... smooth. 4)International Quality 1 Material:Gray cast iron GG15/GG20/GG25 or ductile cast iron2 Weight: 0.05-50kg3 Surface: Black ... processing and then precision machined.OEM/ODM parts range:Auto parts,electronic parts,motor shell, pump parts,machinery parts,light fittings,dental equipment,medical cases etc ... have your samples and design to producing for you. Gray Cast Iron Machinery Parts,sand casting ...