How does a corroded pump influence at a railcar tank cleaning

Cast iron pumps are widely used in a department of railcar tank cleaning to pump hot water which is necessary in the cleaning process. As a result cast iron impeller shows considerable corrosion after operating due to the high temperature of the pumping water.
Materials and methods
Analysis of a substantial wearing of the cast iron impeller.
Results
Mathematical analysis have shown that substantial wear of the cast iron impeller causes head decreasing, moreover, it takes more time necessary for the railcar tank cleaning process.
Сonclusions
1. The analysis showed that corroded passes between adjacent vanes of the cast pump impeller is the main cause of increasing therailcar tank cleaning process to 15 percent.
2. The chance of the time increasing which is necessary for the railcar tank cleaning process is negligible in the absence of the corrosion process, but a corroded cast iron impeller could increase the time necessary for oil cargo transporting.