[updated:LAST EDITED ON Nov-24-04 AT 02:44 PM (CDT)]Hi, I have a question about some 4" coils we have in our facility. Most of these coils are SS TP316, and the water flowing through them has a chloride content of 40 mg/L. We have seen severe stress corrosion cracking, as well as possibly intergranular corrosion cracking. These coils are well on their way to failure due to thermal stress, physical stress, and possibly chloride content? We are going to replace them, but in the meantime it has been suggested that we do replacements with 316L coil sections. My question is, is this a waste of time? What good will it do to weld 316 and 316L together? Will you maintain any of the reasons to use 316L at a weldment by fusing it to regular 316SS? Also, how difficult is this weld? Will it be more difficult to weld 316 to 316L, and will we possibly end up with a bigger problem than if we just continue to use 316 coil material in the repairs? What electrode should be used in either case? In addition, I found out that the welders have been using 304SS chill rings for coil repairs, plus they have been using 316L welding rod to make 316 coil repairs. Any comments on these issues would be appreciated. Thanks in advance.....

Dave, on this issue, I was more concerned about the weldment. We are fixing our water quality issues so that 316 metallurgy should be OK (we are getting rid of the chlorides). Do you have any comments on welding a low carbon content metal to a standard carbon content stainless steel with regards to intergranular corrosion? Is it worth the money to spend on the 316L if we are just welding it to a 316SS coil that is existing?