Nickel Alloy X-750
UNS N07750 · EN 2.4669 · also Inconel X-750
X-750 (UNS N07750, 2.4669, Inconel X-750) is a γ′ precipitation-hardenable Ni-Cr-Fe superalloy that combines oxidation and corrosion resistance with high strength and low stress relaxation up to about 700 °C.
Reference datasheet — X-750 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the STA condition
X-750 tempers and conditions
X-750 is supplied in 8 conditions, soft to hard. STA is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for forming, deep drawing and machining before age-hardening. | 345 | 830 | 45 | 180 HB | — |
Equalized | Intermediate stabilising treatment used on hot-rolled bar before ageing for bolting and springs. | 550 | 900 | 30 | 22 HRC | 1.4 % IACS |
Sheet/strip | Formed sheet parts (seals, bellows, diaphragms) aged after forming to reach service strength. | 700 | 1,140 | 26 | 28 HRC | 1.4 % IACS |
Triple heat treated | Choose for maximum creep-rupture life and notch ductility at 650–815 °C (turbine discs, hot bolting, nuclear internals). | 760 | 1,170 | 25 | 30 HRC | — |
STADefault Solution treated and aged | Standard stocked bar/forging condition: best all-round strength/ductility for bolts, shafts and fasteners to ~700 °C. | 815 | 1,200 | 24 | 32 HRC | — |
Equalized + aged | Highest room-temperature strength of the hot-finished bar conditions; typical for high-strength bolting and gas-turbine hardware below 650 °C. | 860 | 1,275 | 22 | 35 HRC | — |
No.1 Temper | As-supplied condition for coiling springs; wound cold then precipitation aged by the spring maker. | 1,240 | 1,450 | 6 | 42 HRC | 1.4 % IACS |
Spring temper + aged | Maximum strength and lowest relaxation — the standard condition for high-temperature springs and clips to ~650 °C. | 1,450 | 1,720 | 5 | 46 HRC | — |
What is X-750?
X-750 (UNS N07750, 2.4669, Inconel X-750) is a γ′ precipitation-hardenable Ni-Cr-Fe superalloy that combines oxidation and corrosion resistance with high strength and low stress relaxation up to about 700 °C. It is chosen for springs, hot bolting and turbine hardware and is stocked as bar, wire, strip, sheet and forgings in annealed, equalised, spring-temper and STA conditions; typical aged values are 815 MPa yield, 1200 MPa tensile, 24 % elongation and 32 HRC, with a maximum service temperature of 760 °C. Fabrication is the limit: machinability 18, formability 15 and weldability 40, with strain-age cracking risk if welded aged. Alloy 718 is the usual alternative where weld repair and machining dominate. X-750 has a density of 8.28 g/cm³ (0.299 lb/in³), lighter than 55% of nickel alloy grades. It melts at 1,393°C (2,539 °F). X-750 has a yield strength of 815 MPa (118 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 85% of nickel alloy grades. Elongation at break is 24% and the elastic modulus is 214 GPa (31 Msi).
What is X-750 used for?
- gas turbine blades and rings
- springs
- high-temperature bolts
- reactor core components
Advantages
- High strength — 815 MPa (118 ksi), better than 85% of nickel alloy grades
Limitations
- High embodied carbon — 17.5 kg CO₂/kg, worse than 98% of nickel alloy grades
- Limited formability — 15/100, worse than 81% of nickel alloy grades
X-750 properties
Typical room-temperature values for X-750-STA; bars are the position among nickel alloy grades.
Physical3
X-750 has a density of 8.28 g/cm³ (0.299 lb/in³), lighter than 55% of nickel alloy grades. It melts at 1,393°C (2,539 °F).
Mechanical16
X-750 has a yield strength of 815 MPa (118 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 85% of nickel alloy grades. Elongation at break is 24% and the elastic modulus is 214 GPa (31 Msi).
Thermal6
X-750 is rated for continuous service to 760°C (1,400 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), better than 65% of nickel alloy grades. Thermal expansion is 12.6 µm/m·K (7 µin/in·°F).
Electrical3
X-750 conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 51% of nickel alloy grades.
Sustainability4
Producing a kilogram of X-750 takes about 290 MJ of energy and emits 17.5 kg of CO₂ — more than 98% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability8
X-750's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability fair (40/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. X-750 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with X-750
Is X-750 easy to machine?
