Analyzing the Failure of Master Mould in Casting of Copper Anode Moulds and Suggesting a more Suitable Metal Mould

Master moulds are used to cast copper anode moulds. These iron moulds are made of grey or nodular cast irons. According to desirable properties of ductile irons, it was expected that ductile cast iron moulds could have performed their nominal life. But in service, these moulds have not performed their nominal life and they have experienced premature failures due to warping and cracking. Also grey cast iron moulds fail because of generalized surface cracks. In this paper, the failure of master moulds is investigated according to the metallographic and hardness measurement tests. Then pearlitic and austempered ductile iron alloys are proposed and tested through short time high temperature tensile and thermal shock tests with respect to working conditions of the moulds. Also master mould is modeled by Finite Element Method to evaluate the thermal conditions. Finally it is concluded that compared with pearlitic ductile iron, austempered ductile iron has higher resistance to thermal shock.