The aerospace field has extremely strict requirements for material performance. Materials not only need to have high strength and high toughness, but also need to maintain stable performance under extreme temperature and pressure environments. As the core equipment for material heat treatment, vacuum furnaces have become a key tool for regulating the performance of aerospace materials, thanks to their advantages of oxidization-free heating, precise temperature control and clean environment. Taicang Huarui Vacuum Furnace Industry Co., Ltd. has been deeply engaged in vacuum heat treatment technology. The vacuum furnace series products it has developed have performed outstandingly in the processing of key aerospace materials such as titanium alloys, superalloys, and composite materials, providing a reliable guarantee for the improvement of material performance.
Application of vacuum heat treatment in titanium alloy materials
Titanium alloys, due to their high strength, low density and strong corrosion resistance, have become materials for structural components of aerospace vehicles. However, they have high chemical reactivity and are prone to react with oxygen and nitrogen at high temperatures, leading to performance deterioration. The non-oxidizing environment of vacuum furnaces has become an ideal choice for the heat treatment of titanium alloys. In the vacuum annealing treatment of titanium alloys, Huarui vacuum furnaces effectively eliminate material processing stress and avoid surface contamination by precisely controlling the vacuum degree (usually ≤10⁻³Pa) and heating rate. For instance, the TC4 titanium alloy aircraft landing gear forgings have considerable internal stress after rolling. After undergoing 920℃ vacuum annealing in the Huarui vacuum furnace (holding for 2 hours and cooling with the furnace), the stress relief rate exceeds 80%, and the elongation of the material increases from 10% to 15%, meeting the plasticity requirements of the landing gear under impact loads. Slow cooling in a vacuum environment (50℃/h) reduces temperature difference stress, and the deformation of the forging is controlled within 0.1mm/m, allowing it to directly enter the finishing process without subsequent straightening. Vacuum quenching and aging treatment of titanium alloys are used to enhance their strength. When treating the Ti-6Al-4V alloy in the Huarui vacuum quenching furnace, it is first held at 850℃ in a vacuum environment for 1 hour (to ensure uniform transformation of the β phase), then 0.3MPa argon gas is introduced for rapid cooling (cooling rate 15℃/s), and finally subjected to aging treatment at 500℃ for 4 hours. The tensile strength of the treated alloy has been increased from 900MPa to 1100MPa, the hardness has reached HRC38-40, and the fatigue life has been extended by 30%, fully meeting the usage requirements of aero engine fan blades. After a certain aviation manufacturing enterprise adopted this process, the qualification rate of blades increased from 75% to 95%, significantly reducing production costs. Taicang Huarui Vacuum Furnace Industry Co., Ltd., in light of the characteristics of titanium alloys, selects graphite and ceramics with low gas release rates for the furnace body materials to reduce the contamination of titanium alloys by gases inside the furnace at high temperatures. At the same time, optimize the layout of heating elements to keep the temperature uniformity inside the furnace within ±3℃, ensuring the performance consistency of all parts of large titanium alloy components (such as the machine body frame).
Application of vacuum treatment process for superalloys
Superalloys are the core materials for high-temperature components such as combustion chambers and turbine blades in aero engines. They need to maintain high strength and oxidation resistance in an environment of 600-1000℃. The performance of superalloys depends on precise vacuum heat treatment processes. The Huarui vacuum furnace precisely regulates the microstructure of superalloys by controlling the heating temperature, holding time and cooling rate. In the vacuum solution treatment of nickel-based superalloys, the high-temperature performance advantages of Huarui vacuum furnaces are fully demonstrated. When processing Inconel 718 alloy, the furnace temperature should be stabilized at 1120℃ (±2℃), held for 2 hours to fully dissolve the γ "phase, and then nitrogen gas should be introduced for rapid cooling (cooling rate ≥50℃/s) to inhibit the precipitation of harmful phases. The yield strength of the treated alloy remains above 800MPa at 650℃, making it suitable for the manufacturing of engine turbine discs. Test data from a certain aero engine enterprise shows that the endurance strength (650℃, 1000 hours) of the turbine discs treated by Huarui vacuum furnace is 15% higher than that treated by traditional air furnace, meeting the requirements for long-term operation of engines. The vacuum aluminizing process of cobalt-based superalloys is used to enhance their oxidation resistance. In a vacuum environment of 10⁻¹Pa, the Huarui vacuum furnace heats the alloy and the aluminum source to 950℃ and holds it for 4 hours to allow aluminum atoms to diffuse to the surface layer of the alloy, forming a continuous Al₂O₃ oxide film. This treatment reduces the oxidation rate of the alloy by 60% at 1000℃, making it suitable for high-temperature components such as combustion chambers and flame tubes. The multi-zone temperature control system of Huarui vacuum furnace ensures uniform temperature inside the furnace. The thickness difference of the aluminized layer at different parts of the flame cylinder is ≤5μm, avoiding early failure caused by local oxidation. For large components of high-temperature alloys (such as engine casings), Huarui vacuum furnaces have designed large-sized furnace chambers and dedicated fixtures to ensure uniform heating of the components during the heat treatment process. A certain casing manufacturing enterprise used the Huarui vacuum furnace to treat a casing with a diameter of 1.5 meters. The test results showed that the radial temperature difference was ≤3℃. After heat treatment, the roundness error of the casing was controlled within 0.05mm, meeting the requirements for precise assembly with other components.
