This comprehensive book addresses to the serious problem of erosion in various engineering applications and presents the investigation study of nitronic steel as the alternate material for 13/4 martensitic stainless steel for underwater parts of hydro turbine. It is structured in eight chapters which deal with the brief introduction of erosion phenomenon, review of all the aspects of the problem and the remedial measures followed by the strategy for the design of erosion resistant material, preliminary experimentation, experimental procedure and techniques and then the critical analysis of the results of all the tests performed on two grades of nitronic steels and finally the summary of the important outcomes of the study which underlines the potential of 23-8-N nitronic steel as a new erosion resistant material. This book will be beneficial to the students of Mechanical and Material Engineering. It will be extensively useful to the post graduate students and research scholars in this field.