What might bulged metallic linings result from in a pressure vessel?

Bulged metallic linings in a pressure vessel are primarily caused by issues related to thermal expansion or a failure in the integrity of the lining itself, such as a leak. When the temperature within the pressure vessel increases, the materials, including the metallic linings, expand. If the expansion is restricted or if there is a malfunction in the lining—such as a leak that leads to pressure build-up or fluid accumulation—the metallic lining can bulge. This situation typically indicates that there has been an inability of the lining to accommodate thermal changes or that it is compromised, potentially leading to further damage or failure if not addressed.

Inflated insulation material could create pressure but would not directly lead to bulging of the metallic lining. Improper pressure regulation may maintain a pressure level that is either too high or too low, but it would not specifically cause the lining to bulge without additional contributing factors like thermal effects. Excessive paint application may lead to surface issues but is unlikely to be a direct cause of bulging in the context of the structural integrity of the metallic lining itself.