Machine in the annealed or solution-treated condition where possible; use rigid setups, positive-rake carbide or ceramic tooling, low speed/heavy feed and flood coolant — work hardens rapidly and notches tools like most γ′ superalloys.
Can X-750 be welded?
GTAW/EB weld in the solution-annealed condition with Inconel 69/718-type or matching filler, then re-solution and re-age; welding in the aged condition invites strain-age (post-weld heat-treat) cracking in the HAZ.
Can X-750 be formed, bent or molded?
Cold-form, deep-draw or coil springs in the annealed/spring-temper condition with generous bend radii and frequent interstage anneals; hot work 1150–1230 °C and finish above 950 °C.
X-750 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cr | 14 – 17 | 15.5 |
| Fe | 5 – 9 | 7 |
| Ti | 2.25 – 2.75 | 2.5 |
| Al | 0.4 – 1 | 0.7 |
| NbNb + Ta | 0.7 – 1.2 | 0.95 |
| Co | ≤ 1 | 0.3 |
| Mn | ≤ 1 | 0.3 |
| Si | ≤ 0.5 | 0.2 |
| Cu | ≤ 0.5 | 0.1 |
| C | ≤ 0.08 | 0.04 |
| S | ≤ 0.01 | 0 |
| NiNi + Co, balance | ≥ 70 (balance) |
What surface finishes work on X-750?
Not anodizable — finish by pickling/passivation, abrasive or electro-polishing; shot peening markedly improves fatigue and SCC life, and silver or dry-film lubricant coatings are used on hot bolting to prevent galling.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Nickel Alloy X-750 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N07750
- EN / DIN / Werkstoff-Nr.
- 2.4669
- Trade names
- Inconel X-750
How much does X-750 cost?
X-750 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
X-750 — frequently asked
What is X-750 used for?
X-750 is typically used for gas turbine blades and rings, springs, high-temperature bolts and reactor core components. In short: best spring superalloy; low relaxation to 700 °C; hot bolting standard.
What is the yield strength of X-750?
X-750 has a typical yield strength of 815 MPa (118 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 85% of nickel alloy grades. Strength varies by condition: see the 8 listed tempers.
Is X-750 easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% of nickel alloy grades). Machine in the annealed or solution-treated condition where possible; use rigid setups, positive-rake carbide or ceramic tooling, low speed/heavy feed and flood coolant — work hardens rapidly and notches tools like most γ′ superalloys.
Can X-750 be welded?
With care — weldability is rated fair (40/100). GTAW/EB weld in the solution-annealed condition with Inconel 69/718-type or matching filler, then re-solution and re-age; welding in the aged condition invites strain-age (post-weld heat-treat) cracking in the HAZ.
What surface finishes work on X-750?
Not anodizable — finish by pickling/passivation, abrasive or electro-polishing; shot peening markedly improves fatigue and SCC life, and silver or dry-film lubricant coatings are used on hot bolting to prevent galling.
Can X-750 be formed, bent or molded?
Cold-form, deep-draw or coil springs in the annealed/spring-temper condition with generous bend radii and frequent interstage anneals; hot work 1150–1230 °C and finish above 950 °C.
What is the maximum service temperature of X-750?
X-750 is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between X-750-STA and X-750 SPR-A?
STA is the default condition — standard stocked bar/forging condition: best all-round strength/ductility for bolts, shafts and fasteners to ~700 °C. SPR-A: maximum strength and lowest relaxation — the standard condition for high-temperature springs and clips to ~650 °C. Yield strength is 815 MPa in STA versus 1,450 MPa in SPR-A.
How much does X-750 cost?
X-750 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- INCONEL alloy X-750 technical bulletin — Special Metals Corporation (2004)
- ASTM B637 – Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings and Forging Stock for Moderate or High Temperature Service — ASTM International (2018)
- AMS 5667 / AMS 5668 / AMS 5670 / AMS 5698 – Alloy Bars, Wire and Springs, UNS N07750 — SAE International (2019)
- AMS 5542 – Nickel Alloy Sheet, Strip and Plate, Solution Heat Treated (UNS N07750) — SAE International (2018)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 – Machining — ASM International (1989)
- High-Temperature Characteristics of Stainless Steels / Nickel Alloy Data — Nickel Institute (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.