Nippon Steel and Sumikin Stainless Corp. have won the Gold and Bronze awards in the categories for Best New Technology and Best New Development at the International Stainless Steel Forum (ISSF) held in Shanghai in May this year.
Duplex stainless steel SUS329J4L is used for the new water supply tanks built by the Bureau of Yonago City Waterworks in Tottori, Japan. They were installed on top of a mountain near the coast of the Japan Sea and will be exposed to strong seasonal sea breezes.The water stored in the tanks contains sodium hypochlorite as disinfectant. High strength was required for the material to resist pressure from the large quantities of water stored in the tanks. Duplex stainless steel is the best solution to meet all these requirements. As painting and coating are not necessary, the material eliminates maintenance costs.
Before the Great East Japan Earthquake in 2011, aluminum-alloy slide gates had been one of the main countermeasures against tsunamis, however, adoption of a new technology called âFlap-Gateâ? has been advanced after the disaster. There were three major requirements for the main material to create Flap-Gate Seawall. Firstly, as large vehicles pass over the gate, it has to have high strength against deformation and abrasion resistance. Secondly, high corrosion resistance was required to reduce the cost of painting and repairs. Thirdly, the material has to be light enough to enable the gates to flip up into position due to its natural buoyancy.
The features of NSSC2120 offered solutions to these requirements. This lean duplex stainless steel contributed to the implementation of Flap-Gate seawalls against flood disaster, by improving durability and corrosion resistance, and reducing weight simultaneously.
