Pump body is also known as pump casing, pump shell. Water pump body is usually made by gray iron (grey iron) HT200 (ASTM NO.30, GG20, ISO200, FC200, GC200). We called it HT200 in Chinese standard.
Our foundry has made many types of pump bodies for water pumps manufacturers in Korea and USA. For the suitable casting process, we suggest to use the green sand for the outside surface, and use precoated resin sand for the inside surface. This process can keep the good inside surface and quality, and will keep the costs as low as possible.
Usually, the water pressure testing will be necessary for the pump casing, but the pressure testing only is a inspection method, the basic way to reach their requirements is to improve the casting quality. Good foundry, suitable casting process, strict quality control are the good guarantee.