Award winner
Duplex Stainless Steel Gate Facilities for Tsunami Disaster Prevention
 Applicant: Tohoku Branch, Hitachi Zosen Corporation
Reason for selection:
At the time of The Great East Japan Earthquake in 2011, extensive damage was caused by tsunami mainly along the coast of northeastern part of Japan. Taking a lesson from the catastrophe, construction of infrastructure for tsunami disaster prevention is being promoted throughout the country.
The gate facility called land gate is one of such structures. Land gates are kept open in ordinary times allowing pedestrians and automobiles to pass but are closed in emergency situations to protect local communities. Since the Great Earthquake, studies have been made for operational improvements including the opening and closing of gates at the time of tsunami and for adopting new technologies in terms of their materials and structural designs.
One such design is “floating type” flap gate, which utilizes the flotation of the gate itself and enables automatic opening and closing without external power. This fundamentally solves a social problem of disaster associated with the gate-handling.
To put gates of this design into practical use, however, it was necessary to satisfy two contradicting characteristics; namely, compared with conventional facilities, the gate doors must be lighter in weight on one hand and must be higher in strength and abrasion resistance on the other. The development of duplex stainless steel with high strength and high hardness has made a great contribution to commercializing “floating type” flap gates and overturning the prevailing orthodoxy that “aluminum alloy has an advantage in terms of weight reduction”, which has drastically raised the potential and attractiveness of stainless steel as a material for such and other related applications.
Stainless steel types used: SUS821L1 (NSSC2120), SUS329J4L..

Consumption:  Max. 50 tons/gate
Presenter: Nippon Steel & Sumikin Stainless Steel Corporation
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