Cavitation resistant fluid impellers and method for making same
AssigneeIngersoll-Dresser Pump Company
InventorsColin McCaul, Vincenzo Fumagalli
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Abstract
A fluid impeller for us in applications requiring superior cavitation erosion resistance. The impeller has a body fabricated from a castable metastable austenitic steel alloy which has a preferred chemical composition in the range of 17.5-18.5% chromium, 0.5-0.75% nickel, 0.45-55% silicon, 0.2-0.25% nitrogen, 15.5-16.0% manganese and 0.1%-0.12% carbon. Quantitative testing has shown cavitation resistance of four to six times that of standard boiler feed pump materials. A method for making cavitation resistant fluid impellers is also disclosed.
Claims14
A fluid impeller for use in applications requiring a high degree of cavitation erosion resistance, said impeller comprising:
- a body cast from a castable metastable austenitic steel alloy, said alloy having a chemical composition in the following range:
- ______________________________________ C Mn N Si Ni Cr ______________________________________ % min 0.08 14.0 0.3 17.0 % max 0.12 16.0 0.45 1.0 1.0 18.5 ______________________________________
- the balance comprising iron and impurities.
A fluid impeller for use in applications requiring a high degree of cavitation erosion resistance, said impeller comprising:
- a body fabricated from a castable metastable austenitic steel alloy, said alloy having a chemical composition in the following range:
- ______________________________________ C Mn N Si Ni Cr ______________________________________ % min 0.08 15.0 0.10 0.4 17.0 % max 0.12 16.0 0.30 0.8 1.0 18.5 ______________________________________
- the balance comprising iron and impurities.
A fluid impeller for use in applications requiring a high degree of cavitation erosion resistance, said impeller comprising:
- a body fabricated from a castable metastable austenitic steel alloy, said alloy having a chemical composition in the following range:
- ______________________________________ C Mn N Si Ni Cr ______________________________________ % min 0.10 15.5 0.20 0.45 0.5 17.5 % max 0.12 16.0 0.25 0.55 0.75 18.5 ______________________________________
- the balance comprising iron and impurities.
A method for making a fluid impeller having a high degree of cavitation resistance, comprising the following steps:
- selecting a castable metastable austenitic steel alloy from alloys having the following range of chemical compositions:
- ______________________________________ C Mn N Si Ni Cr ______________________________________ % min 0.08 14.0 0.3 17.0 % max 0.12 16.0 0.45 1.0 1.0 18.5 ______________________________________
- the balance comprising iron and impurities;
- fabricating said fluid impeller from said castable metastable austenitic steel alloy;
- and
- heat treating said fluid impeller by solution treating at 1050.degree. C. to 1100.degree. C. for one hour per inch of thickness followed by a water quench.
Dependencies are inferred from the claim text.