Effect of composition on ductility dip cracking of 690 nickel alloy during multipass welding. (September 2020) - Rapetti, A.
Abstract: This paper deals with Ductility Dip Cracking (DDC) during multipass welding of 690 filler metals. In addition to industrial alloys (152 and 52 M), model alloys of controlled purity were also used to unambiguously demonstrate the effect of elemental sulphur and carbon. The sensitivity of each alloy to DDC was measured with the recently developed Refusion Cracking Test (RCT). It is confirmed that the cracks observed in this study result from DDC, not from liquation nor solidification cracking. DDC cracks are in most cases observed after several welding passes. The detrimental effect of sulphur and beneficial effect of carbon on the resistance to DDC are clearly evidenced. The good resistance to DDC of the industrial alloys, compared to the model alloys, is related to their niobium content.