Which bolts shall not be reused according to specifications?

The rationale for identifying A490 and galvanized A325 bolts as not suitable for reuse aligns with their specific material properties and application requirements. A490 bolts, which are high-strength bolts, require precise tension and load-bearing capabilities created during the initial installation. Reusing these bolts can lead to compromised structural integrity, as they may have already experienced loading cycles that could weaken their tensile strength.

Galvanized A325 bolts are also discouraged from reuse due to their coating process, which may influence the threads and overall performance of the bolt upon reuse. The galvanization can create surface irregularities, and once the bolts are reused, the integrity of the coating is also at risk, potentially leading to corrosion and loss of mechanical properties.

On the other hand, the other types of bolts in the question, such as A325, A307, and A192, do not have the same level of restrictions against reuse. While care should be taken when reusing any type of bolt, these particular bolts have specifications and applications that allow for their reuse under proper conditions, provided they are checked for wear or damage. Thus, emphasizing the importance of adhering to the guidelines around the reuse of A490 and galvanized A325 bolts ensures that the structural connections maintain their intended reliability and safety standards