| November 19, 1998 |
SP-700 Titanium Alloy Chosen for Next-Generation Japanese RocketNKK's new titanium alloy SP-700, which features excellent superplastic formability, has been adopted as a composite gas tank material for the H2A, Japan's next-generation rocket. NKK received an order for the alloy from Mitsubishi Heavy Industries, Ltd.(MHI) which will supply the gas tanks (56cm-diameter spherical tanks to store gas for operating engine valves). This is NKK's first order for SP-700 for use in the domestic aerospace field. The H2A project has been directed by the National Space Development Agency of Japan, with MHI participating in the manufacture of the rocket.The first H2A is slated for launch in early 2000 as the successor to the present H2 rocket. The new rocket will feature a redesigned body, changes in materials and production processes, and overseas procurement in an attempt to drastically reduce costs. NKK's high-formability SP-700 alloy, which has already been patented in Japan,the United States and Europe, has been chosen as an optimal material for the project. Up to now, Ti-6Al-4V alloy has been the major titanium alloy for aerospace applications. However,it suffers from poor workability in fabrication and a very high working temperature. By comparison,SP-700 exhibits remarkable superplasticity below 800°C, more than 100°C lower than Ti-6Al-4V.Combining this merit with "optimal sheet thickness design technology" and "superplastic-forming sheet width and thickness control technology" developed by MHI, the composite gas tanks will be succcessfully produced using SP-700 at reduced cost. Since developing SP-700 in 1989, NKK has succeeded in marketing it for use in commercial products, including golf club heads, mountaineering equipment and wrist watch cases, while seeking to expand the market to the aerospace industry. As part of such a move, in January NKK set up a new U.S. subsidiary, NKK Titanium U.S.A.Corporation. Through this company, NKK has formed a business alliance with Ohio-based RMI Titanium Company to cultivate U.S. and European aviation markets and further expand sales of SP-700 in aerospace fields both at home and overseas. |
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