28 Chrome

Also Known As

• Alloy 28
• 28Cr
• Sanicro 28™
• SAF 28®
• VM® 28
• Nic28
• NiCro 31/27
• W. Nr. 1.4563

Suitable Applications

High-pressure, high-temperature (HPHT) sour environments

Product Availability

FORMS:
Seamless Pipe, Tubing

OD:
MIN OD: 2-7/8”
MAX OD: 10-3/4”
Standard & Non-Standard Sizes Available

RANGE:
R1, R2, R3, Lengths up to 70'

28 Chrome

UNS N08028 | Datasheet

28CR Applicable Environments28 Chrome (UNS N08028), or Alloy 28, is a cold hardened nickel-based alloy intended for corrosion resistance in highly sour (H2S) environments with moderate chloride content, requiring high strength up to 350°F.

28 Chrome offers increased resistance to the effects of H2S relative to stainless steels allowing 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. In addition, it has a high resistance to pitting and crevice corrosion in the presence of chlorides. However, all environmental factors, including H2S, CO2 , temperature, pH, and chloride concentration, should be considered before final material selection.

The alloy is classified in MR0175/ISO15156 as a type 4c alloy, with no restrictions to a partial pressure of H2S below 270°F and resistant to 200 psi H2S at 350°F.

Chemical Composition

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

Manufacturing Process

PROCESSDESCRIPTION
Steel MakingMade by electric furnace process or blast furnace followed by Vacuum Oxygen Decarburization (VOD) process or Argon Oxygen Decarburization (AOD) Process
Pipe MakingManufactured by traditional tube manufacturing processes, High strength tubulars should be furnished in cold worked condition
Heat TreatmentSolution Annealing Process before final cold drawing

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.

Typical Physical Properties

  70°F200°F400°F
Densitylbs/in30.29
Thermal ExpansionX10-6/°F888.5
Elastic Moduluspsi x 10628.327.626.3
Poisson Ratio0.3
Thermal ConductivityBtu/ft h °F5.578.5
Specific HeatBtu/lb °F0.110.120.12

    Get Your Project Started, Speak to the CRA Team.