Research and Design of Corrosion Resistant for Automobile Exhaust Pipe
WEN Aimin;XIE Jian;HU Jun;Nanjing Communications Institute of Technology;
Through the method of single and composite adding of Mo and Cu,the pitting corrosion and stress corrosion resistance behavior of car's exhaust system in the chloride ion corrosion medium were studied. By aging treatment method,the separation behavior of alloying elements and its role in the local corrosion mechanism were studied. The results show that the single adding of Mo or Cu can improve the corrosion resistance of exhaust pipe steel. The composite adding of Mo + Cu can inhibit the corrosion of exhaust pipe steel in chlorine ion to a certain extent,which shows better effect than single adding Cu element,but Cu element should not be more than 0.19%. With the extension of aging time,the stress corrosion cracking way gradually shifts from transgranular fracture to the intergranular fracture priority with transgranular mixed fracture. The crack originates from some corrosion pits and extends along the pitting corrosion pit.