• BS 3076 NA21
  • 2.4856
  • ASTM B564
  • ASTM B466
  • UNS N06625
  • Nace MR01-75 / ISO 15156
  • ASME B466
View Data Tables For This Product

Alloy 625 (UNS N06625)

Alloy 625, often referred to as Inconel 625 (where Inconel is a trademark of Special Metals Corp) is a nickel-chromium-molybdenum-niobium alloy (NiCr22Mo9Nb), supplied in the hot worked and annealed condition. Perfectly suited to the most demanding applications, it achieves high-strength levels from the solid solution effects of Molybdenum and Niobium (Colombium) from room temperature up to 800°C.

It is particularly useful in situations where oxidation resistance and avoidance of pitting is required. In the annealed condition, it is fully austenitic and is suitable for machining. It provides excellent corrosion resistance in a wide variety of severe corrosive environments due to its high alloy content. With nearly 60% nickel composition it is virtually immune from stress corrosion cracking.

Alloy 625 is non-magnetic and able to operate over a wide temperature range, from cryogenic temperatures up to 980degC. This supports applications in jet engines, heat exchangers, furnace hardware and chemical plant equipment.

Langley Alloys can supply this product in a variety of different industry specifications. It is primarily offered as ASTM B446 for applications within the chemical process and Oil and Gas industries. The most common specification is Alloy 625 Grade 1, although Langley Alloys are also able to offer Alloy 625 Grade 2 when required. For aerospace-related applications, we can also provide Alloy 625 in compliance with SAE AMS 5666.

Langley Alloys carries an extensive stock of Alloy 625 from 0.5″ (12.7mm) to 10″ (254mm) diameter solid bars that meets ASTM B446 Grade 1 and Grade 2 plus SAE AMS 5666 requirements.

stainless steels


  • BS 3076 NA21
  • 2.4856
  • ASTM B564
  • ASTM B466
  • UNS N06625
  • Nace MR01-75 / ISO 15156
  • ASME B466
View Data Tables For This Product

Data Tables

Chemical Composition:


Mechanical Properties:

Bars up to and including 4” diameter or sectionBars above 4” diameter or section
0.2% Proof Stress415 N/mm260ksi345 N/mm250ksi
Tensile Strength830 N/mm2120ksi760 N/mm2110ksi
Elongation, 5.65√S0 and 4D30%25%
Reduction of Area35%35%
Hardness (Brinell)


  1. Tensile testing shall be carried out in accordance with ASTM A370 or EN10002-1
  2. Minimum properties quoted (tested at room temperature in a longitudinal direction)
  3. Testing performed on each melt of material per heat treatment batch

Physical Properties:

Density (Kg.m-1)84.4
Magnetic Permeability (20°C)<1.001
Curie Temperature (°C)-196
Young’s Modulus (N/mm2)207.5
Specific Heat, 20°C (J/(g.K))410
Specific Electrical Resistance, 20°C (Ω-m)0.0129
Thermal conductivity, 20°C (W/(m.K))9.9
Mean coefficient of thermal expansion, 20-100°C (/K)12.8 x 10-6

Product Features

Key Features:

  • Good strength/ductility properties from sub-zero temperatures to over 980°C
  • Excellent corrosion and fatigue resistance in a wide variety of corrosive environments including seawater and industrial acids
  • Non-magnetic and spark resistant
  • Resistant to high temperature oxidation and carburisation
  • Excellent resistance to stress corrosion cracking


  • Wellhead components
  • Sheathing, Fasteners, Clamps
  • Downhole equipment for corrosive/sour service
  • Propellers and Shafts
  • Propulsion Motors
  • Fasteners
  • Reactor core & control rod components
  • Chemical process equipment
Datasheet NA Alloy 625
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