Alloy 2205 Duplex Pipe

UNS S31803 / W.Nr. 1.4462

COMMON TRADE NAMES: Duplex, 22 Chrome, SAF® 2205

Alloy 2205 is a duplex stainless steel with a nitrogen addition for improved corrosion resistance, particularly where welding is required. In the annealed condition, alloy 2205 has more than twice the strength of conventional austenitic stainless steels and, in many environments, exhibits corrosion resistance superior to alloy 316. It is the most widely used of the duplex stainless steels. Alloy 2205 is commonly referred to as 22 Chrome and the universal designation of UNS N31803.

Characteristics

Corrosion Resistance

Alloy 2205 has excellent resistance to chloride-induced pitting corrosion and stress corrosion cracking. It has a minimum Pitting Resistance Number (PREN) of 35. It is suitable for service in environments high in chlorides, such as oil and gas production and in heat exchangers using chloride-bearing water as a coolant. It is also suitable for mild hydrogen sulfide, dilute reducing and organic acids, and moderate to high levels of oxidizing acids.

Elevated Temperature Resistance

The ASME Boiler and Pressure Vessel Code places an upper-temperature limit of 600°F (315°C). Exposure to temperatures above this for extended periods results in embrittlement.

Mechanical Properties

Alloy 2205 has more than twice the strength of conventional austenitic stainless steels in the annealed condition. It can also be provided in the cold-worked condition with yield strength exceeding 160 ksi. It maintains good toughness at temperatures down to -50°F (-10°C).

Heat Treatment

Alloy 2205 cannot be strengthened by heat treating. Annealing is performed at 1875°F - 2010°F (1024°C - 1099°C), followed by rapid cooling.

Workability

Alloy 2205 can be cold formed. However, it has a high work-hardening rate, so intermediate anneals may be required. Annealing is also recommended subsequent to hot forming or cold forming in order to achieve optimal stress corrosion resistance.

Applications

Alloy 2205 is used in environments high in chlorides such as marine applications, oil and gas production, and in heat exchangers using chloride-bearing water as a coolant. CRA offers specialty alloy 2205 seamless pipe & tube for use in multiple industries and applications, including:

High Chloride Environments
Oil & Gas
Marine
Chemical Processing
Desalination Plants

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Chemical Composition

C	Cr	Ni	Fe	Mn	Si	Mo	P	S	N
≤ 0.03	21 - 23	4.5 - 6.5	BAL	≤ 2	≤ 1	2.5 - 3.5	≤ 0.03	≤ 0.02	0.08 - 0.2

(mass %)

Specifications

ASTM A789, ASTM A790, ASME SA789, ASTM SA790

Specified Mechanical Properties

Per ASTM A789 / A790

Tensile Strength	Yield Strength	Elongation	Hardness
minimum, ksi	minimum, ksi	minimum, %	HRC
90	65	25	32

*Higher strength properties can be provided in the cold hardened condition.

Typical Physical Properties

		70°F	200°F	400°F	600°F
Density	lbs/in³	0.28	-	-	-
Thermal Expansion	X10^-6/°F	-	7.0	7.5	8.0
Elastic Modulus	10³ ksi	29.0	28.2	27.0	26.2
Poisson Ratio	-	0.3	-	-	-
Thermal Conductivity	Btu-in/h·ft²·°F	96	108	120	132
Specific Heat	Btu/lb·°F	0.11	.12	.13	.13
Yield Strength	ksi	65	30.2	26	23
Tensile Strength	ksi	90	75.2	66	64

Manufacturing Process

PROCESS	DESCRIPTION
Steel Making	Electric Arc Furnace followed by Vacuum Oxygen Decarburization (VOD) or Argon Oxygen Decarburization (AOD).
Pipe Making	Conventional Seamless Cold Finished Pipe and Tube Manufacturing Processes.
Heat Treatment	Cannot be hardened by heat treatment. May be provided in the annealed or cold hardened condition.

Schedule Pipe

Product Capabilities

CRA offers this alloy in:
Seamless Pipe

MIN OD: 2-1/16″ (2.0625″)
MAX OD: 10-3/4″ (10.750”)
THICKNESS: Up to 1.925”
LENGTHS: Up to 70′

Standard & Non-Standard Sizes Available.

Manufactured Material Available as Quickly as 1 Week.

Non-Standard Mill Quantities Accommodated

Alloy 2205 Schedule Pipe