Modeling and establishment of database for the prediction of the welding characteristics in pressure vessel steel welds

Welding action in general causes to form heat cycle affected area which is different in its physical and mechanical properties from the original material. Especially when it happens during the welding on reactor pressure boundary material it will give a serious problem in safety. Understanding the fact that the material property changes by welding have something directly to do with micro-structure of the material, US, France and few other advanced countries, therefore, have been studying on the changes of micro-structure by heat cycle and the prediction of mechanical property changes since 1970s. The results of those studies eventually led to the establishment of the theory of phase transformation. This report describes domestic effort of prediction reference modeling through integration of data from diversified characteristics of weld affected areas of reactor pressure boundary materials. This report also introduces the status of related technology development from Japan, france, US including that of Korea. (Hong, J. S.)