BACKGROUND

Nippon Steel is one of the world's largest producers of crude steel, but it has been aggressively pursuing the advanced composites market, both as a supplier of pitch based carbon fiber and carbon fiber based products (such as rollers, structural profiles, rods, cables etc.) and as a producer of materials that could replace steel in the future. Research and development is conducted through the Technical Development Bureau of which the Advanced Technology Research Laboratories are an integral part. These laboratories are based in Kawasaki, Sagamihara, Hikari and Futtu. Research is conducted in the areas of electronic materials, circuit design, chemicals (composites falls into this area), advanced ceramics and metals, materials analysis and computational simulation, and activities for the future (including genetic engineering and mesoscopic materials).

ACTIVITIES OF INTEREST

• Nippon Steel is a supplier of pitch based carbon fiber to Tonen for the production of tow sheet used in infrastructure rehabilitation. In sheet form it has an areal weight of 300 g/m2, tensile modulus of 5 x 106 kg/cm2 and a 0.5% strain-to-failure level. The pitch fiber is supplied by a new subsidiary - Nippon Graphite Fiber Corporation, formed by Nippon Steel Corporation and Nippon Oil Corporation. They expect the higher modulus sheet to be used extensively in the retrofit of deteriorating concrete slabs and bridge decks.
• A plant was constructed in 1996 at the company's Hirohata Works to produce carbon fiber reinforced plastic products used for building materials and industrial structural materials. The plant includes filament winders capable of manufacturing pipes of length over 10 m - reputed to be the largest in Japan. The plant's annual production capacity in terms of carbon fiber throughput is 200 tons.
• Nippon Steel supplies carbon fiber based composite strands for tendons and cables (NACC). These are being supplied in a collaboration with Suzuki Metal Industry Co., Ltd. and are available in 7, 19 and 37 wire twisted configurations. This activity is an integral part of the ACC organization.
• The company is a supplier of a carbon fiber based cable reinforcing system for shafts that can be easily cut by a shield/bore thereby decreasing wear of the shield cutter (as compared to steel) and increasing the overall efficiency of tunneling operations. The product is called NOMST- Novel Material Shield-cuttable Tunnel-wall system and is reported to be widely used and the best example of commercial viability and success of a carbon fiber reinforced composite product in the civil infrastructure market.
• Nippon Steel is working on the use of high modulus carbon fiber rods as vertical reinforcement for hollow mortar-based wall panels that provide smaller deflections under external wind and horizontal forces. This is still experimental although two demonstrations have been built: the electrical chamber in one of the company's factories, and a penthouse in a shopping store in Kyushu with an area of 100 m2.
• Nippon Steel is investigating the use of carbon fibers for cables used as launching cables in large bridge structures. A cost model and analysis of the economics of such carbon fiber based systems is also being developed.