ISO9001-2008 have be passed. cast iron and ductile iron StandardSizeTypeMaterialISO2531DN15-DN2000Elbow, Socket,Crosses, Tee, Cap,Flange Adaptor.Body: Ductile Iron EPDM RubberBolt: Stainless steel or brass EN545DN15-DN2000BS4772DN15-DN2000EN598DN15-DN2000 Hardnessmaximum≤250HB Proof Stressminimum≥300MPA Tensile Strengthminimum≥420MPA Elongationminimum≥5% Coating:Black Painting,Fusion bonded epoxy ...