What is a unique inspection task for twist-off type tension control bolt pretensioning?

In the context of twist-off type tension control bolt pretensioning, checking for severed splined bolt ends is a unique and critical inspection task. Twist-off tension control bolts are designed to ensure a precise level of tension by using a wrench to turn the bolt head until a predetermined torque is reached. During this process, the splined end of the bolt shears off once the correct tension is achieved, providing a visual indicator that the installation was completed correctly.

Severed splined bolt ends signify that the bolts were adequately tightened to the necessary pretension level and that the installation meets engineering specifications. This distinguishes the task from other general inspections such as checking for rust on bolt threads or confirming washer integrity, which might not be unique to this type of bolting system. Additionally, while verifying the calibration of the wrench is essential to ensure accurate torque application, it is not a unique inspection task specific to twist-off tension control bolts, as proper tool calibration is required across various bolting methods. Hence, checking for severed splined bolt ends is specific to the process and contributes significantly to confirming the integrity of the connection.