A515 Gr.65 is primarily specified for boiler components that operate at intermediate temperatures where post-weld heat treatment (PWHT) is applied. Its main applications include:
Boiler Shells and Drums: For sections operating at elevated pressures and temperatures below critical creep ranges.
Headers and Manifolds: Where controlled silicon content provides good strength and oxidation resistance.
Non-Heat-Exposed Support Structures: Certain internal supports and brackets within the boiler setting.
It is typically not used for superheater or reheater tubes exposed to the highest temperatures, where chromium-molybdenum alloys are required.
Critical Quality and Compliance Requirements
To ensure safe operation, A515 Gr.65 for power plant use must meet exacting standards:
Material Certification: Plates must be supplied with a complete Mill Test Certificate (MTC) compliant with ASTM A515/A515M and, for ASME code construction, SA-515 Gr.65.
Heat Treatment: Plates are typically supplied in the normalized condition to achieve a uniform grain structure and consistent mechanical properties essential for high-temperature service.
Enhanced Testing: Beyond standard tensile tests, projects often require:
Ultrasonic Testing (UT): For detecting internal laminations or discontinuities.
Additional Impact Testing: Even though not standard for A515, many boiler specifications (e.g., EN 10028-2) or client standards may mandate Charpy V-notch tests at ambient or specified temperatures to ensure adequate toughness.
