big cast iron resin sand casting material :GG25 ,GG20 Grey cast iron 1, Description :Big cast iron parts2, Material : Grey cast iron GG20,GG253, Process: Green sand , red sand and resin sand moulding4, Weight: 20kgs - 10000kgs .5,Surface treatment: Sand blasting, zinc plating, anti-rust paiting , powder painting6,Machining : CNC machining, turning ,milling ,drilling ect. big cast iron