Development and application of medium silicon molybdenum niobium ductile iron exhaust manifold

Through the research on the optimization of the composition ratio of existing silicon-molybdenum ductile iron materials and high-nickel austenitic ductile iron materials, as well as the addition and experimental verification of trace alloying elements, a new type of medium-silicon molybdenum niobium ductile iron material has been obtained and successfully applied to the manufacturing and industrialization of various medium and highend engine exhaust manifolds. This new type of medium-silicon molybdenum niobium ductile iron material has superior temperature resistance and thermal fatigue resistance, replacing the corresponding products made of highnickel austenitic ductile iron materials at temperatures of 760～820℃, significantly reducing the manufacturing cost of the corresponding products. At 780℃, the tensile strength of the corresponding products is ≥70MPa, and the yield strength is ≥50MPa. Meanwhile, in the process of developing and applying this new type of medium-silicon molybdenum niobium ductile iron material in the products of customers such as FAW Jiefang and Faurecia, the research and application of related technologies have achieved good economic and social benefits.