28CR

28 Chrome

UNS N08028 / W.Nr 1.4563

COMMON TRADE NAMES: Alloy 28, 28Cr, Sanicro 28™, SAF 28®, VM® 28, Nic28, NiCro 31/27

28 Chrome, or Alloy 28, is a cold hardened 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 graphic

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.
Service Temperature

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

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.

Applications

28 Chrome is used in severely corrosive conditions high in chlorides, such as marine applications and oil and gas production. In upstream oil and gas, 28 Chrome’s increased resistance to the effects of H2S relative to stainless steels allows its use as downhole tubular components, packers, and other subsurface equipment in sour wells with high-pressure and high-temperature (HPHT) conditions and Acid Gas Injection (AGI) wells. CRA offers specialty alloy 28 Chrome seamless pipe & tube for use in multiple industries and applications, including:

  • As tubing, casing, and liners in oil and gas wells with high-pressure, high-temperature (HPHT) sour environments

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Chemical Composition

CCrNiFeMnSiMoCuPS
≤ 0.0326 - 2829.5 - 32.5BAL≤ 2.5≤ 13 - 40.6 - 1.4≤ 0.03≤ 0.03
(mass %)

Specified Mechanical Properties

API 5CRA / ISO 13680 Group 3 Category 27-31-4

GradeYield
Strength
ksi
Tensile
Strength
ksi
Elongation
%
Hardness
HRC
NACE MR0175/ISO 15156
H2S Sour Service Limits
minmaxminminmax
1101101401151133Table A.14
Type 4c
No limit ≤ 270°F,
Refer to table for temperatures up to 450°F
1251251501301035
140140160145938140 Grade not recommended for sour service
*Non-standard mechanical properties and grades are made available upon agreement.


Specified Mechanical Properties in Annealed Condition
Per ASTM B668
Tensile StrengthYield StrengthElongation
minimum, ksiminimum, ksiminimum, %
733140
*Higher strength properties can be provided in the cold hardened condition.

Typical Physical Properties

  70°F200°F400°F600°F800°F
Densitylbs/in30.29----
Thermal ExpansionX10-6/°F-88.599
Elastic Modulus103 ksi28.327.626.325.123.8
Poisson Ratio-0.3----
Thermal ConductivityBtu-in/h·ft2·°F6684102114132
Specific HeatBtu/lb·°F0.110.120.120.120.13
Yield Strengthksi3128232219
Tensile Strengthksi7374645753

Manufacturing Process

PROCESSDESCRIPTION
Steel MakingElectric Arc Furnace followed by Vacuum Oxygen Decarburization (VOD) or Argon Oxygen Decarburization (AOD).
Pipe MakingConventional Seamless Cold Finished Pipe and Tube Manufacturing Processes.
Heat TreatmentCannot be hardened by heat treatment. May be provided in the annealed or cold hardened condition.

Product Availability

MIN OD: 2-1/16″ (2.0625″)
MAX OD: 10-3/4″ (10.750”)
MAX WALL THICKNESS: 1.925”
LENGTHS: Up to 70′ (840”)

END FINISH: Plain end, Premium threads, & API threads

Standard & Non-Standard Sizes Available.

Manufactured Material Available as Quickly as 1 Week.

Non-Standard Mill Quantities Accommodated