ISSUE 2/2015

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Papis, K. J.; Tunzini, S.; Menk, W. Development of ductile cast iron for high-temperature applications

New ductile iron grades are required to meet the challenges arising from engine downsizing and subsequent temperature increase. This paper describes the development of new ferritic, temperature resistant ductile iron grades, their properties, serial applications and newest achievements in material development. Downsizing of gasoline and diesel engines helps to reduce CO2-emissions. Constructing smaller engines with increased power levels leads to higher exhaust gas temperatures. In passenger cars, these exceed 850 °C in diesel engines and even 1050 °C in turbocharged gasoline engines. Thermal insulation protects the engine’s surroundings, but tightens the operating conditions of the insulated hot parts even further. Ferritic silicon- and molybdenum-alloyed ductile iron grades are standardized in Europe in EN-16124. However, these materials’ properties are not sufficient for being applied in the newest downsized engines. Based on SiMo ductile iron, new ferritic materials are developed with the aim to raise ferrite/austenite transition temperature, high temperature (HT) strength and scaling resistance.

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