Question

A hemispherical shell with an external diameter of 500 mm and a thickness of 20 mm is going to be made by casting, located entirely in the upper part of the corresponding mold, with the maximum circle on the partition surface. If the density of the molten metal is 7.2 g / cm3 and the height of the pouring cavity above the partition surface is 300 mm, determine the metallostatic thrust that will be exerted on the upper mold at the end of casting.

Answer 1

Solution :

Given :

External diameter of the hemispherical shell, D = 500 mm

Thickness, t = 20 mm

Internal diameter, d = D - 2t

                                 = 500 - 2(20)

                                 = 460 mm

So, internal radius, r = 230 mm

                                 = 0.23 m

Density of molten metal, ρ = $7.2 \ g/cm^3$

                                                  = $7200 \ kg/m^3$

The height of pouring cavity above parting surface is h = 300 mm

                                                                                                  = 0.3 m

So, the metallostatic thrust on the upper mold at the end of casting is :

$F=\rho g A h$

Area, A $=2 \pi r^2$

            $=2 \pi (0.23)^2$

            $=0.3324 \ m^2$

$F=\rho g A h$

   $=7200 \times 9.81 \times 0.3324 \times 0.3$

     = 7043.42 N