Salt corrosion of welded 316L & 430
Salt corrosion of welded 316L & 430
(OP)
I have a multi-component assembly of deep drawn and machined stainless steel parts that are YAG laser welded & finally partially over molded with nylon 612. I'm getting red rust staining from 2 of the welds that are encapsulated in the nylon over mold after 96 hours of salt spray. One of the welds is deep drawn 316L to 316L, the other is deep drawn 316L to deep drawn 430 with the carbon and manganese restricted.
There are 3 other welds between deep drawn 316L to machined 440C, stamped 304L to machined 440C and deep drawn 430 to machined 430F that don't rust. All of these 3 welds are outside the nylon over mold. All 5 welds are produced with the same YAG laser but with different weld schedules.
I expected more trouble from the 440C welds, not the 316L. Could it be caused by the nylon over molding?
I found this link but it doesn't really cover my problem:
http://www .eng-tips. com/viewth read.cfm?q id=252253& amp;page=1
There are 3 other welds between deep drawn 316L to machined 440C, stamped 304L to machined 440C and deep drawn 430 to machined 430F that don't rust. All of these 3 welds are outside the nylon over mold. All 5 welds are produced with the same YAG laser but with different weld schedules.
I expected more trouble from the 440C welds, not the 316L. Could it be caused by the nylon over molding?
I found this link but it doesn't really cover my problem:
http://www





RE: Salt corrosion of welded 316L & 430
RE: Salt corrosion of welded 316L & 430
RE: Salt corrosion of welded 316L & 430
This is a head scratcher. Maybe the coating is porous and allows salt to concentrate underneath it? Maybe the nylon is absorbing salt water (usually a problem with nylon 6 and 6,6 but usually not with 6,12)? Maybe there is a corrosive component in the coating (plasticizer, heat stabilizer, etc.).
RE: Salt corrosion of welded 316L & 430
RE: Salt corrosion of welded 316L & 430
RE: Salt corrosion of welded 316L & 430
I would look at possible corrosive components within the nylon. Of course, full pickling and passivation is excellent advice and best practice.