Steel for automobile exhaust systems

Car exhaust systems mainly use ferritic stainless steel

Ferritic stainless steel is widely used in automobile exhaust emission systems. Currently, ultra-pure ferritic stainless steel of low chromium and medium-high chromium series are mainly used. In the past 30 years, Europe and Japan have developed a large number of ferritic stainless steels and widely used them in automobile exhaust systems, making the automobile exhaust system 100% stainless steel. At present, low-chromium and medium-high-chromium series ferritic stainless steels for automobile exhaust systems have been formed in Japan and Europe.

The main manufacturers of ferritic stainless steel for automobile emission systems are represented by Baosteel, Taiyuan Steel, JFE, NSS, NSSC, POSCO, GNEE and ARCELOR. There are two types of steel, one is low chromium series such as SUH409L, etc., and the other is medium chromium series such as SUS429, SUS432L, SUS439L, SUS436L, SUS441, etc.

According to the ambient temperature of use, the main stainless steel products used for low to medium temperatures include SUH409L, SUS439L, SUS432L, SUS436L, etc. The main steel types used for medium and high temperatures include SUS436L, SUS429, SUS441, SUS434, etc. Among them, the 409 series of low-chromium ferritic stainless steel is the most widely used because of its economical and practical advantages. The usage of low-chromium 409 ferritic stainless steel accounts for about 50~60% of the usage of all automobile exhaust systems. about.

The corrosion resistance of medium-chromium ferritic stainless steel series, especially stainless steel such as SUS436L, which is added with corrosion-resistant alloy Mo, has been further improved. Medium chromium SUS439 stainless steel is more favored by OEMs because it has better corrosion resistance than 409L and lower manufacturing cost than 436L.