The objective of this effort was to systematically explain the difference between predicted delta ferrite contents and the measured delta ferrite contents in the GTAW deposits made with ER 308L and ER 308L with precious metal additions, and to correlate findings with existing predictors of ferrite content. Deposit ferrite contents are critical to the hot cracking resistance of weldments. Furthermore, ferrite content plays a critical role in the corrosion resistance of weld deposits as well. In this investigation two stainless steel fillers were used to clad the inside diameter of a of stainless steel pipe. The filler materials differed only in precious metal additions. The cold wire GTAW process was employed, using a range of heat inputs. The samples were examined metallographically, and ferrite numbers were determined by magne-gage and by quantitative microscopy. Investigations have show that delta ferrite contents measured in GTAW weld deposits made with ER 308L + 1Pt filler material do not correlate well with accepted composition-based predictors of delta ferrite content. This is true over a wide range of heat inputs and process parameters. The study reconciles the effects of chemistry, solidification morphology, solid state transformations, magnetic properties, bead morphology, bead size and heat-input on deposit ferrite number.
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