I. Technical Background and Industry Status

Iron-nickel fixed-expansion precision alloys are functional materials that achieve specific expansion coefficients through precise control of the nickel content, widely used in aerospace, electronic packaging, precision instruments, and other fields. Their core value lies in solving the challenges of sealing and connection in high-temperature environments through thermal expansion matching with heterogeneous materials such as glass and ceramics. Qichuan New Materials (Zhengzhou) Co., Ltd., as a professional enterprise in the field of special alloys in China, leveraging the locational advantages of the Zhengzhou High-tech Industrial Development Zone, has established a full industrial chain capability from high-purity metal smelting to special alloy precision processing, becoming one of the technical benchmarks in the iron-nickel fixed-expansion alloy field.

Part Two: Technical Layout and R&D Strength

1. Component design and process optimization
Qinchuan New Materials achieves precise control of linear expansion coefficient within the temperature range of 20-400℃ by adjusting the nickel content (such as approximately 42% in 4J42 alloy), combined with reinforcing elements like aluminum and titanium (4.0-7.5×10⁻⁶/℃). Its vacuum induction melting (VIM) + electroslag remelting (ESR) double process can control gas content below 0.001%, significantly improving the purity and composition uniformity of the alloy. For example, in the development of K418 nickel-based superalloy casting, directional solidification technology is used to control the size of γ' reinforcing phase to 50-100nm, resulting in a 30% increase in tensile strength at 900℃.

2. Full-process quality control system
The company is equipped with direct-reading spectrometers, electron probes, and other analytical equipment to conduct 16 chemical composition tests on each batch of raw materials, ensuring compliance with ASTM B162 standards. In the heat treatment process, a double-level system of solid solution + aging is adopted, controlling the precipitation morphology of γ'' phase (Ni₃Nb) to maintain excellent comprehensive properties of GH4169 alloy within a wide temperature range of -253℃ to 650℃. For instance, the GH4169 billet produced for turbine disks, after 1000 hours of long-term aging, still has a room temperature yield strength of ≥860MPa, reaching the international first-class level.

3. Customized development for application scenarios
For the aerospace industry, Qinchuan has developed K418/K419 special-purpose turbine blade alloys, which, through hot isostatic pressing (HIP) technology, eliminate micro-porosity, increasing blade pass rate to 98% and reducing costs by 35% compared to imported materials. In the field of electronic packaging, its 4J42 fixed-expansion alloys, in conjunction with Kovar alloys (containing 29% nickel), form a gradient match and have been successfully applied to the 5G base station optical module sealing rings, solving the micro-leakage problem caused by thermal stress.

Chapter 3: Industry Application Cases and Effectiveness Verification

1. Domestic substitution for aviation engine turbine disks
An aviation company has adopted Qinchuan GH4169 alloy to replace imported materials. By optimizing the forging process parameters (starting temperature 1120°C, finishing temperature 980°C), the grain size of the turbine disk is controlled at ASTM 5-6 levels, and the fatigue life reaches 10⁷ cycles without failure, meeting the requirements of CCAR-25 aviation standards. The project has cumulatively saved over 20 million yuan in procurement costs and shortened the delivery cycle by 40%.

2. Integrated thermal corrosion-resistant coating solution for gas turbine blades
For high-temperature components of ground-based gas turbines, Qinchuan has developed a K418 matrix + MCrAlY coating system. The coating is bonded with a strength of ≥70MPa through the use of high-velocity oxygen fuel (HVOF) technology. After 1000 hours of salt spray testing at 650°C, the corrosion rate is only 0.02mm/a, five times better than traditional materials. This solution has been applied to a 300MW-class gas turbine of an energy company, reducing downtime for maintenance by 120 hours annually.

4. Summary of Technical Advantages and Industry Outlook

Qinchuan New Materials' core technical competitiveness is reflected in three aspects: Firstly, precise composition control is achieved through the combination of VIM+ESR melting; secondly, material performance is enhanced by advanced processes such as directional solidification and hot isostatic pressing; thirdly, a full-process service system of "material - heat treatment - machining" is established to meet customers' customized needs. With the increasing reliability requirements of high-end equipment for materials, the company is stepping up R&D investment in single crystal alloys and high-temperature alloy powders for 3D printing, etc., and is expected to form a full-form product matrix covering "casting + deformation + powder metallurgy" by 2027, providing stronger support for the replacement of imported materials with domestic ones.