ASME Section VIII Division 1 UCS-66 Toughness Requirements: Impact Testing Exemptions, Minimum Design Metal Temperature, and Welding Procedure Implications
ASME Section VIII Division 1 UCS-66 determines whether a carbon or low-alloy steel pressure vessel must undergo Charpy V-notch impact testing. 4 exemption curves (A-D), governing thickness, MDMT plot framework. 6 welding procedure implications (QW-403.6 / consumable / QW-409.1 heat input / preheat / PWHT / test plate). 9-step decision tree + 5 common UCS-66 pitfalls + Real Project SA-203 Gr E LNG vaporizer MDMT -73°C.