Corrosion Behaviour of Ferritic Stainless Steels for Automotive Exhaust System at Condensed Water Containing Dissolved Aluminium

摘要

Automotive exhaust muffler and tail pipe are categorized into cold end parts of the exhaust system where the operating temperature is from room temperature up to 600°C. The cold end parts are often operated in the temperature range where exhaustive gas could be condensed to form corrosive water. In some countries using low-grade fuel leading to higher concentration of corrosive species in the condensed water, type 436L containing 17.5% Cr and 1.0% Mo has been extensively applied for the cold end parts because of its excellent corrosion resistance. However, due to its higher price than type 409L and 439 stainless steels, alternatives for type 436L such as aluminized ferritic stainless steels are often considered as candidate materials for the cold end parts.