Nickel alloy Inconel 725 is a nickel-chromium-molybdenum-niobium alloy that is highly resistant to corrosion and is age-hardenable for extremely high strength. The strength of this alloy is developed by heat treatment to achieve high ductility and toughness. The alloy is resistant to hydrogen embrittlement and stress-corrosion cracking.
Applications of Inconel 725:
The alloy is used for hangers, landing nipples, side pocket mandrels, and polished bore receptacles in sour gas service.
It resists the effects of hydrogen sulfide, chlorides, and carbon dioxide.
The alloy is also attractive for high-strength fasteners in marine applications, where it resists corrosion, pitting, and crevice attack in seawater.
Normal product forms: bars and wires.
Specifications/Standard: ASTM B805, NACE MR0175 / ISO 15156, API 6ACRA
Chemical Composition:
Nickel (Ni): 55.0-59.0%
Chromium (Cr): 19.0-22.5%
Molybdenum (Mo): 7.0-9.5%
Niobium (Nb): 2.75-4.0%
Titanium (Ti): 1.0-1.7%
Aluminum (Al): 0.35 max.
Carbon (C): 0.03 max.
Manganese (Mn): 0.35 max.
Silicon (Si): 0.20 max.
Phosphorus (P): 0.015 max.
Sulfur (S): 0.010 max.
Iron (Fe): Balance
Physical Constants and Thermal Properties
Density: 0.30 Ib/in³, 8.3 g/cm³
Melting point: 2320 – 2449℉, 1271-1343ºC
Thermal expansion co-efficient (at 21-100°C): 13 µm/m°C
