# Design of gating system for shell steel castings

According to the selection principle of parting surface, two casting process schemes are preliminarily designed. The first process scheme designs the inner runner at the base of the steel casting, as shown in Figure 1; The second process scheme places the inner runner on the cylindrical part of the steel casting, as shown in Figure 2. The two processes are simple and easy to operate. As the casting is a steel casting, the gating system adopts an open gating system. The advantages of this gating system are smooth filling, avoiding turbulence and reducing the oxidation of molten metal.

The bottom plug rod ladle is used for pouring, and the hole diameter is 40mm. According to the casting process manual, the average flow rate of the pouring hole is 27kg/s. The pouring time is calculated according to the formula:

Where: t is the pouring time; GL is the mass of molten steel in the mold, GL=450kg; N is the number of pouring bags simultaneously, N=1; N is the number of pouring holes in a ladle, n=1; Q is the average pouring speed.

According to the formula, t=16.7s. Whether the pouring time is appropriate can be checked by the rising speed of molten steel in the mold, see the formula:

Where: v is the rising speed of molten steel in the mold; C is the height of the steel casting in the mold cavity, C=356mm; T is the pouring time, t=16.7s.

According to the formula, the rising speed of molten steel in the mold is 21.3mm/s.

The sectional area of each component of the selected gating system is shown in the formula:

Hole diameter Φ＝ 40mm, according to formula (3), ∑ A resistance=1256mm2; ∑ Within A=2763mm2; Σ A straight=2386 mm2, Φ Straight=55mm.