Cast Iron Alloys for Exhaust Applications

Abstract

Downsizing of engines – gasoline as well as Diesel - helps to reduce CO2-emissions. Smaller engines at the same or even raised power levels result in higher exhaust gas temperatures. In personal cars, these are raised to above 850°C in Diesel engines and up to 1,050 °C for turbocharged gasoline engines. Ferritic Si- and Mo-alloyed ductile iron grades are standardised in Europe in EN-16’124. However, these materials are not sufficient for highly turbo charged engines. Based on SiMo ductile iron, new ferritic materials have been developed to raise ferrite/austenite transition temperature, high temperature strength and scaling resistance. The paper describes the development of new ferritic high temperature ductile iron grades, their properties, serial applications and newest achievements in realizing even higher working temperatures.