Alloy 625 is a nonmagnetic, corrosion and oxidation-resistant, nickel-based alloy. Its outstanding strength and toughness in the temperature range cryogenic to 2000°F (1093°C) are derived primarily from the solid solution effects of the refractory metals, columbium and molybdenum, in a nickel-chromium matrix. The alloy has excellent fatigue strength and stress-corrosion cracking resistance to chloride ions. Some typical applications for alloy 625 have included heat shields, furnace hardware, gas turbine engine ducting, combustion liners and spray bars, chemical plant hardware, and special seawater applications.
· Aircraft ducting systems
· Jet engine exhaust systems
· Engine thrust-reverser systems
· Specialized seawater equipment
· Chemical process equipment
Density (lb / cu. in.)
Specific Heat (Btu/lb/Deg F - [32-212 Deg F])
Melting Point (Deg F)
Mean Coeff Thermal Expansion
Modulus of Elasticity Tension
Reduction of Area
.2% Yield ksi(MPa)
Rod & Bar
Tube & Pipe
Tube & Pipe
Alloy 625 has three basic heat treatments:
(1)High Solution Anneal - 2000/2200°F (1093/1204°C), air quench or faster.
(2)Low Solution Anneal - 1700/1900°F (927/1038°C), air quench or faster.
(3)Stress Relieve - 1650°F (899°C), air quench.
Hot working may done at 2100°F (1149°C) maximum furnace temperature. Care should be exercised to avoid frictional heat build-up which can result in overheating, exceeding 2100°F (1149°C). Alloy 625 becomes very stiff at temperatures below 1850°F (1010°C). Work pieces that fall below this temperature should be reheated. Uniform reductions are recommended to avoid the formation of a duplex grain structure. Approximately 15/20% reduction is recommended for finishing.
Alloy 625 can be cold formed by standards methods. When the material becomes too stiff from cold working, ductility can be restored by process anneal.
Low cutting speeds, rigid tools and work piece, heavy equipment, ample coolant and positive feeds are general recommendations.