Heat treatment effect on radiation stability of electroslag welded joint of Mn-Ci-Cr-Mo type Czechoslovak steel

The effect was studied of heat treatment on radiation stability of base material and of the transitional zone of an electroslag welded joint of Mn-Ni-Cr-Mo steel for a reactor pressure vessel. The shift in transition temperature between irradiated and nonirradiated state and the upper level values of notch impact strength were chosen as criteria for assessment. Specimens were irradiated with fast neutrons with a fluence of 2.3 to 2.7 x 1023 n/m2 at a temperature of 100 degC. Prior to irradiation, the welded steel specimens were treated with five different methods. Primarily studied in the specimens was the course of notch impact strength in dependence on temperature. It was found that any processing of material resulting from welding and heat treatment affected the radiation stability of the material. (Z.M.)