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Crack initiation and arrest characteristics of 9% Ni steels with various Charpy v-notch energy valves

Journal Article · · Adv. Cryog. Eng.; (United States)
OSTI ID:6018423

Nine percent Ni steel, used in the construction of LNG tanks where brittle fracture can result in catastrophic damage, requires a high fracture toughness. The materials tested in this study for a steel with this property are quenched and temepred (QT), double normalized and tempered (NNT), and as rolled 9% Ni steel plates. The crack initiaton, propagation, and arrest charactristics of these plates at 103 K were studied with respect to the 2-mm V-Notch Charpy impact energy at 77 K. Among the results are 1) that the increase in the Charpy impact energy, mainly attained by reducing the sulfur content, improves the resistance to ductile crack initiation and propagation for the QT steels; 2) that the QT steels have larger crack opening displacement values than NNT and as-rolled steels even when the Charpy impact energy is the same; and 3) that all QT steels tested arrest the brittle crack that runs 350 mm in the starter section at a stress as large as 490 MPa. Chemcial composition table and test plots are given. Weldability is analyzed.

Research Organization:
Kawasaki steel Corporation, Chiba
OSTI ID:
6018423
Journal Information:
Adv. Cryog. Eng.; (United States), Journal Name: Adv. Cryog. Eng.; (United States) Vol. 28; ISSN ACYEA
Country of Publication:
United States
Language:
English