Welding White Cast Iron in Sulphuric Acid Service
Welding White Cast Iron in Sulphuric Acid Service
(OP)
We have a submerged pump casing with a minor pin hole through a web section. The casing is submerged and in hot sulphuric acid service.
I have spoken with the manufacturer who is not keen to advise on the material propoerties other than it is made of a white cast iron. They have also advised that the material is "unweldable" which I find hard to believe.
As the pump casing is only four years old and the defect appears to be from a localised alloying concentration, as the remaining pump casing seems fine, I am keen to try a localised weld repair. Does anybody have any advise on suitable weld methods, consumables and welding parameter control etc.
I have spoken with the manufacturer who is not keen to advise on the material propoerties other than it is made of a white cast iron. They have also advised that the material is "unweldable" which I find hard to believe.
As the pump casing is only four years old and the defect appears to be from a localised alloying concentration, as the remaining pump casing seems fine, I am keen to try a localised weld repair. Does anybody have any advise on suitable weld methods, consumables and welding parameter control etc.





RE: Welding White Cast Iron in Sulphuric Acid Service
This alloy is termed nonweldable. However, if you insist on trying to fill up this pinhole defect,you may try a high Ni welding rod. This will fill the pinhole but the properties will differ as you are filling with a soft material. There will be no fear of cracking etc.Alternately putties are available with different grades of filler metals which you can try. Hope this helps.
RE: Welding White Cast Iron in Sulphuric Acid Service
Drill and tap the hole to 1/8" pipe thread.
Install a threaded plug.
If temperature is too high then plastic is not suitable as a plug. I am not sure what alloy plug would be suitable, but 1/8" pipe plugs can be obtained in many alloys and one could easily be custom made from the correct alloy, even the identical white iron alloy.
PUMPDESIGNER
RE: Welding White Cast Iron in Sulphuric Acid Service
Does the pump manufacturer use or have 1/8" plugs or perhaps 1/4" plugs available in that identical alloy that perhaps they use in their manufacturing?
PUMPDESIGNER
RE: Welding White Cast Iron in Sulphuric Acid Service
RE: Welding White Cast Iron in Sulphuric Acid Service
RE: Welding White Cast Iron in Sulphuric Acid Service