How is the gate valve made

How is the gate valve made? The whole production process of gate valve, from raw materials to finished products, is introduced in detail 。The first step is model development, design and manufacture of molds; The second part is to make wax model; The third step is to make the wax mold into a wax shell, burn the shell, the fourth step is to melt the steel material elements at high temperature in proportion, the fifth step is to invert the liquid steel in the high-temperature furnace, cast the wax mold, the sixth step is Desanding, the seventh step is grinding, the eighth step is shot blasting, annealing, etc，