409L stainless steel has excellent corrosion resistance, which is suitable for extending the life of cars and lightening cars. As a recyclable environmental protection material, GM, Ford, Volkswagen, DaimlerChrysler and other major automobile manufacturers use 100% stainless steel in the exhaust system. The automobile exhaust system is the longest part of the automobile components. The system must withstand great temperature changes (- 20~850 ℃) and high-frequency vibration of high temperature and high-speed exhaust gas. In the most complex environment with the largest changes in the automobile, the 409L can withstand a temperature limit of (- 20~650 ℃). Recently, due to the increasingly strict environmental protection standards for automobile exhaust, the increase of short distance urban driving, the distribution of snow remover in winter and other reasons, the use standard of exhaust system has become increasingly strict. From Euro II to Euro IV standards, traditional steel can not meet its technical requirements, and high-end motorcycle exhaust system has used 409L materials. The quantity of 409L stainless steel used for each vehicle is 35KGS-65KGS.