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. It is widely
used for high temperature conditions but is not as strong as
Nimonic 90. Without the addition of Co X750 for nuclear
reactors.
Applications include:
- Nuclear reactors
- Gas turbines
- Rocket engines
- Pressure vessels
- Aircraft structures
| Approximate Chemical Composition | |
| Ni + Co | 70% Minimum |
| CR | 14-17% |
| Fe | 5-9% |
| Ti | 2.25-2.75% |
| Al | 0.4-1.0% |
| Nb | 0.7-1.2 |
| DENSITY | 8.28 g/cm3 | 0.299 lb/in3 | |
| MELTING POINT | 1430 oC | 2600 oF | |
| 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/m2 | 10994 ksi | |
| MODULUS OF ELASTICITY | * ** *** |
218.0 kN/m2 212.4 kN/m2 213.7 kN/m2 |
31619 ksi 30806 ksi 30995 ksi |
*Spring Temper + Aged **Spring Temper + 3 Part Heat Treated
*** No.1 Spring Temper + Aged
*** No.1 Spring Temper + Aged
| CONDITION OF SUPPLY | HEAT TREATMENT (AFTER FORMING) |
| Spring Temper | Age harden at 650oC for 4 hours and air cool. |
| Spring Temper | 3 Part Heat Treatment: *1. Solution Anneal at 1150ºC (2100ºF) for 2 hours and air cool 2. and Stabilise at 843ºC (1550ºF) for 24 hours and air cool 3. and Age harden at 704ºC (1300ºF) for 20 hours and air cool |
| No 1 Spring Temper | Age harden at 730ºC (1350ºF) for 16 hours and air cool |
*for diameters below 1.00mm contact AWI technical department.
| CONDITION | APPROX TENSILE STRENGTH | APPROX SERVICE TEMPERATURE | ||||
| Annealed |
|
|||||
| Spring Temper |
|
|||||
| Spring Temper + Aged |
|
|
||||
| Spring Temper + 3 part heat treated |
|
|
||||
| No 1 Spring Temper |
|
|||||
| No 1 Spring Temper + Aged |
|
|
| STANDARDS | ||||
| AMS 5667 | AMS 5669 (Spring Temper) |
AMS 5698 (No 1 Spring Temper) |
ASTM B637 | BS HR 505 |
