Weld repair of ferritic welded materials for high temperature application

Weld repair of ferritic and austenitic materials, particularly related to high temperature applications, has become increasingly important as the life of high temperature operating plant has been extended to obtain the maximum economic benefit commensurate with rigorous safety requirements. This has led to the development of advanced and innovative repair procedures which rely on the improved understanding that now exists for the control of the microstructures developed in the heat affected zone and the weld metal. This review focuses on the weld repair of ferritic steels and considers the factors that contribute to the damage build up in components requiring repair, especially weldments, and the typical repairs that are required. It considers the basic features of conventional welds and weld repairs, the assessment of their performance, the principles of microstructural control and their application to advanced repair procedures. Finally, it examines the different methods of assessing the performance, the various controlling parameters, summarises the current guidelines and finally considers the future requirements. Wherever possible, use is made of reviews in associated fields.