Nickel-based super alloy: Inconel X-750 (UNS N07750/W.NR 2.4669)

What is Inconel X-750?

Inconel X-750 alloy is mainly a nickel base superalloy aged with γ′ [Ni3 (al, Ti, Nb)] phase. It has good corrosion resistance and oxidation resistance below 980 ℃, high strength below 800 ℃, good relaxation resistance below 540 ℃, and good formability and weldability. The alloy is mainly used to make annular parts, structural parts and bolts with high strength and corrosion resistance, plane spring and coil spring with medium or low stress and relaxation resistance working below 540 ℃. It can also be used to manufacture turbine blades and other parts. The products available are plate, strip, bar, forging, ring, wire and tube.

Designated as UNS N07750 or W. Nr. 2.4669, Inconel X750, also known as “Alloy X750”, is a nickel-chromium alloy similar to Inconel 600 but made precipitation hardenable by additions of aluminum and titanium. The alloy has good resistance to corrosion and oxidation along with high tensile and creep-rupture properties at temperatures up to about 1300°F(700°F). Its excellent relaxation resistance is useful for high-temperature springs and bolts. The Inconel X-750 can also be used in gas turbines, rocket engines, nuclear reactors, pressure vessels, tooling, and aircraft structures.

Characteristics of Inconel X-750 (UNS N07750/W.NR 2.4669)

  • Iron-Nickel-Chromium based alloy hardened by precipitation of elements aluminium and titanium
  • Good corrosion resistance and oxidation resistance even at high temperatures to 980°C, 
  • Good mechanical strength until 800°C, 
  • Good relaxation resistance until 540°C,
  • Good processability and weldability,
  • Excellent mechanical properties in low temperature environment. 

Chemical Composition of Inconel X-750 (UNS N07750/W.NR 2.4669):

C

Cr

Ni+Co

Fe

Mn

Si

S

Al

Ti

Co

Cu

Nb+Ta

≤0.08

14.0-17.0

≥70.0

5.0-9.0

≤1.0

≤0.5

≤0.01

0.4-1.0

2.25-2.75

≤1.0

≤0.5

0.7-1.2

Mechanical Properties of Inconel X-750 (UNS N07750/W.NR 2.4669)

Density Melting Range Curie Temperature,°F Magnetic Permeability, 70°F, 200H Linear Contraction during Precipitation Treatment(1300°F/20hr), in/in
lb/in3 g/cm3 °F °C As hot-rolled As Hot-Rolled Hot-Rolled 20% Cold-Rolled Annealed
0.299 8.28 2540-2600 1393-1427 -225 1.0020 0.00044 0.00052 0.00026

Physical Properties of Inconel X-750 (UNS N07750/W.NR 2.4669)

Density 
(g/cm3)

Elastic modulus
(GPa)

Melting point
(℃)

8.24 

204.9

1260~1320 

Thermal conductivity
(W(m•℃))

Hardness
(HBS)

 Thermal expansion coefficient( 21 – 93°C)
10-6×m/m °C

14.7

346-450

13.0 

Product Forms and Standards

Products Form Standard
Rod, Bar and Forging ASTM B637, ISO 9723-9725
Plate, Sheet and Strip ISO 6208
Wire BS HR 505

Heat treatment system of Inconel X-750 (UNS N07750/W.NR 2.4669):

The temperature of hot strip is 980 ℃ and the temperature of hot strip is 980 ℃. For the intermediate heat treatment system of materials and parts, the following processes can be selected for heat treatment.

  • (1) Annealing: 955 ~ 1010 ℃, water cooling.
  • (2) Annealing before welding: 980 ℃, 1H.
  • (3) Stress relief annealing: 900 ℃ for 2 h.
  • (4) Stress relief annealing: 885 ℃± 15 ℃, 24h, air cooling.

Heat treatment process of inconelx-750 parts:

Heat treatment of parts shall be carried out in neutral or reducing atmosphere without sulfur to avoid vulcanization. Parts should be avoided from “hot cold” treatment between 870 ℃ and 650 ℃. For parts with large cross-section, in order to prevent cracks, the parts should be cooled in air after solution treatment. The final heat treatment of finished parts is as follows:
(1) For parts working above 600 ℃ and requiring the best creep resistance:

  • Solid solution: 1150 ℃± 15 ℃, holding for 2-4h, air cooling;

  • Aging: 845 ℃± 15 ℃, holding for 24h, air cooling + 705 ℃± 15 ℃, holding for 24h, air cooling.

(2) For parts working below 600 ℃ and requiring the best room temperature and high temperature tensile properties:

  • Solid solution: 980 ℃± 15 ℃, holding for 1h, air cooling;

  • Aging: 730 ℃± 15 ℃, holding for 8h, furnace cooling at 50 ℃ / h to 620 ℃± 10 ℃, holding for 8h, air cooling.

(3) The following heat treatment systems are generally used for annular parts:

  • Solid solution: 1095 ℃± 15 ℃, holding for 2-4h, air cooling;
  • Aging: 845 ℃± 15 ℃, holding for 24h, air or furnace cooling to + 705 ℃± 15 ℃, holding for 20h, air cooling.

