Alloy 28 Nickel Pipe

UNS N08028 / W.Nr. 1.4563

COMMON TRADE NAMES: Sanicro® 28, SAF® 28, Nic28, NiCro 31/27

Alloy 28 is a highly alloyed austenitic stainless steel intended for highly corrosive environments. It is resistant to strong acids, pitting corrosion, crevice corrosion, and stress corrosion cracking. Alloy 28 is commonly referred to by the tradename Sanicro® 28, 28 Chrome, and the universal designation of UNS N08028.

Characteristics

Corrosion Resistance

Alloy 28 has excellent resistance to strong acids, including phosphoric, hydrochloric, nitric, formic, and sulfuric acids. Its resistance to pitting and corrosion resistance makes it suitable for seawater piping and heat exchangers.

Elevated Temperature Resistance

Alloy 28 should not be exposed to temperatures exceeding 1100°F (593°C) for prolonged periods as this may result in embrittlement.

Mechanical Properties

In the annealed condition, Alloy 28 has a minimum yield strength of 32 ksi. However, it may also be provided in the cold-worked condition with yield strength exceeding 125 ksi. It maintains excellent toughness at cryogenic temperatures.

Heat Treatment

Alloy 28 cannot be strengthened by heat treating. Annealing is performed at 2000°F - 2100°F (1093°C - 1149°C), followed by rapid cooling.

Workability

Alloy 28 can be cold formed. However, it has a moderately 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 28 is used for heat exchangers in severely corrosive conditions high in chlorides, such as marine applications and oil and gas production. CRA offers specialty alloy 28 seamless pipe & tube for use in multiple industries and applications, including:

Oil & Gas
Chemical Processing
Marine
Nuclear

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Chemical Composition

C	Cr	Ni	Fe	Mn	Si	Mo	Cu	P	S
≤ 0.03	26 - 28	29.5 - 32.5	BAL	≤ 2.5	≤ 1	3 - 4	0.6 - 1.4	≤ 0.03	≤ 0.03

(mass %)

Specifications

ASTM B668, ASME SB668

Specified Mechanical Properties in Annealed Condition

Per ASTM B668

Tensile Strength	Yield Strength	Elongation
minimum, ksi	minimum, ksi	minimum, %
73	31	40

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

Typical Physical Properties

		70°F	200°F	400°F	600°F	800°F
Density	lbs/in³	0.29	-	-	-	-
Thermal Expansion	X10^-6/°F	-	8	8.5	9	9
Elastic Modulus	10³ ksi	28.3	27.6	26.3	25.1	23.8
Poisson Ratio	-	0.3	-	-	-	-
Thermal Conductivity	Btu-in/h·ft²·°F	66	84	102	114	132
Specific Heat	Btu/lb·°F	0.11	0.12	0.12	0.12	0.13
Yield Strength	ksi	31	28	23	22	19
Tensile Strength	ksi	73	74	64	57	53

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

Manufacturing 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 28 Schedule Pipe