As a metallurgist I would say that extensive testing is in order. Doesn't have to take long. But this is a very serious situation. Imagine building a ship with steel that as altered mil test. Or even worst the steel could contain smal % of poisonous element (An element that greatly affect the physical property of the steel) that can make the steel brittle at lower temperature.
Anyway I'm sure you guy's in the Navay are on top of thing, Right?