The “Sunrise Hope”
Tokyo – The world’s first chemical tanker to use a combination of duplex stainless steeland stainless clad steel in the construction of its cargo tanks was successfully delivered to Oita-based Hiro Naviera S.A. (President: Tomonori Yoshimura) on 15 November2014 by Usuki Shipyard Co., Ltd (President: Jiro Kadota). The application of the duplex steels in the vessel’s cargo tanks was made possible thanks to an expansive joint research program involving steel manufacturers, leading technical universities, and ship designer, as well as ClassNK (Chairman and President: Noboru Ueda) which supported the project as part of its Joint R&D for Industry Program.
The 12, 500MT chemical tanker Sunrise Hope, owned by Hiro Naviera S.A., will be
operated by Nippon Marine Co., Ltd (President: Shinichi Igata). The eco-ship design
vessel is equipped with 14 cargo tanks, all which employ duplex stainless steel
technology. Construction of the vessel was carried out in accordance with ClassNK’s
Guidelines on Welding of Duplex Stainless Steels, which were released in January 2014,
marking the first time the Guidelines have been used in the construction of an actual
vessel.
Duplex stainless steel provides not only significantly greater strength and excellent
corrosive resistance in comparison with the commonly used austenitic stainless steel
SUS316LN, but its low nickel composition also makes it economical. Although duplex
stainless steel technology has been used previously in shipbuilding internationally, this
marks the first time in the world that a combination of both duplex and stainless clad
steels have been used in the construction of a chemical tanker’s cargo tanks. It is also
the first time that duplex stainless steels have been used in a Japanese shipyard, while
the lean duplex stainless steel which contains lower nickel compared to duplex stainless
steel have been used in some cases.
Duplex stainless steels consist of a mixture of both of austenite and ferrite phases and
offer enhanced strength and corrosion resistance superior to that of commonly used
austenitic stainless steels. On the Sunrise Hope, duplex stainless steel KSUS329J3L
replaces the commonly used SUS316LN for the bulkheads inside the cargo tanks, while
