Explanation: Killed steels: In killed steel, the Oxygen is removed completely. The solidification of such steels does not give gas porosity (blowholes). So Killed steels are those steels Which are deoxidized in the ladle with silicon and aluminium Killed steel contains more than 0.25% carbon and is denoted by symbol ‘K'. Killed steel is a type of steel from which there is practically no evolution of gas during solidification of the ingot after pouring, because of the complete deoxidation, and formation of pipe in the upper central portion of the ingot, which is later cut off and discarded. All alloy steels, most low-alloy steels, and many carbon steel are usually killed. The continuous casting billets are also killed. The essential quality criterion is soundness. Killed steel is characterized by a homogeneous structure and even distribution of chemical compositions and properties. Killed steel is produced by the use of a deoxidizer such as Al and a ferroalloy of Mn or Si However, calcium silicide and other special deoxidizers are sometimes used. Cast iron Cast iron is an alloy of iron, carbon and silicon and it is hard and brittle. Carbon content in CI may be within 2% to 4% and carbon may be present as free carbon or iron carbide Fe3C. In general, the types of cast iron are (a) grey cast iron and (b) white cast iron (c) malleable cast iron etc Semi –killed steel: Incompletely deoxidized steels containing some amount of oxygen which forms CO during solidification. This practice of lesser deoxidation is generally adopted for plain carbon steels. Rimming steel: Partially deoxidized or non- deoxidized low carbon steels evolving sufficient CO during solidification. These steels have good surface finish [ alt="F1 S.S M.P 18.07.19 D 3" src="//storage.googleapis.com/tb-img/production/19/07/F1_S.S_M.P_18.07.19_D%203.PNG" style="width: 234px; height: 155px;">