Vibration fatigue testing was conducted on socket welded joints of a design similar to that used in small bore pipe welds in nuclear power plants and on several potential design improvements. The objective of the testing was to better characterize and understand the high cycle fatigue resistance of such welds, and to develop remedial measures and standards for vibration-critical applications. The results indicate that the most promising design improvement consists of increasing the fillet weld leg length, along the pipe side of the weld, to twice the minimum dimension currently required by the ASME Boiler and Pressure Vessel Code (Section III, 19995 Edition), while maintaining the socket side leg at the Code minimum dimension. This configuration appears to offer about a factor of two improvement in high cycle fatigue strength reduction factor improvement in high cycle fatigue strength reduction factor over the standard Code value for socket welds, which is consistent with prior analytical results. Othe rremediation and design concepts tested yielded mixed results.
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