The Effects of the Degree of Carbon Saturation and Sulphur on the Graphitization and Mechanical Properties of High Grade Cast Iron Annealed at Low Temperatures
The effects of the melting conditions and the relation between the degree of carbon saturation and sulphur on the low temperature annealing treatment were examined. The oxygen amounts in the chill-cast samples were analized. The annealing of the specimens was carried out at 500°, 550°and 600℃ for 6 hrs and then the specimens were cooled in a furnace. The results obtained are summarized as follows : (1) The amounts of oxygen in the specimens prepared by the reducing refining which contain from 0.02 to 0.05 per cent sulphur were from 9 to 35 p.p.m. and those of oxygen in the specimens prepared by the oxidizing refining which contain from 0.02 to 0.07 per cent sulphur were from 26 to 60 p.p.m. (2) In the various degree of carbon saturation, the rate of graphitization of specimens prepared by the reducing refining which contain 0.05 per cent sulphur is lowest and the mechanical properties of this specimens are best. Generally, the tensile strength and hardness of the specimens which were annealed at 600℃ for 6 hrs are much lowered with the increase in silicon content from 1.8 per cent silicon. (3) In both as-cast and annealed state, when comparison was made in a constant tensile strength and deflective load, the hardness of the specimens prepared by the reducing refining is lower, compared with that of the specimens prepared by the oxidizing refining. This means that the relative hardness of the former is lower than that of the latter. Therefore, it may be said that the quality of the former is superior.
- Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 17/18 51-51, 1965