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How calculate corrosion allowance of HYDRAULIC TURBINE

How calculate corrosion allowance of HYDRAULIC TURBINE

(OP)
How calculate corrosion allowance of HYDRAULIC TURBINE.

The information I have
1. Material is EN-JS1030 (QT400-15)Spheroidal graphite cast iron
2. Fluid is water (Chloride=220 ppm)



Thank You

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

hi
it looks it is painted inside too, can you confirm?
bye

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

Could you provide some additional information regarding the water? A good start would be water type. (River water, cooling water, steam condensate, sour water etc.) Type will dictate further questions but try and provide background information regarding the variables that affect corrosion in your system (presence of oxygen, velocity, pH, inhibitor, temperatures, chemical treatment, etc.)

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

hi
even knowing pH, oxygen, water origin, etc., you will have difficulties in calculating any corrosion rate and also in concluding that cast iron is OK for the service in absence of coating...
In my opinion, only the coating provides the resistance, I would go for usual 3mm corrosion allowance in addition to the existant coating material, but whatever corrosion allowance is, it will probably not sustain the conditions without the coating.
once the coating is off, you may probably experience severe corrosion of the cast iron by water with unknown characteristics.

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

(OP)
Thank you all To educate. I have the information of water. Hope you can help me.


RE: How calculate corrosion allowance of HYDRAULIC TURBINE

(OP)
Chumpes ..... Inside no painted.

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

The parameters seem quite okay. Deposition (mainly silica) seems to be more of a problem than corrosion. The corrosion and scale inhibitors should work fine. You may add some biocide in the system.

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

i cannot find oxygen content in your information

RE: How calculate corrosion allowance of HYDRAULIC TURBINE

With hydro turbines it is really hard to predict wear rates, especially in high head situations (is this a pelton wheel?)
Sand is your worst enemy; chlorides not necessarily so much if temperatures are low. But it's a function of the overall fluid makeup and operating conditions. Wear in hydro turbines (and pumps) will be highly localized, so a stock corrosion allowance is not really a useful approach.
Run it and see is the best answer I can give; predicting is a mug's game. Past performance in the same environment (if there is any data) is your best guide.
Personally I would not use cast iron for anything at all critical (and I've built a fair few hydro turbines). I also learned from designers that cavitation (the classic wear mode in turbines) is best combatted by design rather than by barriers. Obviously abrasive environments are another matter altogether. Coatings won't buy you any wear protection.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

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