Rusty welds???

[Westerngeophysical772]

3 years ago, I spent £500 on an exhaust for my Berlingo, Its an aluminised mild steel system .....3 years later its dropping to bits, I've removed the whole exhaust to investigate, and I have found that although the pipe work and cat and boxes are fine, all the welds show signs of severe corrosion and at 3 of the welds the aluminised pipe has perforated through where the weld joins the pipe. to me it looks like the system was aluminised in its seperate bits, then , welded together destroying the aluminised treatment and causing the corrosion at that point.. would you agree or disagree with that assessment?. cheers

 

[oilcooled :)]

i agree, if it a spurios exhaust pure gutter is all they are, be better of with kitchen roll exhaust oem far better

 

[TechnicAl]

It sounds like thats the reason. There could be another though. I think the aluminising process doesnt work as well on welds as it does on the sheet steel. The welds have more Silicon which sort of repels the Aluminium / Silicon alloy that they dip it with.
Im not 100% sure and I cant find any reference.

 

[aametalmaster]

I have been welding alumized steel for more than 25 years as a sheetmetal worker. The weld will always fail after time because its just mild steel. 99% of the guys after welding don't clean the welded area and spray some coating where the weld was so it will never last. I have seen lots of jobs over the years where either the paint was wore off and the alumized steel is still good but the welds have gotten rusty. I made my garage roof caps from 16 ga alum steel 23 years ago and painted the weld area one time when they were installed and they are showing rust now but there isn't any road salt on top of my garage to help eat the metal. Alumized steel is no different then galvanised steel it will be fine where there is no weld and always rust on a welded seam...Bob