ThePipingMart Blog Grades 625 Haynes (UNS N06625) – Composition, Properties and Uses

625 Haynes (UNS N06625) – Composition, Properties and Uses

Haynes 625

UNS N06625 alloy is a nickel-chromium-molybdenum-tungsten superalloy developed for high-temperature applications requiring excellent corrosion and oxidation resistance. This alloy has excellent strength and toughness at temperatures up to 1500°F (816°C). It also offers superior thermal fatigue resistance, making it an ideal choice for aircraft components and other critical parts. In this blog, we’ll discuss the composition, mechanical properties, physical properties, uses, and corrosion resistance of Haynes 625 alloy.

625 Haynes Composition

The primary elements in Super Alloy HAYNES 625 (UNS N06625) are nickel (58%), chromium (21%), molybdenum (9%), tungsten (5.25%), and iron (4%). Minor amounts of manganese (1.50%), silicon (.30%), carbon (.20%), aluminium (.15%), and titanium (.10%) are also present.

Element Content (%)
Nickel, Ni 62
Chromium, Cr 21
Molybdenum, Mo 9
Iron, Fe ≤ 5
Tantalum, Ta 3.7
Niobium, Nb 3.7
Cobalt, Co ≤ 1
Manganese, Mn ≤ 0.50
Silicon, Si ≤ 0.50
Titanium, Ti ≤ 0.40
Aluminum, Al ≤ 0.40
Carbon, C ≤ 0.10

625 Haynes Mechanical Properties

Super Alloy HAYNES 625 exhibits excellent tensile strength and creep rupture strength at elevated temperatures. At room temperature, its yield strength is typically around 120 ksi, while its ultimate tensile strength ranges from 145 to 180 ksi depending on the condition of the material. Its elongation is typically around 30%, while its area reduction is usually about 40%.

Properties Metric Imperial
Tensile strength 915 MPa 133000 psi
Yield strength 425 MPa 61600 psi
Elastic modulus 208 GPa 30200 ksi
Elongation at break 46% 46%

625 Haynes Physical Properties

The density of Haynes 625 is 0.293 lb/in3 with an electrical resistivity of 860 mΩ-cm at 68 °F. Its thermal conductivity is 11 Btu/ft2/hr/ft/°F with a thermal expansion coefficient of 9 x 10–6 in./in./°F between 68 °F and 932 °F.

Properties Metric Imperial
Density 8.44 g/cm3 0.305 lb/in3
Melting point 1290 – 1350°C 2350 – 2460°F

625 Haynes Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@25-200°C/77-392°F) 12.8 µm/m°C 7.11 µin/in°F
Thermal conductivity 9.80 W/mK 68 BTU in/hr.ft².°F

625 Haynes Equivalent

AMS 5599 AMS 5837 AMS 5879 ASTM B443 ASTM B444
AMS 5581 AMS 5666 ASTM B366 ASTM B446 ASTM B704
ASTM B705 DIN 2.4856 GE B50TF133 MIL E-21562 (RN625)

625 Haynes Uses

625 Haynes alloy has been used in various industries, including aerospace for high-temperature turbine blades, combustors, afterburners, and exhaust systems; energy production for heat exchangers; chemical processing for heat exchangers; and marine applications such as valves and pumps.

Corrosion Resistance

This alloy 625 is highly resistant to oxidation at elevated temperatures due to its high chromium content, which forms a protective oxide layer on the surface when exposed to oxygen at temperatures over 1000°F (538°C). It is also resistant to carburization but can be susceptible to sulfidation if exposed to environments containing sulfur compounds or hydrocarbons containing sulfur compounds.


Haynes 625 is an incredibly versatile superalloy that can be used in many applications requiring good corrosion resistance at high temperatures, such as aerospace components, energy production equipment, chemical process equipment, valves & pumps in marine environments etc. It offers excellent mechanical properties such as high tensile strength & creep rupture strength even at elevated temperatures, along with good corrosion resistance due to its high chromium content, which forms a protective oxide layer on the surface when exposed to oxygen at temperatures over 1000 °F (538 °C). If you need an alloy with these properties, look no further than Haynes 625!

Related Post