Influence of Sulfur on the Microstructure and Properties of High Nickel Austenite Grey Iron

Abstract

The influence of sulfur on the microstructure and properties of austenite grey iron with 14-16% Ni was studied. The results showed that the crystallizing temperature of primary austenite increases and the the eutectic temperature does not changes greatly with addition of sulfur. When the content of sulfur is lower than 0.046%, the undercooled graphite existed mainly, the hardness of austenite grey iron and the sensibility of cross section become higher. When the sulfur increases to 0.08%, the A type of flake graphite distributed mainly, and the hardness and the sensibility of cross section reaches the lowest. When the sulfur is over 0.11%, the dentritic primary austenite developed largely, the space interval of austenitic dentrite reduced, and a large amount of interdentritic graphite formed, and the hardness and the sensibility of cross section increased again. In additon, the surface roughness of machined casting is influenced by the morphology of flake graphite.