Experience in in-situ repair welding of steam turbine shrouds and blades

Abstract

Cracking have been observed in the turbine shrouds and blades during routine maintenance shut down of power plants owned and operated by Nuclear Power Corporation of India Ltd. In-situ repair of these cracks were carried out using a welding procedure developed indigenously that employed gas tungsten arc welding process and austenitic stainless steel filler wire. Localised post weld heat treatment (PWHT) of the repair welds were also carried out. The turbine components thus repaired have been performing satisfactorily in service for more than three years. This paper presents the development of this welding procedure, its successful execution in the plant and performance of the repair weld in service.