Omaha NAPE Engineer Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success!

The formation of a blister in boiler steel indicates the separation of layers within the material. Blisters are a type of defect that can be caused by factors such as overheating, improper welding techniques, or corrosion processes that lead to the formation of gas pockets within the steel. When these gas pockets accumulate, they can exert pressure against the layers of the steel, leading to delamination or separation. This can compromise the mechanical integrity and strength of the boiler, posing serious safety risks.

In the context of boiler operation, the presence of blisters can hinder the boiler's performance and reliability, and it often necessitates inspection and potentially significant repair or replacement. Understanding this defect is crucial for maintaining equipment and ensuring safe operating conditions.