(4) The following systems shall be used for heat treatment of bars and forgings at temperatures below 600 ℃

  • Homogenization: 885 ℃± 15 ℃, heat preservation for 24h, air cooling;

  • Aging: 705 ℃± 15 ℃, holding 20 ± 1H, air cooling.

(5) Plate and strip in annealed state and plate, strip and wire used for spring can be heat treated with the following system:
Aging:
1) 705 ℃± 15 ℃, holding for 22h, air cooling;
2) 760 ℃± 10 ℃, holding for 1 h, air cooling.

  • Solid solution: 980 ℃± 15 ℃, holding for 1h, air cooling;

  • Aging: 730 ℃± 10 ℃, holding for 8h, furnace cooling at 50 ℃ / h to + 620 ℃± 10 ℃, holding for 8h, air cooling.

Melting and casting process of Inconel X-750 (UNS N07750/W.NR 2.4669):

The alloy is remelted by arc furnace plus vacuum consumable remelting, vacuum induction plus electroslag, electroslag plus vacuum consumable remelting or vacuum induction plus vacuum consumable remelting.

Process performance and requirements of inconelx-750:

  • 1. The forming properties of inconelx-750 are as follows The forging temperature of the alloy ranges from 1220 ℃ to 950 ℃. In order to obtain good microstructure and properties of the final forging or bar, the subsequent forging heating temperature should be carried out at the corresponding lower temperature. The final forging temperature should not be lower than 950 ℃. The alloy should be treated by solid solution after vigorous forming.
  • 2. Inconelx-750 welding performance: The alloy has good weldability and can be welded in various ways, but it is difficult to weld large section parts, but it is better to weld small section parts and thin plates. The welding must be carried out after annealing or solution treatment, and stress relief treatment should be carried out after welding, and the humidity should be kept at 980 ℃ for 0.5h or 900 ℃ for 2h. After aging treatment, the strength of the welded assembly in the state of approximate complete heat treatment can be obtained.

Thermal performance of Inconel X-750 (UNS N07750/W.NR 2.4669):

Thermal conductivity of Inconel X-750:

θ/℃ 50 100 300 500 900
λ/(W/(m·℃)) 14.7 15.9 20.1 25.1 37.3

Coefficient of linear expansion of Inconel X-750:

θ/℃ 20~200 20~300 20~400 20~500 20~600 20~700 20~800
α/10-6-1 13.1 13.5 14.1 14.4 15.0 15.6 16.2

Welding performance of Inconel X-750 (UNS N07750/W.NR 2.4669):

The alloy has good weldability and can be welded in various ways, but it is difficult to weld large section parts, but it is better to weld small section parts and thin plates. The welding must be carried out after annealing or solution treatment, and stress relief treatment should be carried out after welding, and the humidity should be kept at 980 ℃ for 0.5h or 900 ℃ for 2h. After aging treatment, the strength of the welded assembly in the state of approximate complete heat treatment can be obtained.

Application areas of nickel-based alloy inconel X-750 (UNS N07750/W.NR 2.4669):

  • Heat treatment factories with tray,basket and fixture.
  • Steel wire annealing and radiant tube, high-speed gas burner,the mesh belt furnace.
  • The ammonia reforming in the isolation tank and the catalytic support grid for production of nitric acid.
  • Heating pipes, containers, baskets and chains used in sulfuric acid pickling plants.
  • Exhaust system components.
  • Piping system.
  • The solid waste incinerator combustion chamber.
  • Pipe supports and ash handling part.
  • Exhaust detoxification system components.
  • Oxygen to the heater.
  • Heat exchange tubes.
  • Pipe fittings.
  • Flanges.
  • Valves.

Variety specifications and supply status of Nickel-based super alloy: Inconel X-750 (UNS N07750/W.NR 2.4669):

Variety classification:

Yaang Pipe Industry can produce various specifications of Inconel X-750 seamless pipe, Inconel X-750 steel plate, Inconel X-750 round bar, Inconel X-750 forgings, Inconel X-750 flangeInconel X-750 pipe fittings, Inconel X-750 welded pipe, Inconel X-750 steel strip, Inconel X-750 wire and supporting welding materials. 

Delivery status:

  • Seamless pipe: solid solution + acid white, length can be set;
  • Plate: solid solution, pickling, trimming;
  • Welded pipe: solid solution acid white + RT% flaw detection;
  • Forging: annealing + car polish; Bars are forged and rolled, surface polished or car polished;
  • Strips are delivered after cold rolling, solid solution soft state, and deoxidized;
  • Wire rods are finely ground in solid solution pickled disk or straight strips, solid solution straight strips Delivery in light state.

Source: China Inconel X-750 Flanges Manufcturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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Summary
nickel based super alloy incoloy 825 uns n08825 w nr 2 4858 - Nickel-based super alloy: Inconel X-750 (UNS N07750/W.NR 2.4669)
Article Name
Nickel-based super alloy: Inconel X-750 (UNS N07750/W.NR 2.4669)
Description
Inconel X-750 alloy is mainly a nickel base superalloy aged with γ′ [Ni3 (al, Ti, Nb)] phase. It has good corrosion resistance and oxidation resistance below 980 ℃, high strength below 800 ℃, good relaxation resistance below 540 ℃, and good formability and weldability.
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www.steeljrv.com
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