Inconel 725 (UNS N07725)

Inconel 725 (UNS N07725) is a nickel-chromium-molybdenum-niobium alloy that is highly resistant to corrosion and has been age hardened for extremely high strength twice that of annealed alloy 625. Alloy 725 strength is developed by heat treatment rather than by cold work this also enables strength to be imparted to large non-uniform sections that cannot be strengthened by cold works.

Equivalent Grades

Trademark	GB	GOST	ASTM	UNS	DIN	W.Nr.	NF	BS	JIS	SS
Inconel 725	–	–	Inconel 725	N07725	–	–	–	–	–	–

Chemical Composition, %

Alloy

Inconel 725

≤0.03

≤0.20

≤0.35

≤0.015

≤0.010

19.0-22.5

55.0-59.0

7.0-9.5

2.75-4.00

≤0.35

1.0-1.7

Bal

Typical Physical and Mechanical Properties (RT, Annealed+Aged)

Density, g/cm3	Melting Point, ℃	Tensile Strength, MPa	Yield Strength, MPa	ELongation, %	Hardness, HRB
8.31	1271-1343	855	427	57	–

Available Products and Specifications

Rod, Bar, Wire and Forgings	ASTM B805
Plate, Sheet and Strip	–
Pipe and Tube	–
Welding Product	–
Others	–

Features

Inconel 725 is especially resistant to media containing carbon dioxide, chlorides, and hydrogen sulfide, such as those encountered in deep sour gas wells. In such environments, it resists general corrosion, pitting, sulfide stress cracking (hydrogen embrittlement), and stress-corrosion cracking. Inconel 725 also displays resistance to corrosion in brines and seawater.

Inconel 725 fills the need for greater environmental cracking resistance at high temperatures in deep, extremely hostile, oil and gas production environments. It offers better cracking resistance at elevated temperatures in higher levels of H2S due to the higher content of molybdenum.

Applications

Age-hardenable alloy 725 is used for hangers, landing nipples, side pocket mandrels, and polished bore receptacles in sour gas service. Also used for high-strength fasteners in marine applications. Its combined high strength and hardness make alloy 725 a suitable choice for polymer extrusion dies.