What Grade of Stainless Steel Is 1.4462?

1.4462 is the EN material number of X2CrNiMoN22-5-3, the standard 22% chromium duplex stainless steel. In American practice the same alloy is known as UNS S31803 and, in its optimized composition with tighter chromium, molybdenum and nitrogen control, as UNS S32205; forged bars and fittings are commonly ordered to ASTM A182 as F51 or F60. Duplex describes the microstructure: roughly equal parts ferrite and austenite, which combine the strength of ferritic steel with the toughness and corrosion resistance of austenitic steel.

Designations and Equivalents

System	Designation
EN (Europe)	1.4462, X2CrNiMoN22-5-3
UNS (USA)	S31803 / S32205
ASTM A182 (forged bar and fittings)	F51 / F60
Common name	Duplex 2205 (22% Cr duplex)

The optimized UNS S32205 composition is the one most often specified today, because its tighter ranges guarantee the pitting resistance expected of the grade.

Chemical Composition

Element	% Present
Carbon (C), max	0.03
Silicon (Si), max	1.00
Manganese (Mn), max	2.00
Phosphorus (P), max	0.030
Sulfur (S), max	0.020
Chromium (Cr)	21.00-23.00
Nickel (Ni)	4.50-6.50
Molybdenum (Mo)	2.50-3.50
Nitrogen (N)	0.10-0.22
Iron (Fe)	Balance

Nitrogen is an essential alloying element: it stabilizes austenite and raises the pitting resistance equivalent number (PREN) of the 2205 class into the range of about 34-36.

Mechanical and Physical Properties

The mechanical values below are specified in EN 10088-3 for solution-annealed bar and sections with diameter or thickness up to 160 mm.

Property	Value
0.2% proof strength, min	450 MPa
Tensile strength	650-880 MPa
Elongation, min	25%
Impact energy KV2, min	100 J
Hardness, max	270 HBW
Resistance to intergranular corrosion	Yes

Physical property	Value
Density	7.805 g/cm3
Mean coefficient of thermal expansion	13.7 x 10-6 /K
Modulus of elasticity	200 GPa
Thermal conductivity	19.0 W/(m.K)
Electrical resistivity	0.85 x 10-6 ohm.m

These strength values are nearly double the proof strength of 304 or 316, which allows section reduction in structural and pressure-retaining applications.

Corrosion and Heat Resistance

The high chromium and molybdenum content gives 1.4462 excellent resistance to pitting and intergranular corrosion, and the duplex microstructure is notably resistant to chloride stress corrosion cracking, the failure mode that limits austenitic 304 and 316 in hot chloride and sulfide service. The grade has limits: above roughly 300 C, the chromium-rich ferrite can embrittle, so 1.4462 is not a high-temperature alloy. At low temperature, duplex steels retain ductility better than ferritic or martensitic grades and can be used down to at least -50 C.

Magnetic Behavior and Typical Applications

Unlike 304 or 316, 1.4462 is magnetic, because the ferrite phase is ferromagnetic. This is a normal characteristic of the grade and is sometimes used as a quick identification check. Typical applications include chemical process plant, oil and gas exploration, production and refining equipment, offshore platforms, marine components, pulp and paper plant, and pollution control equipment such as flue gas desulfurization systems.

FAQ

Q1: What grade of stainless steel is 1.4462?

A: It is X2CrNiMoN22-5-3, the standard 22% chromium duplex stainless steel, equivalent to UNS S31803 or S32205 and to ASTM A182 F51 or F60.

Q2: Is 1.4462 stainless steel magnetic?

A: Yes. The mixed ferritic-austenitic microstructure contains a significant ferromagnetic ferrite phase, unlike non-magnetic austenitic 304 or 316.

Q3: What is the difference between 1.4462 and 1.4410?

A: 1.4410 is a super duplex grade (X2CrNiMoN25-7-4) with higher chromium, nickel, molybdenum and nitrogen, giving higher strength and pitting resistance for the most demanding offshore and chemical service.

Q4: What are the mechanical properties of 1.4462?

A: Per EN 10088-3, a 0.2% proof strength of at least 450 MPa, tensile strength of 650-880 MPa, elongation of at least 25%, impact energy of at least 100 J and hardness up to 270 HBW.

Q5: Where is 1.4462 used?

A: Chemical processing and storage, oil and gas exploration and refining, offshore and marine equipment, pulp and paper, and pollution control systems.

Q6: Can 1.4462 be used at high temperature?

A: No. Above about 300 C the ferrite phase can embrittle, so duplex grades are selected for strength and corrosion resistance at moderate temperatures, not for high-temperature service.