Demonstration Test of Performance of World’s First Titanium Building Materials with Discoloration Resistance

Jun. 30, 2016

Nippon Steel & Sumitomo Metal Corporation


Demonstration Test of Performance of World’s First Titanium
Building Materials with Discoloration Resistance


Nippon Steel and Sumitomo Metal Corporation (NSSMC) developed titanium with discoloration resistance in 2001. This year, 15 years have passed since it was used for the first time in the world in the Oita Bank Dome. Therefore, on this occasion, NSSMC carried out research on color changes in the titanium roof and demonstrated that the roof is currently still displaying good discoloration resistance performance.

The use of titanium for building materials (roofs and walls) began in the 1970s. At the start of the 1990s, a phenomenon where some previously built titanium roofs changed from a silver color to a brown color was confirmed. This phenomenon is caused by oxide film that is present on the titanium surface reacting with acid rain and growing, and the color of the surface that was silver appearing brown because of light interference.

NSSMC elucidated this color change mechanism, established technology to remove impurities from the titanium surface layer that is the cause of color change, and as a result, succeeded in developing titanium with discoloration resistance for the first time in the world in 2001. This technology was used for the first time in the Oita Bank Dome in the same year, and as 15 years have now passed since the completion of construction, NSSMC conducted research on the state of changes in the color tone of the titanium roof. As a result of observing and studying several locations on the roof of the Oita Bank Dome, we confirmed that there has been very little color change and that the titanium surface remains beautiful and sound even now, 15 years since the completion of construction.

NSSMC’s titanium building materials are lightweight (their specific gravity is 60% that of steel and 50% that of copper) and contribute to safety and security (including the contribution made through enhanced efficiency and shorter labor time for multi-level building construction work, mitigation of loads on framework structures through seismic resistance enhancement, and improvement of environmental friendliness). In addition, NSSMC has realized life cycle cost (LCC) improvements (reduction of the maintenance burden) through advances in design and the superior discoloration resistance of titanium materials. NSSMC is looking forward to further promoting the diffusion of titanium products in Japan and overseas.

【Overview of Oita Bank Dome】


Location: Oita City, Oita Prefecture
Titanium parts/construction method: Roof/welded panel
Area of titanium use: 32,000 m2
Quantity of titanium used: 53 tons
Surface: Roll Dull (ND20)
Completion: March 2001





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