Abstract
The authors measured the O2, N2 and H2 contents in cast iron by means of the vacuum fusion gas analysis equipment to determine how much these gas contents were influenced by melting conditions. Several tests were also performed on molten metals from a cupola or an electric furnace with the following conclusions:— 1. Up to 1450°C under the condition of crucible - melting in the laboratory, rise of the melting temperature is attended with an increase of O2, N2 contents : further rise over 1500°C, on the contrary, will result in a decrease of both elements. 2. In the cupola or electric furnace, high temperature operation over 1500°C will also reduce the amounts of O2, and N2. In comparison with crucible melting in the laboratory, the H2 content is very large. 3. Relationship among the microstructure, graphitization degree, hardness of castings and analysis value of O2 is to be still further studied for clarification. 4. Characteristics of low-temperature and high-temperature melting were investigated with regard to deoxidation of molten cast iron. As a result it is pointed out that in low-temperature operation, effects of rusted charging materials and oxidized layers growing before the melt-down are hard to eliminate, but in high temperature working, the O2 content approaches the deoxidation equilibrium value and at the same time molten metals tend to be very liable to absorb H2.
