Stainless steel, duplex, AISI 329, annealed

AISI 329 Duplex Stainless Steel Designation

AISI 329, wrought
Condition	Annealed
UNS number	S32900
US name	SAE 329, ASTM S32900, ~ASTM S32950, ~ASTM F52
EN name	X8CrNiMo27-5
EN number	~1.4460
ISO name	X3CrNiMoN27-5-2
GB (Chinese) name	0Cr26Ni5Mo2
JIS (Japanese) name	SUS329J1TP, ~SUS329J4L, ~SUS329J3L

AISI 329 Duplex Stainless Steel Typical uses

Processing of potentially corrosive liquids e.g. chemicals/oil/beverages/sewage, structural uses in corrosive environments, e.g. nuclear plants, ships, offshore oil installations, underwater cables and pipes

AISI 329 Duplex Stainless Steel Composition detail

C (carbon)	0	–	0.08	%
Cr (chromium)	23	–	28	%
Fe (iron)	63.1	–	74	%
Mn (manganese)	0	–	1	%
Mo (molybdenum)	1	–	2	%
Ni (nickel)	2	–	5	%
P (phosphorus)	0	–	0.04	%
S (sulfur)	0	–	0.03	%
Si (silicon)	0	–	0.75	%

AISI 329 Duplex, annealed, Stainless Steel Physical properties

Density

7.7

–

7.9

g/cm3

AISI 329 Duplex, annealed, Stainless Steel Mechanical properties

Young’s modulus	189	–	204	GPa
Specific stiffness	24.2	–	26.2	MN.m/kg
Yield strength (elastic limit)	500	–	600	MPa
Tensile strength	650	–	795	MPa
Specific strength	64.1	–	77	kN.m/kg
Elongation	20	–	35	% strain
Compressive strength	500	–	600	MPa
Flexural modulus	189	–	204	GPa
Flexural strength (modulus of rupture)	500	–	600	MPa
Shear modulus	74	–	81	GPa
Bulk modulus	134	–	152	GPa
Poisson’s ratio	0.265	–	0.275
Shape factor	42
Hardness – Vickers	144	–	160	HV
Hardness – Rockwell B	75	–	85	HRB
Hardness – Rockwell C	0	–	4	HRC
Hardness – Brinell	130	–	150	HB
Elastic stored energy (springs)	639	–	913	kJ/m3
Fatigue strength at 10^7 cycles	316	–	365	MPa
Fatigue strength model (stress range) Parameters: Stress Ratio = -1, Number of Cycles = 1e7cycles	274	–	421	MPa

AISI 329 Duplex, annealed, Stainless Steel Impact & fracture properties

Fracture toughness	71	–	110	MPa.m0.5
Toughness (G)	26.7	–	59.3	kJ/m2

AISI 329 Duplex, annealed, Stainless Steel Thermal properties

Melting point	1380	–	1450	°C
Maximum service temperature	740	–	787	°C
Minimum service temperature	-150			°C
Thermal conductivity	15	–	21	W/m.°C
Specific heat capacity	450	–	470	J/kg.°C
Thermal expansion coefficient	12	–	13.5	µstrain/°C
Thermal shock resistance	196	–	245	°C
Thermal distortion resistance	1.17	–	1.66	MW/m
Latent heat of fusion	260	–	285	kJ/kg

AISI 329 Duplex, annealed, Stainless Steel Electrical properties

Electrical resistivity	70	–	90	µohm.cm
Electrical conductivity	1.92	–	2.46	%IACS
Galvanic potential	-0.25	–	-0.17	V

AISI 329 Duplex, annealed, Stainless Steel Magnetic properties

Magnetic type

Magnetic

AISI 329 Duplex, annealed, Stainless Steel Optical, aesthetic and acoustic properties

Transparency	Opaque
Acoustic velocity	4920	–	5120	m/s
Mechanical loss coefficient (tan delta)	6e-4	–	7.4e-4

AISI 329 Duplex, annealed, Stainless Steel Processing properties

Metal casting	Unsuitable
Metal cold forming	Acceptable
Metal hot forming	Acceptable
Metal press forming	Acceptable
Metal deep drawing	Limited use
Machining speed	25.6 m/min
Weldability Notes: Preheating and post weld heat treatments are not required	Good
Weldability – MIG	Good
Weldability – plasma	Good
Weldability – SAW	Good
Weldability – TIG	Good
Brazeability	Fair
Carbon equivalency	0.867 – 1.29

AISI 329 Duplex, annealed, Stainless Steel Durability

Water (fresh)	Excellent
Water (salt)	Excellent
Weak acids	Excellent
Strong acids	Acceptable
Weak alkalis	Excellent
Strong alkalis	Excellent
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 329 Duplex, annealed, Stainless Steel Corrosion resistance of metals

Pitting resistance equivalent number (PREN)	26.3 – 34.6
Pitting and crevice corrosion	High (30-40)
Stress corrosion cracking Note: Rated in chloride; Other susceptible environments: Hydrogen sulfide	Susceptible
Intergranular (weld line) corrosion	Excellent
Inorganic acids	Moderate
Organic acids	Good
Alkalis	Moderate
Humidity / water	Excellent
Sea water	Moderate
Sour oil and gas	Moderate

AISI 329 Duplex Stainless Steel Notes

The related type 329 duplex steel (USA UNS no. S32950) has been used successfully in nitric acid production, but only at temperatures below 260 C.

This is a first generation of duplex, no longer produced much.

AISI 329 Duplex Stainless Steel Standards with similar compositions

China: 0Cr26Ni5Mo2 to GB 1220, 0Cr26Ni5Mo2 to GB 13296, 0Cr26Ni5Mo2 to GB 4226, 0Cr26Ni5Mo2 to GB 4237, 0Cr26Ni5Mo2 to GB/T 14976, 0Cr26Ni5Mo2 to GB/T 3280, 0Cr26Ni5Mo2 to GB/T 4239, 0Cr26Ni5Mo2 to GB/T 6725

Japan: SUS329J1 to JIS G4303, SUS329J1 to JIS G4304, SUS329J1 to JIS G4305, SUS329J1 to JIS G4307, SUS329J1FB to JIS G4319, SUS329J1TB to JIS G3463, SUS329J1TP to JIS G3459, SUS329J1TPY to JIS G3468

South Korea: STS 329J1 to KS D 3706, STS329J1 to KS D 3692, STS329J1 to KS D 3698, STS329J1 to KS D 3705, STS329J1FB to KS D 3691, STS329J1TPY to KS D 3588

USA: 329 to ASTM A268/A268M, S32900 to ASTM A240/A240M, S32900 to ASTM A789/A789M, S32900 to ASTM A790/A790M, S32900 to ASTM A949/A949M, S32900 to ASTM A959, S32900 to SAE J405, UNS S32900