Learn about our high-performance Nickel-Chromium Alloy, X750. Used Primarily in Aerospace & the Oil & Gas Industry.
X750 Overview
通常被称为 铬镍铁合金® 合金 X-750，这种高性能奥氏体镍铬合金通过添加铝和钛可进行沉淀硬化。它具有良好的抗腐蚀和抗氧化性，以及在高温下的高拉伸和蠕变断裂性能。对于在高温下需要高强度的扩展应用， Alloy X750 可能需要固溶处理，在中间时效和最终时效之间进行空气冷却。
Alloy X750 displays excellent workability, including machinability and welding. Alloy X750 has excellent relaxation resistance, good elevated temperature strength properties to 1300ºF (700°C), and oxidation resistance to 1800ºF (983˚C).
Alloy X750 is resistant to a wide variety of industrial corrosives under both oxidizing and reducing conditions, while also displaying excellent resistance to chloride stress corrosion cracking in fully age-hardened conditions.
X750 Composition
| C | 锰 | 硅 | 小号 | 铬 | 你 | 铅（铌） | 钛 | 铝 | 铁 | 公司 | 塔 | 铜 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 敏 | 14.0 | 70.0 | 0.70 | 2.25 | 0.40 | 5.0 | |||||||
| 最大限度 | 0.08 | 1.00 | 0.50 | 0.01 | 17.0 | 1.20 | 2.75 | 1.00 | 9.0 | 1.0 | 0.05 | 0.50 |
行业标准
Commercial applications of Alloy X750 are governed by a range of established industry standards to ensure quality, consistency, and performance in demanding environments. Key specifications include AMS 5698, AMS 5699, NACE MR0175 (ISO 15156-3), NACE MR0103 (ISO 17945), ASTM B637, and MIL-DTL-24493, covering various aspects of material properties, corrosion resistance, and heat treatment requirements.
For Aerospace applications, X750 must meet the stricter requirements of AMS 5678G, which introduces additional qualification tests beyond standard specifications. This standard mandates further control of the alloy’s microstructure and mechanical properties in the final drawn wire, ensuring it meets the rigorous performance demands of aerospace components, including high-temperature and high-stress environments.
Applicable Specifications for Wire & Bar: AMS 5698, AMS 5699, NACE MR0175 (ISO 15156‐3), NACE MR0103 (ISO 17945), ASTM B637, MIL‐DTL‐24493
微观结构方面
It has been reported that the SCC resistance of Inconel X-750 can be improved by direct aging in the precipitation regime of 704°C to 8710°C. Therefore, the microstructural changes that occur when Inconel X750 is thermally treated between 7040°C and 8710°C for up to 200 hours following a 2-hour solution anneal at 10750°C, 11490°C, or 12040°C has been studied.
The coarsening kinetics of the γ’ particle growth obeyed the time-law prediction of Lipshitz-Slazor-Wagner theory of diffusion controlled growth at all aging temperatures. The γ’ precipitate lost coherency by the nucleation of dislocation loops within the precipitate, the interaction of dislocation at the interface and attraction of matrix dislocations to the particle/matrix interface.
应用领域
With Alloy X750’s excellent relaxation resistance it is useful for applications such as high-temperature springs and bolts. Alloy X750 is commonly used in:
- 燃气轮机
- 推力反向器
- 轮子
- 管道
- 光盘
- 飞机结构
- 火箭发动机
- 核反应堆
- 热处理夹具
- 低温容器
- 低温弹簧
- 低温紧固件
- 排气阀
- 工业压力容器
- 工装
Physical Properties
| Physical Properties | At 70°F | At 1000°F | At 20°C | At 538°C |
|---|---|---|---|---|
| Density | 0.299 lb/in³ | 8.28 g/cm³ | ||
| Modulus of Elasticity (E) | 31.0 x 10⁶ psi | 26.7 x 10⁶ psi | 214 GPa | 184 GPa |
| Modulus of Rigidity (G) | 12.0 x 10⁶ psi | 82.7 GPa | ||
| Coefficient of Expansion | 7.8 µin/in-°F (70°F to 1000°F) | 14.5 µm/m-°C (20°C to 538°C) | ||
| Electrical Resistivity | 20.1 µ ohm.in | 122 µΩ.cm | ||
| Thermal Conductivity | 83 Btu·in/ft²·hr·°F | 12.0 W/m·K |
Typical Mechanical Properties
| Condition | Heat Treatment | 抗拉强度 | Suggested Operating Conditions |
|---|---|---|---|
| Solution Treated | 2000 – 2200°F (1093 – 1204°C) |
130 ksi max (896 MPa max) |
|
| No. 1 Temper (AMS 5698) | As supplied condition. | 130 – 165 ksi (896 – 1140 MPa) |
Optimum resistance to relaxation at temperatures up to 1000°F (538°C) with moderate or low stresses. |
| No. 1 Temper + Aged | 1350°F (732°C) for 16 hours | 165 – 220 ksi (1140 – 1520 MPa) |
Optimum resistance to relaxation at temperatures up to 1000°F (538°C) with moderate or low stresses. |
| Spring Temper (AMS 5699) | As supplied condition. | 160 – 200 ksi (1100 – 1380 MPa) |
|
| Spring Temper + Aged | After spring coiling: age 1200°F (649°C) minimum for 4 hours | 180 – 260 ksi (1240 – 1795 MPa) |
Optimum resistance to relaxation at temperatures up to 700°F (371°C) with low stresses. |
| Spring Temper + Solution + Aged (3 Step Heat treatment) |
After spring coiling: Solution Heat Treat 2000°F (1093°C) for 2 hours and air cool. Age Harden at 1350°F (732°C) for 4 hours and air cool. Reheat to 1300°F (704°C) for 20 hours and air cool. | 145 – 190 ksi (1000 – 1310 MPa) |
Optimum resistance to relaxation at temperatures in the range 1000 – 1300°F (538 – 704°C). |
