CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 2
C H A P T E R 2
Corrosion Issues of Austenitic Stainless Steel in Nitric Acid
Material, Medium & Mechanism
The chapter gives brief introduction to the austenitic stainless steel with respect to their
formation using Fe-C, Fe-Cr, Fe-Cr-Ni phase diagram, microstructure, physical, mechanical, and
chemical properties. Apart from this, the chapter introduces to the process environment of nuclear
fuel reprocessing, and the various corrosion problems of austenitic steel in the oxidizing
environment of nitric acid.
2. 1 Introduction
Economy in the production and construction of industrial plant, and equipment depends
upon the existence of good processing properties as well as the cost of the materials to be used.
The satisfactorily performance of the materials depends upon many features, such as selection of
proper material, appropriate design, fabricability, sustainable mechanical and physical properties
of the designed structure/equipment, chemical conditions of the process environment, and their
maintenance aspect. However, the interplay between these chemical, mechanical and physical
properties produces a wide range of requirements which must be considered in choosing the
correct material for the application in question. The most important material properties required
are mechanical strength and ductility, machinability, sufficient cold and hot formability, excellent
weldability, and good corrosion resistance. Austenitic stainless steels [33] are widely used as
constructional materials in various industries such as nuclear and other chemical processing
industries, food processing industry, hydro-power generation, and for many other engineering
applications. The advantages with this class of materials are (a) exceptional formability, (b)
resistance to brittle cleavage at low temperature, and good mechanical strength at higher