a method of one - piece casting of a tool with a working component of steel and a body of grey iron , and an interconnection zone therebetween is carried out in a single mould which is kept closed and unchanged during the casting . the steel is cast first from beneath and upwards , whereafter a pause is made . the casting of the grey iron is only carried out when the temperature of the steel in the intended interconnection zone has fallen to a temperature corresponding to the liquidus temperature of the steel minus approx . 30 ° to 150 ° c .