China OEM Black Flat Head Self Tapping Screws - ISO7380 Hexagon socket screws with flat round head 8.8 10.9 12.9 Grade – Dashan

ISO7380 hexagon socket screw, a kind of hexagon socket screw, its head is flat round head, the middle is concave hexagon, called hexagon socket flat round head screw. ISO7380 flat round head hexagon socket screw is adopted the international standard ISO7380:1997, the standard specifies the thread specification from M3 — M16, performance grade 8.8, 10.9 and 12.9, belong to the high strength and high grade hex socket screw. Generally, the carbon content of carbon steel is used to distinguish low carbon steel, medium carbon steel, high carbon steel and alloy steel. 8.8, 10.9, 12.9 available in stock, other sizes can be customized.