A325 HDG High Tensile Hex Bolt (Millimeter)HDG stands for “hot dipped galvanized” and pertains to bolts coated with a thin layer of zinc to protect them from corrosion and rust. HDG bolts are often made of metal, such as steel, that has been immersed in a molten zinc bath till even the insides become galvanized. The result is a metallurgical bond between the zinc coating and the steel substrate. These bolts are often used in areas where corrosion is a concern, such as outdoor structures, coastal areas, and other corrosive environments.

A325 HDG High Tensile Hex Bolt

SKU: 0038

Color

High Tensile bolts are made from carbon and/or alloy steel. These bolts are quenched and tempered to reach the required tensile strength. They are considered structural-grade bolts and are used in high-strength and load-bearing installations, such as automotive, construction, and machine industries. Under the metric grade of the ISO (International Standard Organization), the bolts are classed from 4.6 to 12.9, where the hardness, ductility, wear, heat resistance, and tensile strength of the bolt rise with the numerical value. The class of the bolt is punched into the head of the bolt and is a visible indication of a metric bolt. The six sides of the hex head allow a firm grip during tightening or loosening. This bolt is used with a torque wrench/gun to reach the proper preload of the bolt. Commonly with a zinc (galvanized) or plain (oiled) finish, these bolts can come with a shank and thread or with a full-threaded grip length. The bolt's diameter, length, and class depend on the manufacturer’s specifications.