Title: Development of heat-resistant cast steel for exhaust manifolds

Authors: M. Ike, K. Akiyama, K. Ohtsuka, K. Itoh

Addresses: Materials Research Laboratory, Central Engineering Laboratories, Nissan Motor Company, 6-1 Daikoku-cho, Tsurumi-ku, Yokohama-shi, Kanagawa-ken 230, Japan. ' Materials Research Laboratory, Central Engineering Laboratories, Nissan Motor Company, 6-1 Daikoku-cho, Tsurumi-ku, Yokohama-shi, Kanagawa-ken 230, Japan. ' Advanced Materials Research Laboratory, Hitachi Metals, 11 Kinugaoka, Moka-shi, Tochigi-ken 321-43, Japan. ' Advanced Materials Research Laboratory, Hitachi Metals, 11 Kinugaoka, Moka-shi, Tochigi-ken 321-43, Japan

Abstract: This paper presents a new heat-resistant cast steel developed for exhaust manifolds. Increased exhaust-gas temperatures accompanying recent trends towards leaner combustion and higher engine output have placed a severe thermal load on the exhaust manifold and turbocharger housing. The new cast steel displays better resistance to thermal fatigue than conventional ductile cast irons (DCI) and better cost performance than Ni-Resist (ASTM A439 austenitic ductile cast irons). In the material-design process, the properties required of the material were determined on the basis of statistical analyses. An experiment was then conducted using a test specimen that partially modelled an actual exhaust manifold and a heating simulation was carried out separately from the engine using an exhaust-system simulator. Finally, an endurance test was conducted on an actual exhaust manifold made of the new cast steel using a production system.

Keywords: cast steel; cost reduction; ductile cast iron; exhaust manifolds; heat resistance; oxidation resistance; steel castings; thermal fatigue life; thermal load; automotive exhausts; automobile industry; vehicle design; materials design; heating simulation.

DOI: 10.1504/IJMPT.1991.036638

International Journal of Materials and Product Technology, 1991 Vol.6 No.3, pp.243 - 256

Published online: 05 Nov 2010 *

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