Description
Stainless Steel 409 ,UNS S40900, SS 409 Chemical Composition
Fe, <0.08% C, 10.5-11.75% Cr, <0.5% Ni, <1.0% Mn, <1.0% Si, <0.045% P, <0.03% S, 6x%C-0.75% Ti
What is SS 409 stainless steel
SUS409 stainless steel is a Ferritic steel that offers good mechanical properties and high-temperature corrosion resistance. It is commonly considered as a chromium stainless steel, with applications in exhaust systems of automobiles and applications that demand weldability.
SUS409 steels are also available in highly stabilized forms, such as grades S40930, S40920 and S40910. The stability of these grades is provided by the presence of niobium, titanium, or both, in the composition of steels.
UNS S40900 Properties
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| SS 409 | 450 | 240 | 25 | 75 | 131 |
Physical Properties
| Grade | Density (kg/m3) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m/°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) | |||
| 0-100°C | 0-315°C | 0-538°C | at 100°C | at 500°C | |||||
| SS409 | 7800 | 200 | 11.0 | 11.7 | 12.4 | 25.8 | 27.5 | 460 | 600 |
Grade Specification Comparison
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| SS409 | S40900 | 409S19 | – | 1.4512 | X6CrTi12 | – | SUH 409 |
Possible Alternative Grades
| Grade | Properties |
| 3CR12 | Easy to weld and good corrosion resistance. Heavy sections are more easily available when compared to 409. |
| SUS304 | High heat resistance and corrosion resistance. Grade 304 is expensive. |
| SUS321 | Better heat resistance when compared to 304 or 409. |
| Aluminized steel | Cheaper than grade 409 stainless steel, but less resistant to exhaust gases. |
