron and Steel (1948)[4] http://www.ductile.org [5] http://www.thermoscientific.com/ecomm/servlet/productsdetail [6] J.R. Davis Davis & Associates, ASM speciality handbook Cast Irons, 1996

431310 foundry laboratory 7 composition control and grahite cast iron

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