Flat head machine screws 1,Products DetailesMaterial1.Stainless Steel ... C37700 ( HPb59), C38500( HPb58), C27200CuZn37), C28000(CuZn40)4.Bronze: C51000, C52100, C54400, etc5.Iron: 1213, ... ,BSWManufacture ProcessHeading/washer assembly/Threading/Secondary machine/heat treatment/plating/Anti-slipping/Baking/ ... Factory overview 3, Warehouse and Workshop show 4,Manufacture Process 5,Quality Control 6, Strong ...