X750 is a Nickel-Chromium alloy made precipitation hardenable by additions of Al and Ti, having creep-rupture strength at high temperatures to about 700°C (1290°F).
It is widely used for high temperature conditions but is not as strong as Nimonic 90.
| Chemical Composition | Specifications | Designations | Key Features | Typical Applications |
| ElementMin %Max %C-0.08Mn-1.00Si-0.50S-0.01Cr14.0017.00Ni70.00-Nb/Cb0.701.20Ti2.252.75Al0.401.00Fe5.009.00Co-1.00Ta-0.05Cu-0.50 | AMS 566 | W.NR 2.4669 | Good creep rupture strength at high temperatures | Nuclear reactors |
| 7AMS 5671 | UNS N07750 | Not as strong as Nimonic 90 | Gas turbines |
| AMS 5698 (No 1 Spring Temper) | AWS 014 | Very good at cryogenic temperatures | Rocket engines |
| AMS 5699 (Spring Temper) |
| Age hardenable | Pressure vessels |
| ASTM B637 |
| High temperature dynamic applications | Aircraft structures |
| BS HR 505 |
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| GE B14H41 |
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| ISO 15156-3 (NACE MR 0175) |
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| Density | 8.28g/cm³ | 0.299 lb/in³ |
| Melting Point | 1430°C | 2600°F |
| Coefficient of Expansion | 12.6 μm/m °C (20 - 100°C) | 7.0 x 10-6 in/in °F (70 - 212°F) |
| Modulus of Rigidity | 75.8 kN/mm² | 10994 ksi |
Modulus of Elasticity (Spring Temper + Aged) (Spring Temper + 3 Part Heat Treated) (No.1 Spring Temper + Aged) | 218.0 kN/mm²212.4 kN/mm²213.7 kN/mm² | 31619 ksi30806 ksi30995 ksi |
| Heat Treatment of Finished Parts |
| Condition as supplied by Alloy Wire | Type | Temperature | Time (Hr) | Cooling |
| °C | °F |
| Spring Temper | Age Harden | 650 | 1200 | 4 | Air |
| Spring Temper (3 Part) | AnnealStabalizeAge Harden | 1150843704 | 210015501300 | 2 †2420 | AirAirAir |
| No. 1 Temper | Age Harden | 730 | 1350 | 16 | Air |
| Properties |
| Condition | Approx. tensile strength | Approx. operating temperature |
| N/mm² | ksi | °C | °F |
| Annealed | 800 - 1000 | 116 - 145 | - | - |
| No 1 Temper | 900 - 1150 | 130 - 167 | - | - |
| Spring Temper | 1100 - 1500 | 159 - 217 | - | - |
| No 1 Temper + Aged | 1300 - 1450 | 188 - 210 | -200 to +550 | -330 to +1020 |
| Spring Temper + Aged | 1350 - 1750 | 196 - 254 | -200 to +370 | -330 to +700 |
| Spring Temper + 3 Part heat treated | 1100 - 1250 | 159 - 181 | -200 to +550 | -330 to +1020 |
