Failure of Large Engine Pivot Bolts

Like most failure investigations this one started with a phone call. In this case the bolt was a special part, a ¼-28 2A X 18.5 socket head screw with spherical radius head geometry and an induction hardening callout on the head. The bolts were used on large diesel engines and were experiencing cracking at the base of the socket during installation. This presentation goes through the steps of our investigation as we identified the root causes of the fractures and our corrective action.