DIN7991 nail head can be buried in the member, joint strength, the head with hexagonal wrench twist. Installation requires a countersunk hole, can keep the surface of the workpiece flat, beautiful, commonly used in machinery, easy to fasten, disassemble, not easy to slip angle and other advantages.
DIN7991钉头可埋入构件内，联接强度大，头部用内六角扳手拧动。安装的时候需要打一个沉孔，可保持工件表面的平整、美观，常用于机械上，易于紧固、拆卸，不容易滑角等优势。





DIN912 head is cylindrical with knurling, the center is concave hexagonal, the head can be buried in the component, can apply a greater torque, connection strength is higher, commonly used in the structure requires compact, smooth appearance of the joint, mainly used in electronics, electrical appliances, electrical, electric power, chemical industry, water conservancy, machinery and equipment, furniture and other fields.
IN912头部是圆柱状的带有滚花，中间是凹进去的六边形，头部能埋入构件中，可施加较大的扭矩，连接强度较高，常用于结构要求紧凑，外观平滑的联接处，主要运用于电子、电器、电气、电力、化工、水利、机械设备、家具等领域。




ISO7380 head is flat round head, the center is concave hexagonal, known as hexagon socket flat round head screws, the head can be buried in the parts countersunk holes, smooth shape, compact structure. Hexagon can withstand greater tightening torque, high joint strength, can replace the use of hexagon head bolts, generally used in flat surfaces, mostly used for protection of doors, windows, etc. fixed.
ISO7380的头部是平圆头的，中间是凹进去的六边形，称为内六角平圆头螺钉，头部可埋入零件沉孔中，外形平滑，结构紧凑。内六角可承受较大的拧紧力矩，联接强度高，可替代六角头螺栓使用，一般用于平面上，多用于防护门、窗的固定等。