SEN Wide-Plate Crack-Arrest Tests Using A 533 Grade B Class 1 Material: WP-CE Test Series.

摘要

Two 102-mm-thick wide-plate crack-arrest tests (WP-CE series) are discussed in the report. Each test used a 1 x 1 x 0.1 m thick single-edge notched specimen (a/w = 0.2) fabricated from A 533 grade B class 1 steel that was subjected to a linear thermal gradient along the plane of crack propagation. The tests were conducted at the National Institute of Standards and Technology and were designed to provide fracture-toughness measurements at temperatures approaching or above the onset of the Charpy upper-shelf regime in a rising toughness region and with an increasing driving force. Results obtained from these tests have produced crack-arrest toughness values well above the limit recognized by the current ASME guidelines (220 MPa times the square root of m) with arrests occurring at 58 to 95 C above the material RTNDT (-35 C). The fracture data support (1) the use of fracture mechanics concepts to analyze cleavage run-arrest events, (2) the treatment of cleavage run-arrest and ductile fracture modes as separate events, and (3) the fact that cleavage arrest occurs above the ASME limit.