PROCEDURE IMPROVES LINE PIPE CHARPY TEST INTERPRETATION

The Charpy V-notch (CVN) impact test is a method of characterizing a line-pipe material's notch toughness and resistance to fracture growth. Although CVN testing of line pipe material is routine, test results are sometimes misinterpreted because of specimen size and load rate on actual toughness transition behavior. This procedure is useful when the toughness transition curve is incomplete or nonexistent. Toughness data may be incomplete because the API 5L toughness test establishes minimum performance at a single temperature, which does not reveal the full transition curve. The method described here has been used successfully to solve problems encountered by several pipeline operators.