Accumulator Erosion

[RyanMAN]

A 15 year old carbon steel industrial hot-water accumulator (4000 gallon capacity) that my company is consulting on, is suffering from premature erosion opposite a water inlet nozzle.

The plan is to build up the SA 516-70 carbon steel shell (1.25" thick) with a two-layer patch of austenitic stainless steel weld cladding

Layer one will be welded with 309L and layer two will be welded with 308L filler metal. The area of the patch will be approx. 9 sq. ft. The patch will be applied on a vertical wall.

Do you have any ideas for process options or procedures?

Thanks

Ryan

[4sfed]

The plan is to build up the SA 516-70 carbon steel shell (1.25" thick) with a two-layer patch of austenitic stainless steel weld cladding
Ryan

Using stainless for the patch will increase the rate of corrosion on the rest on the shell. The galvanic potential between carbon steel and austenitic stainless is not great, but there is a difference.

http://www.eaa1000.av.org/technicl/c...n/galvanic.htm

Since water is present, you certainly have an electrolyte, and higher temperatures only accelerate the corrosion process.

I would recommend matching the shell material and filler as closely as possible.

-jim

[MMW]

Add a baffle or diverter at the inlet so it will not point directly at the opposite wall.

As for the repair area I would patch or build up the area with the same material as the tank.

[RyanMAN]

thanks for you input, any suggestions for the process that should be used?
The welding has to be performed in side the tank and can only be accessed by a small hatch.

[Daniel]

Automatic welding machines. You can rent them. But I would suggest taking to your local Boiler makers union they will know exactely what to do. I've seen these machine put a coat of stainless on top of old stainless pipe, it's the perfect set-up.
But it doesn't come cheap at $250 000 a day.

[Donald Branscom]

How large is the tank?
I would start with an ultrasound test to see if the tank is worth repairing since it is 15 years old.

The ultrasound test can give you valuable info.
Or cut the patch out and do a visual inspection before deciding on the repair or repair procedure.

Also you did not say, but is the tank under pressure?