Weld Failure Causing Multiple Fatigue Cracks in Pressure Vessel

Welding is a well-developed manufacturing process used for many decades since the Liberty Ships. However, weld failure occurs on a regular basis. Incorrect welding process or poor welding technique can be the source of many failures with fatigue as the major root cause. However, poor mechanical design can also be a major contributor to weld failure.

Many engineering structures use welding as a method of joining, this is especially the case for pressure vessel manufacture. This case paper covers all the areas of welding where due to numerous failures in welding process and selection, weld filler material and technique has caused exceptionally large numbers of welds to fail due to fatigue. Besides weld joining issues as a source, the material selection of the structural steels has also contributed considerably to the root cause of failure.

This paper will cover all the failure analysis details and techniques used in the analysis and the ultimate success in the improved design of the pressure vessel.