Determination of cross section size of each component of casting parts of support platform

The section size of each component can be obtained by simple empirical formula according to the type, quality, size, wall thickness and casting time of casting alloy.

In production, the minimum cross-sectional area of the internal sprue is 0.04cm2, and the minimum diameter of the direct sprue is generally not less than 15-18mm.

Calculation formula of flow resistance section of gray cast iron:

——Total area of the minimum section in the gating system (cm2);

M — total weight of liquid metal flowing through f resistance section (kg);

μ – total flow loss coefficient;

——Pouring time (s);

——Average static head (CM)

In the formula, M is 8.6kg; μ = 0.42 [3]; = 110cm;

The pouring time is calculated as follows:

M – total mass (weight) of metal liquid in the mold (kg)

—Coefficient, depending on the wall thickness of the casting, it is found from the table that = 2.2 [3].

The pouring time is 6.5s.

As the parts of the support table are small and medium-sized castings, the section ratio is determined to be 1:1.1:1.15.

According to the calculation formula of the flow resistance section, the cross-sectional area of the internal sprue is 8.90, and it is found from the table that a = 56mm, B = 52mm

, C = 17mm; section area of sprue = 10.24, d = 18mm according to the table; section area of transverse sprue = 9.97, a = 32mm, B = 22mm, C = 35mm. Therefore, the schematic diagram of each sprue of the supporting platform parts is as follows:

Sectional area of internal sprue, direct sprue and cross sprue

Table 1 standard values of gating system for gray iron castings

Internal sprue size/mm

(S(in)/m㎡ )

Runner size/mm

(S(tr)/m㎡

Sprue size/mm

(S(str)/ m㎡)

a

b

c

S(in)

a

b

c

S(in)

A

B

C

S(tr)

D

S(str)

11

9

5

50

6

4

10

50

16

11

18

240

17

230

14

12

6

80

8

5

12

80

19

14

22

360

20

310

18

15

7

115

10

6

15

120

23

15

25

480

23

420

20

18

8

150

11

7

17

150

28

18

31

720

27

570

24

21

10

225

13

9

21

225

32

22

35

950

32

800

30

26

11

310

14

10

26

310

38

28

42

1380

38

1130

40

30

12

455

17

11

33

450

46

32

50

1950

45

1590

45

41

14

600

20

12

37

600

56

40

58

2800

53

2200

56

52

17

920

24

16

46

920

65

45

70

3850

65

3320

58

53

22

1200

28

20

50

1200

80

60

80

5600

80

5030

Riser and size determination

Generally small castings with uniform wall thickness may not have riser, so it is omitted here.

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