Abstract
From the thermal analysis curves and microscopic structures of gray iron containing molybdenum and copper, it was concluded that the matrix structure depends upon the cooling rate within the temperature range of austenite and the amounts of alloying elements.
After adding molybdenum and copper to molten pig iron in a cupola, it was poured into a sand mould with four steps (10, 20, 30 and 40 mm in dia. respectively and 200 mm in total length). By microscopic observations on the matrix structures and hardness measurements, the structural diagram for acicular cast iron having a Brinell hardness of 240∼280 was determined.
