Our experience in the quality assurance in heat treatment of reactor components

Requirements to be met for quality assurance for heat treatment and post-weld heat treatment for stress relieving of reactor components are mentioned. Some case histories in which wrong use of heat treatment equipment led to rejection of components are described. For quality assurance, extensive tests and rigorous inspection must be carried on heat treated witness samples to detect internal defects such as overheating, burning, undesirable precipitates etc. Factors to be considered for selecting a heat treatment furnace are mentioned and the principal steps of the furnace calibration are discussed. Preproduction trials are carried out to assess the suitability of the furnace and heat treatment procedures with respect to the specified requirements. (M.G.B.)