Many pressurized water reactor (PWR) plants have used weld overlays to mitigate the pressurizer dissimilar metal welds that are susceptible to primary water stress corrosion cracking (PWSCC). These configurations typically consist of SA-508 Class 2 low alloy steel welded to a stainless steel safe end by Alloy 82/182 weld metal. The overlay weld metal is typically Alloy 52M. In a few cases, solidification cracking (hot cracking) has been observed on the stainless steel portion of the configuration when the first weld overlay layer is deposited. To overcome this problem, a process consisting of deposition of ER308L or ER309L stainless steel buffer layer for the first layer in conjunction with a low Power Ratio welding procedure has been developed and applied successfully. The Alloy 52M weld overlay is then deposited after the buffer layer. This paper discusses the causes of the hot cracking and test programs to develop the parameters for the welding of the buffer layer and subsequent weld overlay layers. In addition the results of analysis performed to determine the impact of the buffer layer on the post weld overlay residual stresses are also discussed.
The General Klectric Company iK engaged in a major program of dovelopin;',, dcsi};ni"S anc ' ni.TniifacLnri.ng a larf;e riiiporconfluct". inft magnet in support of the Large Coil Program, which if; f mid oil by the U.S. Department of Energy aru! directed by the Oak Ridge Nation^] Laboratory. The: oval: ;!i:iped toroidal, in.ignei; vcighs approximately 'VJ7'kH, with hrirc d iamr-.tor;; of 3.35m and 2.35m; and is designed for a maximum magnetic field of 8T at: 30.65 kA. Limi tat ion:; on naf.net weight and available apace for .structural component;; coupled with extremely large magnetic force.. 1 , presented a major challenge in the selection of a mutable structural material. Detailed considerations of de;;ign and fabrication requirements of the coil resulted in the selection of Type 3161,M stainless stc^ol for major structural components. In support of the magnet development effort, an extensive test program was initiated to verify expected base metal properties, to develop weld processes and to establish weld and base metal design allowables. This paper presents the results of the test program which involved testing and evaluation of 25mm thick Type 316LN plate, shielded metal arc weld (SMAK) deposits selected for structural welds, gas tungsten arc t>/e.ld (GTAU) and gas metal arc weld (GMAW) deposits selected for seal welds. The welding development eEfort including measurements of impact properties at RT and 77K; chemical analyses; measurements of magnetic permeabilities and weld ferrite contents, metallographic and radiographic examinations of welds were performed at the Materials and
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