... ISO,CE passed vaious size and materails quick delivery sand gravel pump impeller main features:1.high chrome alloy materials2. ... Aluminum Bronze, Malleable Iron etc.Process: Investment Casting, Sand Casting (Resin Sand Casting, Green Sand Casting), Permanent Casting, Die Casting, Centrifugal Casting, ... , Milling, Turning, Boring, Slating, Grinding,, NC/CNC Machining etc. sand gravel pump impeller