Aluminum die cast ladle repair

[Jerry]

I just did a job where I repaired some ladles. First I plasma cut out the bad area, ground and then patched with 11 g stl. st. Customer said ladles made of stl. st. (OOPS he didn't say anything about corrosive, maybe I should of known oh well)

Thus the problem I used 11 g 304 stl. st. and since found that aluminum is very corrosive in a molten state, and the patch I was told disintegrated immediately. I am thinking now that 316 stl. st. would of been the correct stl. st. for it is used for its corrosive properties right ?

I patched this by overlapping the patch and tig welding all around, but this way of patching creates a cut out area inside ladle, I now think material would build up here and cause problems ?

Or should a patch be placed inside the cutout where by it fills the cut out and where I would be doing a butt weld all around, therefor the inside would be smoother.

Thanks guys for any info J P Streets Welding

[Rocky D]

316L for low carbon is the correct SS to use, and when corrosives are involved, be sure there are no places for the corrosive to puddle or get trapped inside...butt joints may require a more difficult fit, but would eliminate trapping. A lap could possibly leak ti the inside if the lap and erode from the inside out, thus causing a failure that wouldn't be noticable from the outside, till it broke!
The first question to ask is, Why did the need repair in the first place? Then try to fix it in a way that will avoid that from happening again. On the other hand, that may not be good for business.
I hope I understood your question correctly, but if I didn't...I hope you found this interesting reading, anyway.

[Jerry]

Thanks rocky, I see were thinking the same on this, at least I am now. I didn't know aluminum was so corrosive or would of used 316 from get go. I think I'll be giving this a try again with 316 and butt welding in the patch.