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Inconel 625

Inconel 625

INCONEL® nickel-chromium alloy 625 (UNS N06625/W.Nr. 2.4856) is used for its high strength, excellent fabricability (including joining), and outstanding corrosion resistance. Service temperatures range from cryogenic to 1800°F (982°C). Strength of INCONEL alloy 625 is derived from the stiffening effect of molybdenum and niobium on its nickel-chromium matrix; thus precipitationhardening treatments are not required. This combination of elements also is responsible for superior resistance to a wide range of corrosive environments of unusual severity as well as to high-temperature effects such as oxidation and carburization.

Physical Properties

Density, lb/cu in……………0.305
Density, gram/cc……………8.44
Melting Range, °F……………………2350-2460
Melting Range,°C……………………1290-1350
Specific Heat, Btu/lb°F (J/kg°C)
Specific Heat0°F (-18°C)…………0.096 (402)
Specific Heat70°F (21°)…………..0.098 (410)
Specific Heat200°F (93°C)………0.102 (427)
Specific Heat400°F (204°C)…….0.109 (456)
Specific Heat600°F (316°C)……..0.115 (481)
Specific Heat,800°F (427°C)………0.122 (511)
Specific Heat,1000°F (538°C)…..…0.128 (536)
Specific Heat,1200°F (649°C)……..0.135 (565)
Specific Heat,1400°F (760°C)……..0.141 (590)
Specific Heat,1600°F (871°C)………0.148 (620)
Specific Heat,1800°F (982°C).…….0.154 (645)
Specific Heat,2000°F (1093°C)…….0.160 (670)
Permeability at 200 Oersted (15.9 kA/m)…………….1.0006
Curie Temperature, °F…………………..<-320
Curie Temperature,°C…………………..-196

Chemical Composition

Nickel………………………………58.0 min.
Chromium………………………..20.0-23.0
Iron………………………………….5.0 max.
Molybdenum…………………….8.0-10.0
Niobium (plus Tantalum)……3.15-4.15
Carbon………………………………0.10 max.
Manganese…………………………0.50 max.
Silicon……………………………….0.50 max.
Phosphorus………………………..0.015 max.
Sulfur…………………………………0.015 max.
Aluminum…………………………..0.40 max.
Titanium…………………………..…0.40 max.
Cobalta…………………………….….1.0 max.

Designation & Standards

INCONEL alloy is designated as UNS N06625, Werkstoff Number 2.4856 and ISO NW6625 and is listed in
NACE MR-01-75. It is available in all standard mill forms including rod, bar, wire, and wire rod, plate, sheet,
strip, shapes, tubular products, and forging stock. Full information on available products may be obtained from
the offices listed on the back cover.

Rod, Bar, Wire and Forging Stock: ASTM B 446/ASME SB 446 (Rod & Bar), ASTM B 564/ASME SB 564
(Forgings), SAE/AMS 5666 (Bar, Forgings, & Rings), SAE/AMS 5837 (Wire), ISO 9723 (Rod & Bar), ISO
9724 (Wire), ISO 9725 (Forgings), VdTÜV 499 (Rod & Bar), BS 3076NA21 (Rod & Bar), EN 10095 (Rod, Bar,
& Sections), DIN 17752 (Rod & Bar), ASME Code Case 1935 (Rod, Bar, & Forgings), DIN 17754 (forgings),
DIN 17753 (Wire).

Plate, Sheet and Strip :ASTM B 443/ASTM SB 443 (Plate, Sheet & Strip), SAE/AMS 5599 & 5869 & MAM
5599 (Plate, Sheet & Strip), ISO 6208 (Plate, Sheet & Strip), VdTÜV 499 (Plate, Sheet & Strip), BS 3072NA21
(Plate & Sheet), EN 10095 (Plate, Sheet & Strip), DIN 17750 (Plate, Sheet & Strip), ASME Code Case 1935.

Pipe and Tube:ASTM B 444/B 829 & ASME SB 444/SB 829 (Seamless Pipe & Tube), ASTM B704/B 751 &
ASME SB 704/SB 751 (Welded Tube), ASTM B705/B 775 & ASME SB 705/SB 775 (Welded Pipe), ISO 6207
(Tube), SAE/AMS 5581 (Seamless & Welded Tube), VdTÜV 499 (Tube), BS 3074NA21 (Seamless Pipe &
Tube), DIN 17751 (Tube), ASME Code Case 1935.

Other Products –ASTM B 366/ASME SB 366 (Fittings), ISO 4955A (Heat Resisting Steels & Alloys),
DIN 17744 (Chemical composition of all product forms).

Applications

The soft annealed version of  Alloy 625 (grade 1) is used in the oil and gas industry, the chemical process industry,
marine engineering and environmental engineering. Typical applications include:

  • Equipment for the production of super phosphoric acid.
  • Plants for the treatment of radioactive waste.
  • Production pipe systems and linings of risers in oil production.
  • Offshore industry and seawater exposed equipment.
  • Sea water piping in shipbuilding.
  • Stress corrosion cracking resistant compensators.
  • Furnace linings.

The solution annealed variant of  Alloy 625 (grade 2) is used for high temperature applications up to 1,000 °C (1,832 °F), acc. to ASME Code for Pressure Vessels. Typical applications include:

  •  Flaring systems in refineries and offshore platforms.
  •  Recuperators and compensators for hot exhaust gases. FM 625 is used as a matching filler metal for corrosion-resistant coatings of less resistant steels (overlay welding).

Typical applications include:

  • Components in the oil and gas extraction.
  • Superheater tubes in waste incineration plants