OEM large cast iron casting parts 1. High intensity and rigidity 2. Strict quality control OEM large cast iron manhole covers DescriptionMaterialTechnical ProcessDuctile ironcastingsASTM A 536-Gr.60-40-18,etcDIN GGG40,GGG50,700-2,etcJIS FCD40,FCD50 etcBS Gr370-17,Gr420-12,etcGreen-sand mouldingResin-sand mouldingLost foam castShell-core castElectric-furnace smeltingGrey ironcastingsASTM A48-No.20 ...