Abstract
For researching the properties of cast iron, we had investigated the relation between O2 content, mechanical strength and graphite structure, and reasoned "Virginity" of pig iron would have a strong effect on the properties of cast iron, which has been commonly believed but its cause has not been found. Recently, it is considered that its causing subject may be dissolved gases (O2 H2 and N2) and minute oxides. So, chemical composition, dissolved gases—H2 and O2—in pig and cast iron were analyzed and the effect of these factors on mechanical strength, graphite structure and castability were also studied. The results obtained were as follows : 1. H2 and O2 content in pig iron exerted influence on iron casting properties and increased by the production method-raw materials and fuels-as follows. [m. s. scrap] ･ [coke] < [ore] ･ [charcoal] < [ore] ･ [coke] 2. Repeated shock value of cast iron was severely influenced by graphite structure. 3. Swedish, Ogure and Arisa pig iron showed good results.
