... steel, brass, aluminium 3.zinc plated,hdg,black carriage bolt Itemcarriage boltMaterial of carriage boltCarbon steel(,Q235,C1010,C1020,C1040,10b21,etc)Brass ... ss316,A2-70,A4-70,A4-80)Grade of carriage boltGB,ISO,DIN standard:grade4.8,grade8.8,grade10.9,grade12. ... 9ANSI,ASTM:grade2,grade5 grade8Finishing of carriage boltColoured zinc-plated(galvanized ...