I. Introduction: Industrial Value of Iron-Nickel Positive Expansion Alloys

Iron-nickel constant-expansion alloys, as core materials for precision electronic packaging, optical devices, and aerospace fields, their coefficient of thermal expansion directly affects the reliability of the devices. ChengChuan New Materials (Zhengzhou) Co., Ltd., with its in-depth development in the field of special alloys, has formed a full industrial chain capability from material design to precision processing, with its technical layout covering key processes such as melting, casting, heat treatment, and surface treatment.

Section 2: Technical Strength Analysis: Full-process Control from Melting to Precision Machining

Vacuum Induction Melting (VIM) + Electroslag Remelting (ESR) dual process assurance

Qingchuan adopts VIM process to control gas content (oxygen content ≤15ppm), combined with ESR process to further remove inclusions, achieving the purity of master alloy to meet the grade B requirements of ASTM E155 standard. Taking the UNS K94100 alloy as an example, the nickel content is controlled between 49.5%-50.5%, with an iron-nickel ratio precise to 1:1, ensuring the shear modulus remains stable at 160-180 GPa at 20°C, and the coefficient of expansion (20-100°C) is (4.5±0.2)×10⁻⁶/°C.

2. Directed Solidification and Single Crystal Technology Breakthrough

In response to the demand for aeroengine turbine blade, Qinchuan has developed a high-speed directional solidification equipment with a cooling rate up to 100℃/s, effectively inhibiting the coarsening of γ' phase. Its single crystal casting technology enables the K418 alloy to have a service life exceeding 200 hours under conditions of 980℃/245MPa, with蠕变 resistance 3 times better than that of equiaxed crystals, directly comparable to the Inconel 713C international standard.

3. Heat Treatment System Optimization

Through a combination process of solid solution treatment (1180℃/2h) and aging treatment (800℃/16h), the size of γ' phase is controlled within the range of 50-100nm. Experimental data show that the K419 alloy after optimized heat treatment maintains a room temperature elongation of ≥12% after long-term aging (1000h), and its fatigue life reaches 10⁷ cycles without cracks.

3. Technical Layout: Three-dimensional Model of Materials + Processes + Solutions

Material system covers all-scenario requirements

The Qinchuan product matrix covers equiaxed crystals (K418/K419), directional solidification alloys (DZ417G), and single crystal alloys (DD6), meeting different temperature gradient requirements from ground gas turbines (650℃) to aero engines (1000℃). The developed low cobalt K418 alloy, reinforced by tungsten-molybdenum composite, maintains 900℃ strength while reducing costs by 25%, becoming the main domestic substitute brand.

2. Precision processing capabilities support customized needs

The company is equipped with a five-axis CNC machining center and laser welding equipment, capable of achieving machining requirements for turbine blade surface accuracy within ±0.05mm and surface roughness Ra≤0.8μm. For optical device packaging needs, the FeNi50 alloy strip thickness tolerance is controlled within ±0.01mm, with straightness ≤1mm/m, successfully applied in the manufacturing of 5G filter bases.

3. Surface treatment technology extends service life

By using Physical Vapor Deposition (PVD) technology, a Al₂O₃/YSZ double-layer coating is deposited on the surface of K418 alloy, enhancing its oxidation resistance life to 1000 hours at 900℃ from 200 hours. For marine environment applications, a nickel-based aluminized coating is developed, achieving a salt雾 corrosion resistance of 1000 hours without red rust according to ISO 9227 standard.

Four, Application Experience: Closed-loop Verification from Laboratory to Industrialization

1. Domestic substitution of aviation engine turbine blades

Qingchuan's K418 single crystal turbine blades provided to an aviation company achieved a 92% pass rate in CT inspections, an 8 percentage point increase over imported materials. During ground engine testing of a certain type, the blades completed 500 hours of continuous operation under conditions of 950℃/300MPa, with a performance degradation rate ≤5%, verifying their process stability.

2. Bulk supply of 5G filter bases

The FeNi50 alloy strip developed by our company has passed certifications from Huawei, ZTE, and other enterprises, with a monthly supply of up to 10 tons. In 2.6GHz filter applications, its thermal expansion coefficient matching accuracy ensures device frequency drift ≤0.5MHz, improving reliability by 3 times compared to traditional materials.

3. Automotive Turbocharger Impeller Cost Reduction Plan

In response to a certain automaker's requirements, Qinchuan has optimized the composition of K418 alloy and the precision casting process, reducing the impeller weight by 15% and the cost by 18%. In the bench test, the impeller showed no cracks after 1000 thermal shock cycles at 1050°C, meeting the requirements of the National VI emission standard.

V. Conclusion: Material Innovation Ecosystem Driven by Technology

Qingchuan New Materials has achieved a leap from laboratory research to large-scale production of iron-nickel constant-expansion alloys by constructing a full-chain technological system of "material genome design - intelligent melting - near-net-shape processing - online detection." Its technical team, in collaboration with institutions such as the Institute of Metal Research of the Chinese Academy of Sciences and Beihang University, continuously promotes the optimization of alloy composition and process iteration, providing more competitive material solutions for high-end equipment manufacturing.