Correlation between Microstructure and J-R Fracture Resistance of AISI Type 347 Weld

The influence of the microstructure on the J-R ductile crack growth resistance of austenitic stainless steel AISI Type 347 welds was examined. The optical and electron microscopy, and chemical examinations and XRD analysis were conducted on a series of J-R test specimens which were tested at 316oC. It was concluded that the J-R property of the Type 347 weld decreased with increasing the contents of the Nb(C, N) precipitates which were dependant on the carbon contents of the filler metals. The higher δ-ferrite content also deteriorated the J-R property of the Type 347 weld.