Abstract: Experimental investigation is made on primary factors affecting the permeability of grey cast iron with the help of an original permeability tester. On the basis of the results it is obtained that the path constituted by graphite and crack is the principle way of leakage. It is beneficial to the improvement of permeability of grey cast iron to ameliorate graphite form, reduce carbon equivalent on condition that compact structure is available, add right content of alloying elements, chromium and copper, increase cooling rate.

Key words: Grey cast iron, Leakage, Permeability