welding of generator exhaust elbow 1

[tonylazyz]

I am currently involved in a new ship construction. The vessel has three Kohler generators powered by John Deere (marinised) diesel engines. The diesel exhaust is cooled by sea water injected into the exhaust elbow just after the turbo. The shipyard has had to move the sea water injection point and in doing so has made welded repairs to the manufacturer's elbow. From previous experience with water cooled exhaust elbows I suspect these welds are substandard and will not last long. Does anyone have any suggestions about welded repairs on mild steel, water-cooled exhaust elbows? I know this depends on the type of material originally used. Are there any heat treating or surface treatments that would benefit this situation?
Thanks
Tony

 

[MikeHalloran]

Mild steel exhaust elbows? Are you kidding? No matter; whoever made the elbows is not going to honor their warranty if you so much as touch them with a welder or a grinder.

Go to a marine exhaust specialist and get custom wet elbows made with the exact inlet configuration you desire. Pay the premium and get the duplex stainless.

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A former employer of mine, DeAngelo Marine Exhaust of Fort Lauderdale, enjoys a good reputation and makes OEM elbows for Deere, Cummins and other engine manufacturers.
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Mike Halloran
Pembroke Pines, FL, USA

 

[tonylazyz]

Thanks Mike - I have used DeAngelo in the past and will do so again. The only problem is this project is in Italy. What spec SS would you recommend for exhaust elbows?
Thanks
Tony Schultz

 

[MikeHalloran]

DeAngelo will give you a one year warranty on a 316L part.

Their warranty for duplex, which they call 'S-M-O', is three years or five years, depending on whether the parts self- drain when the engine is idle.

They do business with boatbuilders and repair shops and individuals all over the world. Location is not an issue. Fax a drawing, or send what remains of the part you want to replace, or build a mockup from PVC sewer pipe, or wood or whatever.



Mike Halloran
Pembroke Pines, FL, USA

 

[EdStainless]

There are a number of these guys around the country, NJ, WI, CA. Just make sure that they have a track record with the engine companies and offer warranty. In general, if they offer various options they probably understand.

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Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[MikeHalloran]

As Ed says, a history and a warranty provide some assurance.

Anybody with a TIG welder and a plasma cutter can enter the marine exhaust business, and a lot of anybodys do. Most of them produce beautiful welds. Some can produce tubing in arbitrary sizes and exotic materials to meet their needs. Some produce their own short radius elbows. There is zero demand for normal or long radius elbows in the trade, because boatbuilders never leave room for them.

So far as I know, there are no engineers in the business anywhere, so asking a technical question will trigger a barrage of bafflegab and/or amazing pseudoscience and/or, uh, used forage.

A guy who's been at it a while will have some idea of what feaatures work, and will keep copying until he gets it right.



Mike Halloran
Pembroke Pines, FL, USA