In Situ Francis Turbine Blade Replacement due to Gross Cavitation
In Situ Francis Turbine Blade Replacement due to Gross Cavitation
In Situ Francis Turbine Blade Replacement due to Gross Cavitation
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Technical Aspects of Repair<br />
• Material and type dependent, castings are readily weldable<br />
• Casting structures of this era (1900-1920) are particularly<br />
prone <strong>to</strong> variable chemistry and are very porous<br />
• Water immersion of the components allows moisture <strong>to</strong> migrate<br />
throughout the casting filling those voids and pores<br />
• Moisture in the substrate not conducive <strong>to</strong> high quality defect<br />
free welding product<br />
• Trapped water pockets will flash <strong>to</strong> steam at exposure <strong>to</strong> the<br />
extreme temperatures of fusion welding<br />
• Gases become entrapped in the weld metal<br />
• Concern with the presence of entrapped water is the<br />
probability of hydrogen embrittlement of the material<br />
• Moisture must be removed<br />
<strong>In</strong> <strong>Situ</strong> <strong>Francis</strong> turbine <strong>Blade</strong> <strong>Replacement</strong> | NWHA Hood River| 2013-05-23<br />
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