Evaluation of Ferritic Stainless Steel Performance in Exhaust Environment

In current scenario, there is trend to use stainless steels in place of carbon steels and aluminized carbon steels for Exhaust application. In response to changing regulatory requirements and durability performance requirements of exhaust systems, the ferritic stainless steels are proven to be best suited for the purpose. There are multiple ferritic stainless steels available as options for exhaust system. The material in an exhaust system is subject to heat, oxidation, corrosion and condensate. These environment condition demands that exhaust material should possess high temperature corrosion and oxidation resistance along with required mechanical performance such as vibration and thermo-mechanical load cycles. This work is an attempt to develop simulated test methods for corrosion and thermal environment and evaluate performance of commonly used ferritic stainless steels. The ferritic stainless steels, in this study, were subjected to corrosive media and synthetic exhaust environment. Specific test conditions with respect to chemical concentration and thermal cycles were used to simulate exhaust conditions. The results showed improvement in performance of ferritic stainless steel grades with increase in chromium content. The study also provided comparative performance of ferritic stainless steel grades at different temperatures. The relative performance derived from the study can be used to select the right exhaust stainless steel material for the exhaust system.