A power plant engineer has many choices when selecting tubing materials for hiscondenser, feedwater heater or balance-of-plant application. The wide variety ofstainless steel choices available (ASTM lists over 75 alloys) gives the engineer greaterflexibility to choose the best candidate to meet budgetary constraints and still providethe performance needed for the lifetime of the plant. Unfortunately, upset conditions arecommon in power generation, and these can result in premature unexpected failure oftubing and piping materials. These may include differences in operation modes fromdesign, changes in water chemistry due to leaks in other parts of the system, corrosionfrom unexpected sources, impact of improper lay-up practices, and the effect ofcorrosion product transport to other parts of the system. The motivation to build moderncombined-cycle and coal power plants for the lowest cost per kilowatt has stretched theenvelope for materials performance resulting in many tube failures.This paper provides an overview on a number of factors known to cause failure of atube material. Knowing the limitations of material is crucial when making a selection fora specific application. This paper helps to identify the factors that need to beconsidered when selecting a material. Properties compared in this paper includecorrosion resistance, stress corrosion cracking potential, thermal and mechanicalproperties, erosion resistance, vibration potential, and temperature limitations. Theproperty comparison guides are intended to be quick tools to assist the user in selectinga cost-effective material for a specific application.
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