Stainless steel 409

409 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.

409 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.

Chemical Composition

Grade		C	Mn	Si	P	S	Cr	Ni	Ti
409	min. max.	- 0.08	- 1.00	- 1.00	- 0.045	- 0.045	10.5 11.75	- 0.5	6x C 0.75

Mechanical 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
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
409	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
409	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.
304	High heat resistance and corrosion resistance. Grade 304 is expensive.
321	Better heat resistance when compared to 304 or 409.
Aluminized steel	Cheaper than grade 409 stainless steel, but less resistant to exhaust gases.