409 Stainless Steel Grade
ASTM A240, ASME SA240, EN 10088-2
Finish can range from: 1D (Hot rolled/free of scale), 2D (Cold rolled/smooth) to
2B (Cold Rolled/smoother than 2D). This will vary based on what our suppliers in Europe send us.
1D finish will usually fall in 3mm or thicker plate. 2D and 2B finishes will be anything under 3mm (and sometimes including 3mm).
409 is a titanium stabilized ferritic stainless steel. Although regarded as a general-purpose chromium stainless steel the primary application for 409 stainless steel is for use in automotive exhaust systems. Its uses would be in those areas where appearance is a secondary consideration to mechanical properties and corrosion resistance and where some weldability is required.
Grade 409 resists atmospheric and exhaust gas corrosion. A light surface rust will form in most atmospheres; this rust retards further corrosion but makes the surface undesirable for decorative applications. The corrosion resistance is about the same as that of 3CR12 and the 12% chromium martensitic grades such as 410, and inferior to the 17% chromium grade 430.
Automotive exhaust systems