Inconel X750

Inconel X750 (also known as UNS N07750) is a nickel-chromium alloy, blended with aluminum and titanium to make it precipitation-hardenable. It is corrosion and oxidation resistant and has good mechanical properties at elevated temperatures up to 700°C (1290°F), including high tensile and creep-rupture strength. Additionally, in the solution and precipitation heat treated condition Inco X750 has good strength and toughness. As a result, IN X750 is often used in parts and structures that work at high temperature conditions. Typical aerospace applications include rotor blades, wheel and bolts for gas turbines, jet and rocket engine thrust chambers, hot air ducting systems and thrust reversers for airframes. It is also used for large pressure vessels, forming tools, extrusion dies, nuclear power plant applications and heat-treating fixtures.

At Rickard Specialty Metals, we have 30 years experience supplying inconel x750 forgings and many other product forms to your custom measurements and shapes. Our forging process includes open die forgings, ring rolling and more. See below for a list of the common forged shapes and product forms we offer.

Inconel X750 Additional Information:

Physical Properties

Hardness: HRC 32 – 42 in the solution and precipitation heat treated condition (depending on heat treatment).
Density: 0.299 lbs per cubic inch.
Modulus of Elasticity: 31 MSI in STA condition.
Coefficient of Expansion: 7.8 x10-6 in/in/F, RT-800F. 8.4 x10-6 in/in/F, RT-1200F.

Machining

Inco X750 has a Machinability rating of 16. Like other nickel-base superalloys, the machinability of Inconel X-750 is inferior to that of most steels including stainless steels. Nevertheless, with proper selection of tool materials, speeds, feeds, and coolants, it can be machined in either the annealed or age-hardened condition. Due to the strength and hardness of Inco X750, one should perform any rough machining before precipitation hardening.

Welding

Inconel X750 has fair welding ability, particularly in conjunction with gas-tungsten-arc (GTA), plasma-arc, and electron-beam welding. Inconel 718 weld filler is the preferred choice to help resist strain age cracking. Welding is generally carried out on solution annealed material and appropriate post-weld heat treatment is employed to develop the desired properties. The precipitation hardened alloy is also weldable, but weld joints are susceptible to cracking and will be relatively soft and weak until heat treated. A full post-weld solution, anneal and precipitation heat treatment is most often applied to obtain optimum properties in weldments.

Forming

Forming for Inconel X-750 is fair to good in the solution annealed condition. Due to its rapid strain hardening rate, frequent in-process anneals are necessary when complex shapes are desired.

Corrosion Resistance

Inco X750 has good resistance to general corrosion and stress corrosion over a wide range of temperatures under both oxidizing and reducing conditions.

Heat Treatment

Inconel X750 heat treatment will differ depending on the mechanical application and properties required. See the table below for an outline of heat treatment recommendations by product form and specification:

Product Form	AMS Specifications	Inconel X750 Heat Treatment	Results
Rods, bars and forgings	AMS 5667	1625°F/24 hr, AC, + 1300°F/20 hr, AC (Equalizing plus precipitation treatment)	High strength and notch rupture ductility up to 1100°F.
Rods, bars and forgings	AMS 5670, 5671 and 5747	1800°F anneal + 1350°F/8 hr, FC to 1150°F, Hold at 1150°F for total precipitation-treating time of 18 hr, AC (Solution treatment plus furnace-cool precipitation treatment).	Increased tensile properties and reduced heat treating time for service up to about 1100°F.
Rods, bars and forgings	AMS 5668	2100°F anneal + 1550°F/24 hr, AC, + 1300°F/20 hr, AC (Triple heat treatment).	Maximum creep, relaxation and rupture strength above about 1100°F.
Sheet, strip and plate (Supplied in annealed condition)	AMS 5542	1300°F/20 hr, AC (Constant-temperature precipitation treatment).	High strength to 1300°F.
Sheet, strip and plate (Supplied in annealed condition)	AMS 5598	1350°F/8 hr, FC to 1150°F, Hold at 1150°F for total precipitation-treating time of 18 hr, AC (Furnace-cool precipitation treatment).	High strength up to 1300°F (Increased tensile properties to about 1100°F).
Wire, No. 1 temper	AMS 5698	1350°F/16 hr, AC (Constant-temperature precipitation treatment).	For springs requiring optimum resistance to relaxation from about 700°F to 850°F and at low to moderate stresses to about 1000°F.
Wire, spring temper	AMS 5699	1200°F/4 hr, AC (Constant-temperature precipitation treatment)	High strength up to about 700°F.
Wire, spring temper	AMS 5699	2100°F anneal + 1550°F/24 hr, AC + 1300°F/20 hr, AC (Triple heat treatment).	For springs for service requiring maximum relaxation resistance at about 850°F to 1200°F.

Forging

Inconel X750 forging can be performed by techniques common in the industry, including hot and cold forming. Make sure to choose procedures and tools that can best be applied to the high strength and hardness of the alloy. The recommended temperature range for hot working Inconel X-750 is 1800°-2200°F. The alloy will be difficult to work with when performed below 1800°F, which may cause splitting.

Specimen Orientation	Tensile Strength	Yield Strength at 0.2% Offset	Elongation in 4D %	Reduction of Area %
Longitudinal	170 KSI	115 KSI	18	18
Transverse (Bars)	165 KSI	110 KSI	15	15

Product	Nominal Thickness (Inches)	Tensile Strength (KSI)	Yield Strength at 0.2% Offset (KSI)	Elongation in 2 Inches or 4D %
X750 Strip	Up to 0.010, excl	150 KSI	—	—
	0.010 to 0.025, excl	155 KSI	—	15
	0.025 to 0.1874, incl	155 KSI	—	15
X750 Sheet	0.010 to 0.1874, incl	165 KSI	105	20
X750 Plate	0.1875 to 4.000, incl	155 KSI	100	20