Heat input plays an important role in mechanical, metallurgical and other properties like corrosion resistance of weld in the fabrication industry. Although there are so many problems associated with the welding of austenitic stainless steel but inter granular corrosion is most critical one of them. 21% Chromium 13% Nickel Stainless Steel is used for various applications at elevated temperatures above 700o C such as the catalytic convertors, nuclear industry and automotive exhaust systems and in pulverized coal burner nozzles of coal fired thermal plants due to supposition that it is corrosion resistant. But due to the high heat input during welding, sensitization or inter granular corrosion occurs in the Heat affected zone (HAZ). This book is very fruitful for the students, academicians & researchers working in this area.