Introduction: Technical Value of Iron-Nickel Determinate Expansion Sealing Alloy

Iron-nickel fixed expansion sealing alloys, by precisely controlling the nickel content, achieve precise matching with the thermal expansion coefficients of materials such as glass and ceramics, and have become core materials in fields such as electric vacuum devices, semiconductor packaging, and aerospace sensors. Qinchuan New Materials (Zhengzhou) Co., Ltd. has formed a unique technical advantage in this field with its technical accumulation and process innovation capabilities.

Technical layout: Full-process control from melting to shaping

Qingchuan New Materials adoptsVacuum Induction Melting (VIM) + Electroslag Remelting (ESR) / Vacuum Arc Remelting (VAR)Combined process, the gas content is controlled at ≤0.001% level through a three-level purification system, ensuring the purity of the master alloy meets aerospace standards. For example, the nickel content in the 4J42 alloy produced is strictly controlled within the range of 41.5%-42.5%, with a component design of carbon ≤0.03% and manganese ≤0.50%, resulting in a stable thermal expansion coefficient of (10.5-11.5)×10⁻⁶/℃ within the temperature range of 20-400℃, with a matching degree of 98.7% with DM-308 soft glass.

In the molding process, Qinchuan breaks through the traditional forging limitations, throughInvestment Casting + Hot Isostatic Pressing (HIP)Achieving near-net shaping of complex structural components. Taking the turbine blade of an aeronautical engine as an example, it adopts directional solidification technology to control the size of the γ' strengthening phase within the range of 50-100nm, which enhances the alloy's tensile strength at 900℃ to 350MPa, a 22% increase compared to traditional processes.

Application Case: Breakthrough in Domestic Production of High-end Equipment

In the semiconductor packaging field, the 4J50 alloy lead frame material developed by Qinchuan has passed rigorous tests by a spacecraft-grade chip manufacturer. After being treated with hydrogen annealing at 900℃±20℃, the surface roughness Ra is ≤0.8μm, and the leakage rate when co-sintered with alumina ceramics is below 1×10⁻¹¹ Pa·m³/s, meeting the requirements of the GJB 548B-2005 military electronic component environmental test. Actual installation data shows that the power module using this material maintains an interface bonding strength of 92.3% after 1000 cycles of temperature cycling from -60℃ to 450℃.

In the aerospace field, Qinchuan's 4J42 alloy shell developed for a satellite sensor model has significantly improved high-temperature stability by optimizing cobalt content to 0.5%. In ground simulation tests, the material maintained grain size within ASTM E112 standard 6-8 after continuous operation at 650℃ for 2000 hours, with a tensile strength retention rate of 89%, and a cost reduction of 31% compared to imported materials.

Technical Parameters and Quality Control

Qingchuan New Materials has established a quality control system covering the entire production cycle.

• Chemical Composition ControlThe content is already in English encoding, so no translation is needed: : Using ICP-AES spectral analysis, the fluctuation of key elements such as nickel and cobalt is controlled within ±0.05%.
• Organizational Stability TestingThrough the combined use of metallographic microscope and SEM-EDS, ensure the content of austenite phase is ≥99.5%.
• Performance Traceability SystemEach batch of products comes with a material certificate, ultrasonic flaw detection report, and heat treatment curve record.

The 4J42 alloy sheet produced by us has a thickness tolerance of ±0.05mm and a flatness of ≤1mm/m, which can be directly used for high-precision stamping, reducing subsequent processing allowance by over 30%.

Conclusion: Technology-driven material innovation

Qingchuan New Materials has formed a complete product line covering series of alloys such as 4J42, 4J50, GH4169 through continuous technological iteration. Its "material + process + solution" business model not only solves the dependence of high-end equipment on imported materials but also shortens the delivery cycle to within 15 days through localized services. With the rapid development of intelligent manufacturing and the new energy field, the technical demand for iron-nickel fixed expansion sealing alloys will continue to grow, and Qingchuan New Materials' technical practice provides an reproducible domestication path for the industry.