Evaluating the Effectiveness of New ASTM A350 Supplementary Requirements on Flange Impact Testing Consistency

Abstract In recent years, major capital projects have experienced a rise in low toughness incidents involving ASTM A-350 LF2 Cl1 flanges. These issues are often difficult to trace due to the complex metallurgical interactions during forging, heat treatment, and on-site welding. However, some cases suggest the problem lies not in actual material toughness but in discrepancies between manufacturers’ certified impact test results and those obtained from actual flanges during welding procedure qualification tests or material screening tests at construction sites. This points to poor representativeness of test specimens used for certification. To address this, the October 2024 revision of ASTM A350 introduces new provisions and supplementary requirements aimed at improving the consistency of impact testing for ASME B16.5 flanges. This study aims to evaluate whether these updates help reduce disparities in impact values, especially between certified flanges and separate test blanks. Four flanges—two closed-die forged and two ring-rolled—were tested to identify the most demanding test locations and orientations under the new standard. The study also compares impact test results of actual flanges and test blanks. This work underscores the importance of collaboration between forging manufacturers and EPC contractors to define effective quality control measures and reduce project risks related to low toughness events that could jeopardize project timelines.