Inconel 725 is kind of high strengh and high temperature alloy material which has high yield strength and durability. It has the character of good weldability, excellent corrosion resistance, high temperature and oxidation resistance and excellent comprehensive performance.
Inconel 725 has substantially the same corrosion resistance as the Inconel 625, which is widely used in a wide range of severe corrosive environments. The strength of the age-hardened Inconel 725 alloy is twice that of the annealed alloy 625. Because the strength of 725 alloy is generated by heat treatment rather than cold working, the ductility and toughness remain high. In addition, strength can be given to large or uneven parts that cannot be strengthened by cold working.
High nickel and chromium content provides corrosion resistance in both reducing and oxidizing environments. Large molybdenum content enhances resistance to reducing media and provides a high degree of resistance to pitting and crevice corrosion. In addition, the combination of elements makes the alloy resistant to hydrogen embrittlement and stress corrosion cracking.
The properties of Inconel 725 alloy are suitable for a range of applications requiring excellent corrosion resistance and high strength. The alloy is used in acid gas service for hangers, landing joints, side pocket mandrels and polished hole containers that are resistant to the effects of hydrogen sulfide, chloride and carbon dioxide. The alloy is also attractive for high-strength fasteners in Marine applications because it resists corrosion, pitting and crevice erosion in seawater.
Inconel 725 Chemical Composition
Inconel 725 Physical Properties
Inconel 725 Mechanical Properties
|Ultimate Tensile Strength /Mpa *||1254||1230||1189||1170||1099||1096||1106||1058||-||-|
|0.2% Yield Strength /Mpa *||892||868||826||824||782||798||818||778||-||-|
|Reduction of area % *||48.4||47||50.2||52.4||54.2||53.4||49.6||47.7||-||-|
|Elongation % *||32||29.6||30.9||30.7||32.4||30.8||29.6||31||-||-|
|Coefficient of Thermal Expansion /µm/m°C||-||13||-||13.1||13.4||13.7||-||14.1||14.4||-|
|Thermal Conductivity /kcal/(hr.m.°C)||9.143||10.082||10.89||11.709||13.235||14.058||14.864||16.22||18.24||21.57|
|Modulus of Elasticity / GPa||204||200||-||194||188||182||-||177||169||-|
Phase characteristics of Inconel 725
The results show that the main strengthening mechanism of Inconel 725 alloy is the precipitation of γ ‘/γ “phase and fine crystal strengthening. The strength of the alloy is mainly determined by the number of γ ‘/γ “phases and particle spacing. The smaller the spacing, the greater the intensity. The plasticity of the alloy is mainly determined by the amount of δ phase precipitation, which is not conducive to the improvement of plasticity. In addition, the number of δ phase is also closely related to the grain size, and its pinning effect on the grain is not conducive to the growth of the grain. δ phase rarely precipitates at grain boundaries in the form of particles after solution at 996℃ for 1.5h, and completely dissolves in the matrix after solution at 1040℃ for 1h. The precipitation of δ phase can be reduced effectively by appropriate heat treatment process.
Inconel 725 is resistant to corrosion pitting
The pitting corrosion of Inconel 725 and Inconel 718 alloys originated from the precipitated MC carbides. Temperature has little effect on the pitting of Inconel 725 alloy, and the critical pitting temperature is up to 90±3℃. The hydrogen embrittlement resistance of Inconel 718 alloy is better than that of Inconel 725 alloy. The strength loss rate caused by hydrogen embrittlement is 27% and 31.6%, respectively.
The optimum processing temperature of Inconel 725 alloy ranges from 1100℃ to 1150℃, strain rate ranges from 0.1 to 1s-1, and activation energy of hot deformation is 240.34 kJ/mol.
- Bars & Rods & Foring Ring /Flanges
- Sheet & Plate
- Strip & Coil
- Welding Wire &Spring wire
- Seamless Tube & Welded Pipe
»Round Bar & Square Bar & Hexagon Bar
● Diameter : φ8～φ300mm Length:10mm-6000mm
● Hot forging, Hot Rolling, Cold Drawing
● Bright Surface, Polished Surface, Black Surface
»Tube & Pipe:Seamless Tube& Welded Pipe
● Cold Drawing Seamless Pipe： φ1.0～φ220mm
● Hot Extrusion pipe: φ50～φ250mm
● Others : U Blend Tube and Elbow
»Hot Rolled Plate & Cold Rolled Sheet
● Cold Rolling Sheet Thickness: ≦2.0mm Width:≦1500m
● Hot rolling Plate Thickness: ≧4.0mm Width: ≦2500m
»Strip & Tape Ribbon
● Thickness: ≧ 0.01mm Width: 15mm-300mm
● Cold rolling BA Strip, Hard & Soft Condition
»Straight Length Wire & Spool Wire
● Welding Wire: φ 0.1mm～6.0mm Cut length Rod: φ1.0～φ8.0mm
● Package : 5-25kg/Spool or Box
Alloy 725 Applications
Alloy 725 is primarily used in the chemical industry, especially in acidic environments under high temperature and pressure. It can be used to manufacture chemical reactor, hydrogenation reactor, steam generator, air preheater, heat exchanger and other equipment. Alloy 725 is used in offshore engineering to build subsea oil and gas production pipelines and offshore platform structures. Alloy 725 can also be used to manufacture catalysts and catalytic reactors in the petrochemical industry.