The procurement must be governed by the base material specification ASTM A515/A515M Grade 65. For pressure vessel applications, this translates to ASME Boiler and Pressure Vessel Code Section II, Part A: SA-515/SA-515M Gr.65. The Mill Test Certificate (MTC/Certificate of Compliance) is a non-negotiable document that must confirm compliance with this specification, including the required normalized or stress-relieved heat treatment condition.
Critical Technical Requirements for High-Temp Service
Beyond the standard chemical and mechanical property checks (C, Mn, Si, tensile/yield strength), procurement for high-temperature tanks demands additional due diligence:
Enhanced Ultrasonic Testing (UT): Specify ASTM A578/A578M Level II or higher for straight-beam ultrasonic inspection. This is critical for detecting internal laminations and inclusions that could compromise integrity under prolonged thermal stress.
Potential Impact Testing: While not a default requirement of A515, many engineering contractors mandate supplementary Charpy V-Notch impact testing (e.g., at 20°C or 0°C) per ASTM A370 to verify adequate fracture toughness for the specific design conditions.
Traceability and Marking: Ensure each plate is clearly marked with the heat number, grade, standard, and manufacturer's identity for full traceability from mill to fabrication and throughout the tank's service life.
A robust purchase order (PO) should explicitly state:
Full material designation: ASME SA-515 Gr.65, Normalized
Required supplemental testing: UT to A578 Level II, Impact Testing as per [Project Spec]
Delivery of a complete, original MTC and UT Report
Applicable design codes (e.g., ASME Section VIII, Div. 1)
