Spheroidal graphite cast iron with excellent gas defect resistance

The present invention provides spheroidal graphite cast iron, which has excellent gas detect resistance such that there are few gas defects such as pinholes arising from free N and which has mechanical characteristics and machinability equal to or greater than in the past. Provided is spheroidal graphite cast iron with excellent gas defect resistance that comprises, in mass ratio, C: 3.3-4%, Si: 2-3%, P: 0.05% or less, S: 0.02% or less, Mn: 0.8% or less, Cu: 0.8% or less (not including 0), Mg: 0.02-0.06%, Ti: 0.01-0.04%, V: 0.001-0.01%, Nb: 0.001-0.01%, N: 0.004-0.008%, the balance essentiallycomprising Fe and unavoidable impurities. 本发明提供种球状石墨铸铁，其具有由游离N引起的针孔等气体缺陷少的优异的耐气体缺陷性，并具有现有技术同等以上的机械性能和切削性。具有优异的耐气体缺陷性的球状石墨铸铁，以质量比计，C：3.3～4％；Si：2～3％；P：0.05％以下；S：0.02％以下，Mn：0.8％以下；Cu：0.8％以下且不包括0；Mg：0.02～0.06％；Ti：0.01～0.04％；V：0.001～0.01％；Nb：0.001～0.01％；N：0.004～0.008％，余量实质上由Fe和不可避免的杂质构成。