INTRODUCTION
This paper describes three case studies in the Gas & Refining Industry in which some corrosion and blockage problems were detected. In these cases the failures were a result of an inappropriate material selection during Engineering Design phase. A common factor was identified: failures occurred in a very short operating time. Economical, maintenance and even safety issues were consequences of the failures. The first case was a corrosion problem in the 316L (UNS S31603) filters installed in four fire-seawater pumps. They were located at the Jetty of an LNG Terminal and the failure occurred after two and a half years of operation. The second case documents a leak produced in a Spent Caustic Treatment Reactor Alloy 20 (UNS N08020) after nine months in service. The third case addresses blockage problems (after a few days of operation) in a sodium hypochlorite dosing pump. Crystals were generated when sodium hypochlorite got in contact with the Alloy 20 (UNS N08020) material. For each case the root failure causes and the new material proposal is described.
Failures in the industry due to poor material selection are not so uncommon. Sometimes they appear to be related to a lack of previous information (such as future operating conditions, material properties, detailed fluid composition). Others can be related to an incomplete understanding of the corrosion phenomena affecting the component. In other cases a lack of knowledge in material engineering subjects can be the cause. In some cases failures can even arise from a hasty material selection due to the present way of developing projects (reducing time and budgets to perform engineering works). Material selection is an important and complex engineering function in a project and full attention must be paid even during the early stages of design (Basic Engineering included).
