Is substituting P91 for P22 justified?

Abstract

While refurbishing fossil fuel power plants, it is of great importance for safety precaution to replace the aged components which exceeded their designed service life with new ones. The most important parameter for thick-walled components is thickness value and the most important procedure is its reduction. Reduction of wall-thickness is achieved by changing the material of thick-walled components. In present paper some examples of wall-thickness reduction are shown in case of substituting a ferritic/martensitic micro-alloyed steel P91 for P22.