Views:67 Author:Site Editor Publish Time: 2021-07-31 Origin:Site
2.4611 high-temperature alloy is a high-temperature alloy of 760℃800MPa grade high-temperature material. Casting high-temperature alloy refers to a type of high-temperature alloy that can or can only be formed by casting methods. Its main features are:
1. It has a wider range of composition. Since it is not necessary to take into account its deformation processing performance, the design of the alloy can focus on optimizing its use performance. For example, for nickel-based superalloys, the content of γ'can be adjusted to 60% or higher by adjusting the composition, so that the alloy can still maintain excellent performance at a temperature as high as 85% of the melting point of the alloy.
2. It has a broader application field. Due to the special advantages of the casting method, it is possible to design and manufacture near-net shape or no margin high-temperature alloy castings with arbitrary complex structures and shapes according to the use needs of the parts.
According to the service temperature of the casting alloy, it can be divided into the following three categories:
Type 1: Equiaxed crystal casting superalloys used at -253～650℃. These alloys have good comprehensive properties in a wide range of temperatures, and they can maintain strength and plasticity at low temperatures without decreasing. For example, the Monel K500 alloy, which is used in aerospace and aerospace engines, has a tensile strength of 1000 MPa, a yield strength of 850 MPa, and a tensile plasticity of 15% at 650°C; its endurance life under stress at 650°C and 620 MPa is 200 hours. It has been used in the manufacture of diffuser casings in aero-engines and various complex structural parts for pumps in aerospace engines.
Type 2: Equiaxed crystal casting superalloys used at 650～950℃. These alloys have higher mechanical properties and thermal corrosion resistance at high temperatures. For example, K419 alloy, at 950°C, the tensile strength is greater than 700MPa, and the tensile ductility is greater than 6%; at 950°C, the endurance strength limit for 200 hours is greater than 230MPa. This type of alloy is suitable for use as aero-engine turbine blades, guide vanes and cast turbines.
Type 3: Directionally solidified columnar crystals and single crystal superalloys used at 950～1100℃ have excellent comprehensive performance and thermal corrosion resistance in this temperature range. For example, DD402 single crystal alloy has a durability life of more than 100 hours under a stress of 1100°C and 130MPa. This is a turbine blade material of domestic use temperature, which is suitable for making the first-stage turbine blade of a new high-performance engine.
With the continuous improvement of precision casting technology, new special processes are also emerging. Fine-grain casting technology, directional solidification technology, CA technology of complex thin-walled structural parts, etc. have greatly improved the level of casting high-temperature alloys, and the scope of application has continued to increase.