Alloy 625

A nickel-chromium-molybdenum-niobium grade, Alloy 625 offers outstanding corrosion resistance and weldability.

Alloy 625 supplied in the annealed condition provides good fatigue strength and resistance to chloride-ion stress corrosion cracking. Typical applications being sea-water and other harsh chemical environments where high mechanical stresses apply.

Alloy 625 is particularly useful in situations where oxidation resistance and avoidance of pitting is required.

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  • ASTM B446-03 Grade 1,
  • ASTM B564, BS3076-01
  • UNS N06625 GRADE 1/DIN 2.4856
  • AMS 5666 REV J BS3076 1989 NA21
  • NACE MR0175 (ISO 15156-3, latest revision)

About Alloy 625

Alloy 625 is a nickel-chromium alloy which has superior resistance to a wide range of corrosive environments as well as the high temperature effects of oxidation and carburisation.

Alloy 625 is excellent for sub-sea applications, having excellent pitting and corrosion properties, high corrosion fatigue strength and resistance to chloride-ion stress corrosion cracking. This alloy also demonstrates high strength properties, high tensile, creep and rupture strength, fatigue and thermal fatigue strength and oxidation resistance, making it suitable for many aerospace applications such as aircraft engine exhaust systems, housing engine controls and aircraft ducting systems. This alloy is also used in the nuclear field applications such as control rod components and heat exchanger tubing. Alloy 625 is also the alloy of choice for weld overlay applications in the oil and gas/petrochemical and refineries markets.

  • Oil and Gas - commonly used for valve bodies, valve components, many marine applications
  • Aerospace - commonly used for aircraft engines, exhaust systems, ducting systems, more
Technical data
Chemical analysis
0.10 Max
0.50 Max
0.50 Max
0.40 Max
0.40 Max
20.0 Min - 23.0 Max
8.0 Min. - 10.0 Max.
58.0 Min.
0.015 Max
0.015 Max
1.0 Max
Niobium (Columbium) + Tantalum
3.15 Min. - 4.15 Max.
5.0 Max
Physical properties
Heat Treatment
Anneal at 875 – 1038°C for 30 minutes to 4 hours maximum at the set point temperature followed by quenching in water.
Size range
Bar stock: 12.7mm to 300mm Dia
Ingot: 300mm to 610mm Dia
Mechanical properties
Yield 0.2% Offset
60 000 psi Min. (414 MPa)
120 000 psi Min. (828 MPa)
Reduction of Area
35% Min.
30% Min.
35HRC Max
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