AISI 446 Stainless Steel Material Data Sheet (Ferritic, Annealed)

AISI 446 Designation

AISI 446, wrought
Condition	Annealed or annealed and cold or hot finished
UNS number	S44600
US name	ASME 446, ~ASTM WP446, ~ASTM S44600, ~ASTM MT446-2, ~ASTM MT446-1
EN name	X18CrN28
EN number	1.4749
ISO name	~X15CrN26
JIS (Japanese) name	~SUH446

AISI 446 Typical uses

Piping and heat exchanger tubings, 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 446 Composition details

C (carbon)	0	–	0.2	%
Cr (chromium)	23	–	27	%
Fe (iron)	69.2	–	77	%
Mn (manganese)	0	–	1.5	%
N (nitrogen)	0	–	0.25	%
Ni (nickel)	0	–	0.75	%
P (phosphorus)	0	–	0.04	%
S (sulfur)	0	–	0.03	%
Si (silicon)	0	–	1	%

AISI 446 Physical properties

Density

7.4

–

7.6

g/cm3

AISI 446 Mechanical properties

Young’s modulus	195	–		205		GPa
Specific stiffness	25.9	–		27.4		MN.m/kg
Yield strength (elastic limit)	275	–		350		MPa
Tensile strength	480	–		615		MPa
Specific strength	36.6	–		46.7		kN.m/kg
Elongation	13	–		20		% strain
Compressive strength	275	–		350		MPa
Flexural modulus	195	–		205		GPa
Flexural strength (modulus of rupture)	275	–		350		MPa
Shear modulus	75	–		81		GPa
Bulk modulus	144	–		159		GPa
Poisson’s ratio	0.275	–		0.285
Shape factor	59
Hardness – Vickers	190	–		225		HV
Hardness – Rockwell B	79	–		89		HRB
Hardness – Rockwell C	8	–		17		HRC
Hardness – Brinell	157	–		210		HB
Elastic stored energy (springs)	191	–		303		kJ/m3
Fatigue strength at 10^7 cycles	243	–		269		MPa
Fatigue strength model (stress range) Parameters: Stress Ratio = -1, Number of Cycles = 1e7cycles			201		–		325	MPa

AISI 446 Impact & fracture properties

Fracture toughness	72	–	122	MPa.m0.5
Toughness (G)	27.4	–	70.5	kJ/m2

AISI 446 Thermal properties

Melting point	1430	–	1510	°C
Maximum service temperature	1080	–	1180	°C
Minimum service temperature	-73	–	-43	°C
Thermal conductivity	19	–	23	W/m.°C
Specific heat capacity	480	–	520	J/kg.°C
Thermal expansion coefficient	9	–	11	µstrain/°C
Thermal shock resistance	134	–	182	°C
Thermal distortion resistance	1.83	–	2.41	MW/m
Latent heat of fusion	260	–	285	kJ/kg

AISI 446 Electrical properties

Electrical resistivity	62	–	72	µohm.cm
Electrical conductivity	2.39	–	2.78	%IACS
Galvanic potential	-0.26	–	-0.18	V

AISI 446 Magnetic properties

Magnetic type	Magnetic
Coercive force Hc	358 A/m
Maximum permeability	1000

AISI 446 Magnetic properties information                                                                                

Used as soft magnetic components in products such as solenoid housings, cores, and pole pieces. Although their magnetic properties are not generally as good as conventional soft magnetic alloys, they have been successfully used for magnetic components that must withstand corrosive environments. As such, they offer a cost-effective alternative to plated iron and silicon-iron components. In addition, the relatively high electrical resistivity of ferritic stainless steels has resulted in superior ac performance.

AISI 446 Optical, aesthetic and acoustic properties

Transparency	Opaque
Acoustic velocity	5090	–	5240	m/s
Mechanical loss coefficient (tan delta)	9e-4	–	0.00116

AISI 446 Processing properties

Metal casting	Unsuitable
Metal cold forming	Limited use
Metal hot forming	Acceptable
Metal press forming	Limited use
Metal deep drawing	Limited use
Machining speed	26.8 m/min
Weldability Notes: Preheating and post weld heat treatment are not required	Good
Weldability – MIG	Good
Weldability – plasma	Good
Weldability – SAW	Not recommended
Weldability – TIG	Good
Brazeability	Fair
Carbon equivalency	0.767 – 1.2

AISI 446 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 446 Corrosion resistance

Pitting resistance equivalent number (PREN)	23 – 31
Pitting and crevice corrosion	Medium (20-30)
Stress corrosion cracking Note: Rated in chloride; Other susceptible environments: Hydrogen sulfide	Not susceptible
Intergranular (weld line) corrosion	Good
Inorganic acids	Restricted
Organic acids	Restricted
Alkalis	Moderate
Humidity / water	Excellent
Sea water	Good
Sour oil and gas	Restricted

AISI 446 Notes

Warning for AISI 446

When used with nitric acid, failures due to crevice corrosion have been experienced.

AISI 446 Standards with similar compositions

Canada: 446 to CSA G110.3, 446 to CSA G110.5

China: 2Cr25N to GB 4238

Hungary: H17 to MSZ 4359

India: X15Cr25N to IS 1570/5

International: X15CrN26 to ISO 16143-3, X15CrN26 to ISO 4955

Italy: X16Cr26 to UNI 6901, X16Cr26 to UNI 6904

Japan: SUH446 to JIS G4309, SUH446 to JIS G4311, SUH446 to JIS G4312

Mexico: 446 to NMX-B-83, MT446-1 to NMX-B-171, MT446-2 to NMX-B-171

Russia: 15KH25T to GOST 5632

South Korea: STH 446-W2 to KS D 3703, STR 446 to KS D 3731, STR 446 to KS D 3732

USA: 446 to ASTM A176-99, 446 to ASTM A473, 446 to FED QQ-S-763F, 446 to FED QQ-S-766D, 446 to MIL-S-862B, MT446-1 to ASTM A511, MT446-2 to ASTM A511, S44600 to ASTM A276, S44600 to ASTM A314-97, S44600 to ASTM A580/A580M-98, S44600 to ASTM A959, TP446-1 to ASTM A268/A268M, TP446-2 to ASTM A268/A268M, UNS S44600, WP446 to ASTM A815/A815M

Tradenames: ALLEGHENY LUDLUM TYPE 446