Effect of Graphite Size and Matrix Structure on Hydrogen Embrittlement Properties in Ferrite-Pearlite Ductile Cast Iron

Abstract

When using metallic materials in hydrogen equipment, it is important to consider the issue of hydrogen embrittlement. By controlling the graphite state and microstructure of spheroidal graphite ductile cast iron, it is possible to modify its strength properties and create a material that is less susceptible to hydrogen embrittlement. In this study, we prepared ductile cast irons with different graphite sizes by adjusting the cooling rate during casting. Additionally, we tailored the matrix structure to either ferrite or pearlite through heat treatment and controlled the chemical compositions accordingly. Hydrogen absorption measurements and tensile tests were conducted on the hydrogen-charged ductile cast irons. The relationship between the microstructure and hydrogen absorption was investigated, and the hydrogen embrittlement in the tensile fractures of ductile cast iron was discussed.