Inconel 625 Pipes and Tubes

Inconel 625 Pipes and Tubes

The Inconel 625 tube and pipes are made with a nickel-based superalloy that has resistance to higher temperatures and better strength properties. Inconel 625 pipe and tube have remarkable protection against corrosion and oxidation.

The superalloy 625 with which the Inconel 625 pipe and tubes are made enable them to fight against a wide variety of severe corrosive environments. Inconel 625 pipe fittings (UNS N06625) resist a wide range of severely corrosive environments and are especially resistant to corrosion against pitting and crevice environments.

GRADE   Cr Mo Co Nb+Ta Al Ti C Fe Mn Si P S Ni
INCONEL 625 MIN % 20 8 3.15 Balance
MAX % 30 10 1 4.15 0.4 0.4 0.1 5 0.5 0.5 0.015 0.015

Production Process

Inconel 625 tubes and pipes or UNS N06025 come in different forms like round, square, rectangle, etc., and are manufactures with methods like ERW ( Electric Resistance Welded), Seamless, and EFW ( Electric Fusion Welding). The Inconel 625 tube sizes vary and have specific ends such as plain end, bevel end, and threaded end with a regular thickness of different schedule ranging from SCH 5 to SCH XXS.


Grade Density Thermal Elastic Specific Electrical
Inconel 625 (g/cm3) Conductivity Modulus Heat Resistivity
  W.m -1.°K-1 (GPa)°K-1 (μΩ.cm)
8.42 1354-1413 207 460 10.3

The processes used to manufacture Inconel 625 tube and pipes are cold pilgering process, extrusion process, tube mill process, and piercing process which need to be followed by heat treatment and mechanical testing.


Inconel 625  Seamless Pipe : ASTM/ASME B 444 / SB 444

Inconel 625 Seamless tube : ASTM/ASME B 444 / SB 444

Inconel 625 ERW Pipe         : ASTM/ASME B 705/ SB 705

Inconel 625 ERW Tube        : ASTM/ASME B 704/ SB 704

Fabrication and Heat treatment

Alloy 625 can be produced with various cold and hot working processes. These processes resist deformation at hot working temperatures; thus higher loads are needed to form the material. Hot forming should be worked within a temperature range of 1700° F to 2150°F. While cold working, the Inconel 625 material hardens faster than traditional austenitic stainless steel.


    BS EN        
INCONEL 625 N06625 NA 21 2.4856 XH60BT ЭИ602 NC22DNB4M NCF 625

The Inconel 625 tube and pipes need to be annealed at about 2200°F and air quench or quicker. Alloy Inconel 625 is ductile and strong at lowered temperatures. The Inconel 625 pipe fittings have high strength, fatigue and thermal-fatigue strength, greater resistance to oxidation, and better weldability and brazeability, thus Inconel 625 is used in various industries. 


Alloy 625 pipe and tubes are resistant to oxidation and scaling at higher temperatures. At 1800°F, scaling resistance becomes a crucial factor in working conditions. It is better than other high-temperature alloys when exposed to cyclic heating and cooling conditions. The content of the alloying elements in the Inconel 625 pipe makes it withstand various severe corrosive environments.

Mechanical Properties

GRADE Tensile Strength Yield Strength Elongation
  [MPA] [MPA] (% in 50mm) min
Inconel 625 GRADE-1 827 414 30
Inconel 625 GRADE-2 690 276 30

The content of molybdenum also provides pitting and crevice resistance and niobium stabilize the Inconel 625 tube and pipes during welding against sensitization, thus preventing further intergranular cracking. Also, the high nickel content makes it strong against chloride ion stress corrosion cracking.

Although Inconel 625 tube sizes are different, one thing that remains constant is the resistance in the corrosive environments due to a combination of nickel and chromium. This combination also provides resistance to oxidizing chemicals, and the high nickel and molybdenum contents supply resistance to nonoxidizing environments.


Inconel 625 pipe and tubes due to their high corrosive nature mostly used in heat exchangers, marine applications, nuclear reactor, oil and gas industry, chemical applications, and many others.

  • Aircraft ducting systems
  • Jet engine exhaust systems
  • Engine thrust-reverser systems
  • Specialized seawater equipment
  • Chemical process equipment

NOTE: Inconel 625 Pipes and Tubes is a registered trademark of  Special Metals Corporation.