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Environmental Management
Environmental Sustainability Report 2004

Contribution to Environmental Protection through Products, Technologies and Services (1)


Eco-Materials
Development of Heat-Releasing Steel Sheet Kobehonetsu and Heat-Releasing Aluminum Sheet Kobehonetsu Aluminum


The recent electronic apparatus generates a large amount of heat, possibly results in shortened life and degraded performance of precision parts. Kobe Steel is the first company in the world to succeed in developing and commercializing a material Kobehonetsu that is seven times more effective at releasing heat than conventional electrogalvanized steel sheet. The heat-releasing property is as high as charcoal, a material with the world's highest emissivity.

Aspecial chemical coating treatment greatly increases heat absorption and improves product capabilities, enabling the number of layers in multilayer circuits to be increased; and cooling fan motors to be downsized or reduced. This saves electricity and reduces noise. Flexibility in designing devices increases and the eco-design of products is substantially advanced.

Furthermore, the special coating treatment has also been applied to aluminum. Kobehonetsu Aluminum has a heat emissivity 20 times higher than conventional untreated aluminum sheet.

 

Features of Kobehonetsu Aluminum versus steel sheet
Electrogalvanized steel sheet A5052 alloy aluminum sheet
Untreated Honetsu-treated Untreated Honetsu-treated
Specific gravity 7.85 7.85 2.68 2.68
Heat conductivity
(W/m-K)
60 60

140

140
Emissivity 0.12 0.86 0.04 0.86
Effective
heat source position
Extensively dispersed Partially localized

"Kobehonetsu" wins the Iwatani-Naoji Memorial Prize.

Kobehonetsu, a distinctive steel product, received the prestigiousth Iwatani Naoji Memorial Prize in 2003, owing to the practical application of effective energy utilization. The Prize is administered by the Iwatani Naoji Foundation.


Lead-free Free-cutting Steel for Automobiles

Leaded free-cutting steel is used for automobile seat parts, motor shafts, and others because of its beautiful finished surface and fine chips. However, in compliance with the End-of-Life Recycling Initiative*," the amount of lead in new automobiles must be reduced by the end of 2005.
Kobe Steel developed a lead-free free-cutting steel, which provides cutting efficiency and other qualities equal to leaded free-cutting steel by using sulfides in place of lead in the ladle refining stage making the best of its specialty steel technologies.


*) End-of-Life Recycling Initiative: The recycling ratio of usable materials such as ferrous and nonferrous metals from used automobiles shall be increased from the current 75-80% to 95% in 2015 (April 1997, Ministry ofInternational Trade and Industry).

Comparison of machineability of lead-free free-cutting steel

Conventional lead-free free-cutting steel produces long extended cuttings that tangle around the machine and reduces productivity. In the examples, the cuttings of the new steel are shorter than leaded free-cutting steel. This enables productivity to be equal to leaded free-cutting steel.