AISI 409 Stainless Steel Material Data Sheet (Ferritic, Annealed)

AISI 409 Designation

AISI 409, wrought
Condition	Annealed
UNS number	S40900
US name	~ASTM S40977, ~ASTM S40976, ~ASTM S40975, ~ASTM S40900, ~ASME 409
EN name	~X6CrNiTi12, ~X2CrTi12
EN number	1.4512, ~1.4003
ISO name	~X6CrNiTi12, ~X2CrTi12

AISI 409 Typical uses

Exhaust components and silencers, catalyst boxes, clip fasteners, fire doors, furnace parts, heating and ventilation equipment, heat shields, petroleum and chemical plant trays and separators, tubing.

AISI 409 Composition detail

C (carbon)	0	–	0.08	%
Cr (chromium)	10.5	–	11.8	%
Fe (iron)	84.8	–	89.5	%
Mn (manganese)	0	–	1	%
Ni (nickel)	0	–	0.5	%
P (phosphorus)	0	–	0.045	%
S (sulfur)	0	–	0.03	%
Si (silicon)	0	–	1	%
Ti (titanium)	0	–	0.75	%

AISI 409 Physical properties

Density

7.61

–

7.82

g/m3

AISI 409 Mechanical properties

Young’s modulus	195	–	205	GPa
Specific stiffness	25.2	–	26.7	MN.m/kg
Yield strength (elastic limit)	205	–	295	MPa
Tensile strength	415	–	495	MPa
Specific strength	26.6	–	38.3	kN.m/kg
Elongation	17	–	25	% strain
Compressive strength	205	–	295	MPa
Flexural modulus	195	–	205	GPa
Flexural strength (modulus of rupture)	205	–	295	MPa
Shear modulus	75	–	81	GPa
Bulk modulus	144	–	159	GPa
Poisson’s ratio	0.275	–	0.285
Shape factor	63
Hardness – Vickers	140	–	185	HV
Hardness – Rockwell B	75	–	88	HRB
Hardness – Rockwell C	0	–	10	HRC
Hardness – Brinell	170	–	188	HB
Elastic stored energy (springs)	108	–	212	kJ/m3
Fatigue strength at 10^7 cycles	231	–	262	MPa
Fatigue strength model (stress range) Parameters: Stress Ratio = -1, Number of Cycles = 1e7cycles	205	–	296	MPa

AISI 409 Impact & fracture properties

Fracture toughness	76	–	135	MPa.m0.5
Toughness (G)	30.8	–	85.5	kJ/m2

AISI 409 Thermal properties

Melting point	1480	–	1530	°C
Maximum service temperature	700	–	750	°C
Minimum service temperature	-73	–	-43	°C
Thermal conductivity	24	–	28	W/m.°C
Specific heat capacity	450	–	500	J/kg.°C
Thermal expansion coefficient	10.5	–	12.5	µstrain/°C
Thermal shock resistance	87.9	–	131	°C
Thermal distortion resistance	2.02	–	2.54	MW/m
Latent heat of fusion	260	–	285	kJ/kg

AISI 409 Electrical properties

Electrical resistivity	55	–	65	µohm.cm
Electrical conductivity	2.65	–	3.13	%IACS
Galvanic potential	-0.31	–	-0.23	V

AISI 409 Magnetic properties

Magnetic type

Magnetic

AISI 409 Optical, aesthetic and acoustic properties

Transparency	Opaque
Acoustic velocity	5020	–	5160	m/s
Mechanical loss coefficient (tan delta)	0.00109	–	0.00144

AISI 409 Processing properties

Metal casting	Unsuitable
Metal cold forming	Acceptable
Metal hot forming	Acceptable
Metal press forming	Excellent
Metal deep drawing	Acceptable
Machining speed	33.5 m/min
Weldability Notes: Preheating and post weld heat treatment are not required	Good
Weldability – MIG	Fair
Weldability – plasma	Fair
Weldability – SAW	Not recommended
Weldability – TIG	Fair
Brazeability	Fair
Carbon equivalency	0.35 – 0.548

AISI 409 Durability

Water (fresh)	Excellent
Water (salt)	Excellent
Weak acids	Excellent
Strong acids	Acceptable
Weak alkalis	Excellent
Strong alkalis	Limited use
Organic solvents	Excellent
Oxidation at 500C	Excellent
UV radiation (sunlight)	Excellent
Galling resistance (adhesive wear) Notes: Aluminum bronze is the most suitable mating material to minimize galling.	Limited use
Flammability	Non-flammable

AISI 409 Corrosion resistance

Pitting resistance equivalent number (PREN)	10.5 – 11.8
Pitting and crevice corrosion	Low (<20)
Stress corrosion cracking Note: Rated in chloride; Other susceptible environments: Hydrogen sulfide	Not susceptible
Intergranular (weld line) corrosion	Moderate
Inorganic acids	Restricted
Organic acids	Restricted
Alkalis	Moderate
Humidity / water	Good
Sea water	Good
Sour oil and gas	Restricted

AISI 409 Standards with similar compositions

Australia: 409 to AS 1449

China: 00Cr12Ti to GB/T 12770, 0Cr11Ti to GB 4238

Hungary: H18 to MSZ 4359

International: X6CrTi12E to ISO 4954

Italy: X6CrTi12 to UNI 8317

Spain: F.3112 to UNE 36016/2, F.3121 to UNE 36016/2

USA: S40900 to ASTM A959, S40900 to SAE J405, S40920 to ASTM A240/A240M, S40930 to ASTM A959, S40940 to ASTM A493-95, S40940 to ASTM A959, TP409 to ASTM A268/A268M, TP409 to ASTM A803/A803M, UNS S40800, UNS S40900, UNS S40910, UNS S40920

Tradenames: ATI 409HP, E C S, ES 409 DFP, FERROTHERM 4720, NIROSTA 4512, RDN 509, SPARTAN REDHEUGH 409S19, UGINOX F 12 T