Blackened hexagon socket bolts (without knurling) are a common fastener. Blackened hexagon socket bolts are available in various sizes. Their nominal diameters generally range from M3 to M30, and there are different lengths to choose from to meet various assembly requirements. For example, in small electronic products, smaller bolts such as M3 and M4 may be used, while in large mechanical equipment, bolts of M16, M20 or even larger specifications may be used.

Usually made of carbon steel, stainless steel and other materials. Blackened hexagon socket bolts made of carbon steel have low cost and average strength, and are suitable for some ordinary mechanical structures or equipment that do not require particularly high strength; blackened hexagon socket bolts made of stainless steel, such as SUS201, SUS304, SUS316, etc., have good corrosion resistance and can be used in humid and corrosive environments. They can effectively prevent rust and corrosion and extend service life.

Application of Blackened hexagon socket bolts

Because its appearance after blackening is relatively low-key and simple, and it has certain rust prevention and wear resistance, it is widely used in many industries such as machinery manufacturing, automobile manufacturing, electronic equipment, furniture manufacturing, and construction. In some occasions where the appearance is not high but practicality and economy are important, such as the connection of internal structural parts of mechanical equipment and the assembly of some ordinary furniture, blackened hexagon socket bolts (without knurling) can play an important fastening role.

Surface of Blackened hexagon socket bolts

Surface treatment

Blackening is one of its main surface treatment methods. A black oxide film is formed on the surface of the bolt by chemical or electrochemical methods. This oxide film can improve the surface hardness and wear resistance of the bolt, and to a certain extent enhance its rust resistance, so that it can maintain good performance under general environmental conditions. However, compared with surface treatment methods such as nickel plating and zinc plating, the rust prevention effect of blackening is relatively weak, and additional protective measures may be required in some harsh corrosive environments.