Thanks for the replies so far everyone.
I don't think it's a problem with all ductile iron casings. I think it might be a problem specifically with this one pump. The metallurgist test is a good suggestion.
Agreed. But what is still puzzling is that the Cast Iron and other Ductile Iron pumps are not showing the same degree of corrosion.
Which leds us to suspect that it not only could be a combination of the sand/silt, but also a manufacturing/casting defect with this particular ductile iron pump?
Also wanted to mention that at the same location where the above ductile iron pump is used, we have a second pump that has a cast iron casing. The cast iron pump is not showing nearly as much corrosion as the ductile iron pump is.
There should not be much difference in corrosion advantage...
Thanks for all of the responses so far.
Yes, the pump is on intermittent mode and is not constantly used.
What are some of the causes of the erosion corrosion? Possibly the sand?
Artisi: You mentioned "fines" in the water? What do you mean by "fines"?
Yes, the impeller looks fine, so I am not suspecting cavitation, atleast on that portion.
As for the PH, when we are using the pumps for treated water, the PH can get as high as 8.8 to 9.
It's been reported that there is sometimes sand in the water. Could sand or silt have caused this damage?
The casings on two of our pumps are suffering from damage.
These two pumps are horiztonal split case, double suction with end discharge. They were manufactured by Worthington-Dresser in Germany in 1991. They are about 1000 HP, with Ductile Iron casings and bronze impellers.
The pumps are...
