Forged vs. Cast Valve Bodies
Customers of Combined Cycle Power Plants have indicated that Type 91 gate valves have been experiencing shorter than anticipated life cycles. These valve bodies are traditionally cast in A217 C12A material.
The solution is to switch to a forged body. Therefore, TRILLIUM Valves USA introduced the Atwood & Morrill® Forged Gate Valve. At temperatures above 1,000° F a forged body is superior because;
- Imperfections inherent to all castings impose greater risk in C12A applications due to the elevated temperatures and increased thermal cycling.
- Stringent code and customer requirements for C12A make it costly and cumbersome to process.
- Forged Type 91 material will have a higher initial hardness level than C12A castings due to differences in how the materials are processed indicating a longer life cycle.
Forged valve bodies help minimize material defects and provide better quality and longer life valves, especially at elevated temperatures with thermal cycling conditions.
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