| Structural failures by fracture in oil and petroleum industries can have severe consequences both in term of loss of life and of economics. This severity will increase in the future as the size and complexity of installations increase. Industry must be constantly vigilant in learning from past failures and in studying the possible effects of changes in technology on fracture risks.; The combination of the effects of fabrication and operation, and of corrosive surroundings has not been clearly understood or analyzed. For structures in oil and petroleum industries, this complex interaction contributes to brittle fracture. In this research, the most common type of this combination is discussed and analyzed. The structure consists of a welded thick wall pressure vessel subject to primary loading and exposed to hydrogen at elevated temperature. To be more practical, a real case of a crack in a thick wall, welded pressure vessel under high hydrogen partial pressure and moderate temperature is selected from a petroleum refinery.; This research establishes a procedure to deal with the complex interaction of issues associated with material processing and corrosive atmosphere that are active in this process. It also establishes a formal procedure to predict the active life of a structure that has a crack and is exposed to a hydrogen-enriched atmosphere. To achieve that there are five major steps to be carried out in this work: (1) Welding process simulation. (2) Post Weld Heat Treatment (PWHT) simulation. (3) Material property degradation due to hydrogen embrittlement. (4) Stress analysis of the cracked specimen. (5) Fitness for purpose analysis. |
