Alloy 625

Alloy 625 Nickel Pipe

UNS N06625 / W.Nr. 2.4856

COMMON TRADE NAMES: Inconel® 625, Sanicro® 625

Alloy 625 is a nickel-chromium-molybdenum solid solution strengthened alloy with a nominal chemical composition of 61% nickel, 22% chromium, and 9% molybdenum. It is commonly referred to by the tradename Inconel® 625 and the universal designation UNS N06625. Alloy 625 provides superior corrosion resistance in aggressive environments coupled with excellent strength and weldability.


Corrosion graphic

Corrosion Resistance

Alloy 625 has excellent corrosion resistance in a wide range of environments, including reducing and oxidizing acids, organic acids, salts, alkalis, and seawater. The high molybdenum content protects against pitting and other forms of localized corrosion.
Service Temperature

Elevated Temperature Resistance

The high chromium content in Alloy 625 provides excellent oxidation and scaling resistance at temperatures up to 1800°F (982°C). Additionally, alloy 625 exhibits superior resistance to recurrent heating/cooling cycles.
Mechanical Properties

Mechanical Properties

Alloy 625 is a solid solution alloy strengthened by additions of molybdenum and niobium. It can be provided in the annealed (Grade 1) condition, solution annealed (Grade 2) condition, or strengthened through the pilger process. Alloy 625 has excellent impact toughness at temperatures down to -320°F.
heat treatment logo

Heat Treatment

Alloy 625 isn’t typically strengthened by heat treatment. Solution annealing at 2000°F - 2200°F (1093°C - 1204°C) is commonly performed for applications above 1100°F to obtain optimal creep resistance. Annealing at 1600°F - 1900°F (871°C - 1037°C) is recommended for applications below 1100°F or to prevent sensitization during welding. To reduce residual stresses from fabrication, stress relieving is performed at 1100°F - 1500°F (600°C - 815°C). The rate of cooling after any of these processes does not affect mechanical properties.


Alloy 625 has good hot and cold workability in the annealed condition. Hot-working should be done above 1600°F (871°C) to ensure adequate ductility, while cold work is performed below 1200°F (649°C).


Alloy 625 is a versatile alloy used in many different applications, including the chemical process industry, aerospace, food processing, electronics, and nuclear power generation. Alloy 625 is used extensively to clad wetted surfaces of oil and gas equipment to protect against corrosion by H2S, CO2 , chlorides, and other aggressive media. Its elevated temperature oxidation resistance makes it a good choice for heat-treating fixtures, furnaces, incinerators, and other high-temperature equipment. CRA offers specialty alloy 625 seamless pipe & tube for use in multiple industries and applications, including:

  • Chemical Processing
  • Oil & Gas
  • Electronics
  • Nuclear Power Generation
  • Food Processing
  • Aerospace
  • High-temperature Environments
  • Heat-treating Fixtures
  • Furnaces
  • Incinerators
  • Condenser Tubes

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Chemical Composition

CCrNiFeMnSiMoCoPSTiNb + TaAl
≤ 0.120 - 23≥ 58≤ 5≤ 0.5≤ 0.58 - 10≤ 1*≤ 0.015≤ 0.015≤ 0.43.15 - 4.15≤ 0.4
(mass %)
*If determined


ASTM B444, ASME SB444, AMS 5581

Specified Mechanical Properties in Annealed (Gr. 1) or Solution Annealed (Gr. 2) Conditions

Per ASTM B444, ASME SB444, AMS 5581

ConditionTensile StrengthYield StrengthElongation
minimum, ksiminimum, ksiminimum, %
Grade 11206030
Grade 21004030
*Higher strength properties can be provided in the cold hardened condition.

Typical Physical & Mechanical Properties in Annealed Condition

Thermal ExpansionX10-6/°F-
Elastic Modulus103 ksi30.129.628.727.826.925.7
Poisson Ratio-0.2780.280.2860.290.295-
Thermal ConductivityBtu-in/h·ft2·°F68758798109139
Specific HeatBtu/lb·°F0.0980.1020.1090.1150.1220.118
Yield Strengthksi706863605934
Tensile Strengthksi14013413012912988

Manufacturing Process

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, solution annealed or cold hardened condition. The higher strength annealed condition is typically employed in services up to 1100°F, while the solution annealed condition is used in applications above 1100°F.

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