Sand casting is a process for producing metal parts by pouring molten metal into a sand mould cavity. Key steps include making patterns to form the mould cavity, using various types of sand like green sand with moisture and clay, and testing properties of moulding sand. Special casting processes include shell mould casting, investment casting and lost wax process. Castings are inspected using visual, magnetic particle, dye penetrant and ultrasonic methods to find internal and surface defects.