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U.S. Department of Energy
Office of Scientific and Technical Information

New-type steel plate with ultra high crack-arrestability

Conference ·
OSTI ID:205425
; ; ; ;  [1];  [2]
  1. Nippon Steel Corp., Oita (Japan)
  2. Nippon Steel Corp., Futsu, Chiba (Japan). Steel Research Labs.
A new-type steel plate has been developed by controlling the microstructure of the surface layers. The surface layer consists of ultra fine grain ferrite microstructure, which provides excellent fracture toughness even at cryogenic temperature. When an unstable brittle crack propagates in the developed steel plate, shear-lips can be easily formed due to the surface layers with ultra fine grain microstructure. Since unstable running crack behavior is strongly affected by side-ligaments (shear-lips), which are associated with extensive plastic deformation, enhanced formation of the shear-lips can improve crack arrestability. This paper describes the developed steel plates of HT500MPa tensile strength class for shipbuilding use. Fracture mechanics investigations using large-scale fracture testings (including ultrawide duplex ESSO tests) clarified that the developed steel plates have ultra high crack-arrestability. It was also confirmed that the plates possess sufficient properties, including weldability and workability, for ship building use.
OSTI ID:
205425
Report Number(s):
CONF-950695--; ISBN 0-7918-1309-6
Country of Publication:
United States
Language:
English