... BS, JIS, NF, AAR Investment Casting of Suspension Parts for Trailers 1.Quality system certificate: ISO 90002. Standard: ... Steel , Alloy Steel, Stainless Steel, Gray Iron, Ductile Iron, Aluminum, ect . 10. Surface Treatment: Heat Treatment, Machine, Polishing, ... Plating 11.These parts are used in machine assembly, valve &pump parts, auto &motorcycle parts, train & railway parts, marine hardware, ...