Coating Raw Material Coating Type Uncoated Zinc plated Yellow zinc plated Zinc nickel Phosphate Raw Material Spring steel Stainless Steel A2 Stainless Steel A4 D1D2BS33,16,21,30,844,17,61,50,955,19,21,81,266,111,82,51,688,114,8321010,218,13,52,21212,221,142,51414,224,14,531616,227,453,51818,229,453,52020,233,6642222,535,9642424,540752727,543753030,548,2863333,555,21063636,558,2106