... high quality iron,such as 1022,1018,1010,1008,1015...Medium carbon steel are 35k,45#,10B21,1035,CH38F,1039, ... customer's demand .Threads/ScrowsType "M","UNC","UNF","BSW"thread are available. Head typesHexagon head,Mushroom head,Pan head,Countersunk ... several New quality control equipments had brought to Enhance the strength of the quality control .3.Certificate:Provide dimensions report,chemical ...