大断面铸件中心的变态石墨是过球化石墨，而不是球状石墨向蠕虫状石墨或片状石墨方向衰退的产物。

• The metamorphous graphite in the section center of heavy section S.G. iron castings is superspheroidal graphite, and not the product of degeneration along the direction from shperoidal graphite to vermicular or flake graphite.