While doing non-destructive examination by LPI in a steam generator assembly (fillet welds of connecting strips to steam separator) a number of linear indications were observed in the weld. The materials of both the connecting strips and the steam separator were stainless steel with the weld made using ER 347 (Stainless Steel) wire. To ascertain the nature and the reasons for the incidence of the linear indications investigation was done using in-situ metallography on the welds.

2.0 NDE EXAMINATION:

Nondestructive Examination by PT showed linear indications in all joints initially and in about 26 joints after repair welding.

3.0 DELTA - FERRITE MEASUREMENTS:

Delta ferrite measurements were done on the fillet welds, test weld pad and the autogenous regions using ferritescope.

4.0 CHEMICAL ANALYSIS:

Chemical analyses were done on the fillet weld (removed from the actual job), connecting strip removed from the separator and weld deposit of ER 347 wire which was used in welding.