Hexagonal bolts, also known as hexagonal head bolts, are a type of connecting element widely used in the fastener industry. They consist of a head and a screw (a cylinder with external threads), and are usually used in conjunction with a nut to fasten two parts with through holes.

The performance grade of carbon steel for hexagonal bolts ranges from 3.6 to 12.9, of which bolts above 8.8 are generally called high-strength bolts. Stainless steel ranges from 500MPA to 800MPA, and these performance grades represent the nominal tensile strength of the bolt material and its yield strength ratio.

The main standards for hexagonal bolts are GB/T 5782/GB5783, ISO4014/ISO4016, DIN933/DIN931, etc.

Common surface treatments for hexagonal bolts include electroplating, blackening, hot-dip galvanizing, etc., which are intended to improve their corrosion resistance and aesthetics. Different surface treatment technologies, such as acid tin plating and alkaline tin plating, have their own advantages and disadvantages, and the selection should be based on the specific application environment.