Abstract
The relation between the microstructure and the modulus of elasticity of cast iron has been studied. The modulus was measured by the flexure method, a mirror being used and the loading being increased step by step at the middle point of specimens held at two points. The results are as follows:
(1) The modulus of elasticity is changed mainly by the form and quantity of graphite contained in iron, and the value increases considerably as the form varies from flake to spheroid in grey iron, the concentrations of the common elements in it being held alinost the same in each iron.
(2) The increase in quantity of graphite having the similar form reduces the modulus of elasticity, and the rate of the decrease is smaller in nodular iron than in flaky iron.
(3) The changes of the modulus due to the nodule numbers of graphite, the structures of the matrix and the increase in the concentration of Si, are markedly smaller than those due to the form and quantity of the graphite.
(4) With the temperature rise, the modulus decreases at first slowly and then rapidly at about 300°C. The decreasing rate is large in flaky iron compared with those in malleable iron and nodular iron.
