Characterization of Confined Pinch Welds in Type 304L Stainless Steel

Efforts have been undertaken to characterize the stresses induced in resistance pinch welds used to seal vessels which contain high pressure radioactive gasses. Subsequent to the weld a costly and time consuming process, known as hot air decontamination (HAD) is used to remove the radioactive gasses that are entrained in the weld and surrounding metal. A process to replace HAD is under development. To qualify this new process it must be shown that the mechanical and physical properties of the weld are substantially the same as those using HAD.. These properties include the weld microstructure and the residual stresses in the vicinity of the weld. The method of making pinch welds is first described as well as one cutting method. The methods of characterizing the weld and a comparison between cut and uncut specimens by several characterization methods are presented.