What material is uns n07750?
Alloy X-750 is a nickel-chromium alloy made precipitation hardenable by the addition of aluminum and titanium. Alloy X-750 has good corrosion and oxidation resistance and high tensile and creep-rupture properties at temperatures up to 1300ºF (700ºC). X-750 is used as high temperature springs and bolts due to its excellent resistance to relaxation, and is also used in gas turbines, rocket engines, nuclear reactors, pressure vessels, tooling, and aircraft structures.
| Chemical Composition Limits | ||||||||||||
| Weight % | Ni +(Co) | Cr | Fe | Ti | Al | Nb + (Ta) | Mn | Si | S | Cu | C | Co |
| X-750 UNS N07750 |
70 min | 14-17 | 5-9 | 2.25-2.75 | 0.40-1.0 | 0.70-1.2 | 1 max | 0.50 max | 0.01 max | 0.50 max | 0.08 max | 1 max |
| UNS N07752 is available in billets for forging. UNS N0772 has limits of 0.05% on both Carbon and Cobalt | ||||||||||||
Typical Mechanical Properties
| Material | Size | Ultimate Tensile Strength ksi |
Yield Strength (0.2% Offset) Ksi | Elongation in 4D(%) | % Reduction of Area |
| Alloy X-750 Bar | Under 4.0" | 165.0 | 105 | 20 | 25 |
| Alloy X-750 Bar | 4.0 " and over | 160 | 100 | 15 | 17 |
| Properties as described in AMS 5667 which requires that material following 1625°F/24 hrs, AC-Equalising + precipitation treatment have the following minimum room temperature properties. Hardness will lie in the range of 302-363 BHN | |||||
Bars, Rods and Forgings are available with the following heat treatments
AMS 5667 - 1625°F/24 hrs, AC + 1300°F/20 hrs, AC (Homogenize plus Precipitation Treatment). AMS 5667 Bars, Rods and Forgings have high strength and notched rupture ductility up to 1100°F
AMS 5668 - 2100°F Annealed + 1550°F/24 hrs, AC, +1300°F/20 hrs, AC (Triple Heat Treat). AMS 5668 has maximum creep, relaxation and rupture strength above 1100°F.
AMS 5670 - 1800°F Annealed + 1350°F/8 hrs, FC to 1150°F. Total aging time is 18 hours at 1150°F, AC (solution treated plus furnace aging). AMS 5670, AMS 5671, and AMS 5747 have improved tensile properties due to heat treatment and have shorter heat treatment times, with a maximum temperature of about 1100°F.
Heat treatment is 1800°F anneal + 1400°F/1 hour, FC to 1150°F, with a total aging time of 6 hours at 1150°F, AC (solution treated plus short furnace aging). This short furnace cooling aging treatment has properties only slightly inferior to AMS 5670 and AMS 5671.
X-750 bars and rods are available in diameters from 1/2-inch to 6-inch in 1/4-inch increments. Diameters range from 6-inch to 10-inch in 1/2-inch increments.
| Material | Size | Tensile Strength ksi | Yield Strength (0.2% Offset) Ksi | Elongation in 2"(%) | % Hardness Rc |
| Alloy X-750 Sheet Annealed Condition |
0.010 to 0.024", incl | 140 max | - | 30 min | - |
| Alloy X-750 Sheet Annealed Condition |
over 0.024 - 0.125" incl | 130 max | 60 max | 40 min | - |
| Alloy X-750 Sheet Annealed Condition |
over 0.125 - 0.250 incl | 130 max | 65 max | 40 min | - |
| Alloy X-750 Sheet After Precipitation Treating (1300°F/20hr, A.C) |
0.010 to 0.025 incl | 165 min | 105 min | 20 min | 32 min |
| Alloy X-750 Plate After Precipitation Treating (1300°F/20hr, A.C) |
0.187 to 4.000, excl | 155 min | 100 min | 20 min | 30 min |
