Corrosion failures of industrial components are commonly associated with welding. The reasons are many and varied. For example, welding may reduce the resistance to corrosion and environmentally assisted cracking by altering composition and microstructure, modifying mechanical properties, introducing residual stress, and creating physical defects. This book details the many forms of weld corrosion and the methods used to minimize weld corrosion. Chapters on specific alloys groups--carbon and alloy steels, stainless steels, high-nickel alloys, and nonferrous alloys--describe both general welding characteristics and the metallurgical factors that influence corrosion behavior. Corrosion problems associated with dissimilar metal weldments are also examined. Case histories document corrosion problems unique to specific industries including oil and gas, chemical processing, pulp and paper, and electric power. Special challenges caused by high-temperature environments are discussed. Commonly used methods to monitor weld corrosion and test methods for evaluation of intergranular, pitting, crevice, stress-corrosion cracking, and other forms of corrosion are also reviewed.

The corrosion of welded joints is dependent on a number of factors such as corrosive media, temperature, method of exposure, contact with other substances, as well as the quality of the welded joint itself.

When considering the operational performance of stainless steel weldments the most important points to consider are corrosion resistance, weld metal mechanical properties and the integrity ofthe weldedjoint. Mechanical and corrosion resistance properties are greatly influenced by the metallurgical processes that occur during welding or during heat treatment of welded components. This book is aimed, there fore, at providing information on the metallurgical problems that may be encountered during stainless steel welding. In this way we aim to help overcome a certain degree of insecurity that is often encountered in welding shops engaged in the welding of stainless steels and is often the cause of welding problems which may in some instances lead to the premature failure of the welded component. The metallurgical processes that occur during the welding of stainless steel are of a highly intricate nature. The present book focuses in particular on the signif icance of constitution diagrams, on the processes occurring during the solidification of weld metal and on the recrystallization and precipitation phenomena which take place in the area of the welds. There are specific chapters covering the hot cracking resistance during welding and the practical welding of a number of different stainless steel grades. In addition, recommendations are given as to the most suitable procedures to be followed in order to obtain maximum corrosion resistance and mechanical properties from the weldments.

Hot corrosion of the weldment is the result of the reaction between oxidation and sulfidation, which affects welded joints exposed to combustion gases containing sulfate coal ash at high temperature. It is also demonstrated that welding processes, weld consumables, temperature of exposure, and mixture of salt environment are important factors in hot corrosion of the weldment.

Key articles from over 10 separate ASM publications are brought together as a practical reference on weld integrity crack prevention. This book thoroughly covers the essentials of weld solidification and cracking, weldability and material selection, process control and heat treatment, failure analysis, and fatigue and fracture mechanics weldments. Contents also include an appendix for quick reference of tabular data on weldability of alloys, process selection, recommended interpass and heat treatment temperatures, and qualification codes and standards.