4. Corrosion Anchor bolts, particularly those made from carbon steel, are vulnerable to corrosion when exposed to moisture and other corrosive agents. Corrosion can weaken the bolts and their connection to the structure, increasing the likelihood of loosening.

Black hex head bolts are commonly made from steel, often alloyed with other elements to improve strength and durability. The most common grades used in manufacturing these bolts are Grade 8 and ASTM A325, which are known for their high tensile strength. In addition to steel, these bolts may also be made from stainless steel or other materials that offer specific mechanical properties suited for particular applications.