We are investigating the root cause for a leak on our building spray piping. We have four leak indications, linear in nature running circumferential around the pipe. The leaks range in size from 0.2 to 1.1 inch in length. Penetrant Dye and Ultrasonic Testing indicates that the cracks are outside diameter initiated. The pipe is SA-358, seam welded 10 inch pipe that holds a 2500 to 3000 ppm boric acid solution for the building spray header (this portion of the piping is typically wetted). We found evidence of past deposits of duct tape adhesive on the pipe exterior at the leak location and we are sending scrapings off for analysis. We've also sent the pipe section off for analysis. The leak locations are all within three inches of each other and form a pattern ten inches away from an end weld and at least four inches away from the seam weld. We're down to 1) SSC induced by the chloride content of the tape adhesive (adhesive deposit is probably 20 years old or older) but there is no mechanical stress in this area of the pipe, or 2) manufacturing defect, or 3) a combination of both. I understand SA-378 to be formed from SA-240 sheets and seam welded and annealed. The pipe is then straightened and pickled. Assuming that the pipe straightening operation is a cold working process could the straightening operation have induced the residual stresses that the adhesive chloride was able to attack? Any thoughts from anyone?