Observation of pearlite-ring and graphite particles in decarburized spheroidal graphite cast iron

Abstract

Spheroidal graphite cast irons, which are referred to as FCD materials in the Japanese Industrial Standard (JIS), are often used for automotive parts. This is due in part to their net shape castability and relatively low cost. When welded, however, they show serious drawbacks, particularly brittle fracture due to chilling of excess carbon in the matrix. This study looks at decarburized spheroidal graphite cast iron (FCD-D material), which is more suitable for welding. In this study, heat treatment for decarburization was conducted by a solid decarburizing method for 86.4 ~ 345.6ks at 973 ~ 1373K to produce a decarburized layer on the surface of the FCD cast iron parts.In the decarburized layer of the cast iron parts, a ring-like pearlite layer, voids and decarburized spheroidal graphite particles were observed. In this study, we have investigated the evolution behaviour of the decarburized layer, the pearlite-ring and the decarburized spheroidal graphite particles during the decarburization.