High-Quality Galvanized Hex Socket Bolt
Basic Parameters and Materials
Specifications and Standards: Common thread sizes cover M2-M24, with lengths ranging from 5mm to 100mm. Longer sizes can also be customized upon request. They conform to the GB/T70 series standards. Galvanized hex socket head cap screws with flat round heads follow GB/T70.2-2000. Some export products may conform to the German standard DIN912.
Common Materials: The base material is mostly carbon steel or alloy steel, suitable for different strength grades such as 4.8, 8.8, and 12.9. For example, high-strength 12.9 grade bolts often use high-quality alloy steel, and undergo hydrogen removal treatment before galvanizing to prevent breakage during use. For special corrosion-resistant applications, 304 or 316 stainless steel base materials are also used for galvanizing to further enhance corrosion resistance.
Usage Precautions: Use a matching hex wrench during installation to avoid slipping and damaging the hexagonal grooves on the bolt head. Control the torque carefully to prevent overtightening, which could damage the threads, or undertightening, which could affect the tightening effect.
For high-strength hexagonal bolts of grade 8.8 and above, cold galvanizing is preferred to avoid the high temperature of hot-dip galvanizing affecting their strength. These high-strength bolts require pretreatment such as pickling and secondary cleaning before cold galvanizing to ensure coating adhesion.
When connecting different metal parts, insulation measures must be taken to prevent electrochemical corrosion caused by damage to the galvanized layer, which would shorten the bolt's service life.