Vacuum forming and curing applications of composite materials
Composite materials in the aerospace field (such as carbon fiber reinforced resin matrix composites and metal matrix composites) have strict requirements for the molding environment. The vacuum environment and pressure control capability of vacuum furnaces provide crucial support for the densification and performance optimization of composite materials. Vacuum curing of carbon fiber reinforced resin matrix composites is a typical application scenario of Huarui vacuum furnaces. During the curing process, the Huarui vacuum furnace first evacuates the furnace chamber to a vacuum (≤10⁻²Pa) to eliminate air bubbles in the material. Then, it heats up to 180℃ according to the preset curve (2℃/min), while applying a pressure of 0.6MPa (achieved through inert gas) to ensure that the resin flows fully and wets the fibers. The interlayer bonding strength of the cured composite material is increased by 40%, and the porosity is controlled below 1%, making it suitable for load-bearing structures such as aircraft wings and tails. After a certain aircraft manufacturer adopted this process, the fatigue life of the composite material wing was extended by 25%, and its weight was reduced by 30% compared with the aluminum alloy structure, significantly improving the fuel efficiency of the aircraft. The vacuum sintering of metal matrix composites (such as aluminum-based silicon carbide composites) relies on the high-temperature and high-pressure environment of Huarui vacuum furnaces. During the processing, when the furnace temperature rises to 600℃, a vacuum is maintained to remove the volatile substances in the material. Then, argon gas is filled to 0.5MPa, and the temperature is raised to 560℃ and maintained for 3 hours to promote interfacial reactions and form a strong bond. The tensile strength of the treated composite material reaches 600MPa, and the coefficient of thermal expansion is reduced to 7×10⁻⁶/℃, making it suitable for high-precision components such as antenna brackets of spacecraft. The precise temperature control capability of Huarui vacuum furnace ensures that there is no overburning of composite materials during the sintering process. The silicon carbide particles are evenly distributed, avoiding cracking caused by local stress concentration. For the irregular components of composite materials (such as engine air intakes), Huarui vacuum furnaces are equipped with flexible tooling systems, ensuring uniform pressure on all parts of the components through adjustable pressure heads. After vacuum curing, the surface flatness of the composite material air inlet processed by a certain aerospace enterprise reached Ra1.6μm, meeting the aerodynamic shape requirements. It can be installed and used without subsequent grinding.
Vacuum heat treatment of precision bearings and transmission components
Precision bearings, gears and other transmission components of aerospace vehicles require extremely high dimensional accuracy and wear resistance. The non-oxidation quenching process in vacuum furnaces can effectively enhance the performance stability and service life of these components. In the vacuum quenching treatment of bearing steel (such as M50 high-speed steel), the Huarui vacuum oil quenching furnace demonstrates unique advantages. The treatment process is as follows: Heat to 1040℃ under a vacuum of 10⁻²Pa, hold for 1 hour to fully dissolve the carbides, then cool in quenching oil at 80℃ (cooling rate 60℃/s), and finally temper three times at 540℃. The hardness of the treated bearing steel reaches HRC62-64, and its contact fatigue life L10 (90% survival rate) exceeds 1000 hours, making it suitable for the main shaft bearings of helicopter transmission systems. The oil temperature control accuracy (±2℃) of Huarui vacuum oil quenching furnace ensures the uniform cooling of bearing rollers. The hardness difference of each part of the rollers is ≤1HRC, avoiding the early wear caused by uneven hardness in traditional quenching. The vacuum carburizing + quenching process for carburizing bearing steel used in aviation gears demonstrates the multi-functionality of Huarui vacuum furnaces. First, a mixture of propane and nitrogen (with a partial pressure ratio of 1:5) is introduced into the vacuum furnace, and carburized at 930℃ for 4 hours. Then, the temperature is directly raised to 850℃ for austenitizing, and 0.5MPa nitrogen is introduced for cooling. This integrated "carburizing - quenching" treatment reduces the transfer time of parts, avoids secondary oxidation, and ensures uniform depth of the carburized layer on gears (1.2±0.1mm), with a surface hardness of HRC60-62 and a core hardness of HRC35-40, meeting the dual requirements of wear resistance on the tooth surface and impact resistance on the tooth core. After a certain aviation gearbox manufacturer adopted this process, the operating noise of the gears was reduced by 5 decibels, and the service life was extended to 8,000 hours, which was 50% longer than that of the traditional process.
Vacuum treatment application of special functional materials
Special functional materials in the aerospace field (such as magnetic materials and stealth materials) have unique requirements for microstructure and surface properties. Huarui vacuum furnaces meet the special processing needs of these materials through customized process design. The performance of samarium cobalt permanent magnetic materials used in spacecraft attitude control systems is closely related to the magnetic domain structure. When Huarui vacuum furnace processes samarium cobalt alloy, it adopts the "vacuum sintering + aging" process: vacuum sintering at 1150℃ (10⁻³Pa) densifies the alloy, and then aging is carried out in stages at 800℃ and 600℃. By regulating the size and distribution of the precipitated phase, the coercives force of the material is increased to over 20kOe. The vacuum environment prevents magnetic powder oxidation, and the magnetic energy product (BH) max of the material is maintained at 25MGOe, ensuring the precise control of the attitude control system. Vacuum heat treatment of radar stealth materials (such as ferrite coatings) is used to optimize their electromagnetic parameters. The Huarui vacuum furnace annealing the coating in a vacuum environment of 450℃ removes organic binders and promotes the uniform growth of ferrite grains, making the dielectric constant and magnetic permeability of the coating match the design requirements, and reducing the radar wave reflectivity by more than 15dB. The low-temperature control accuracy (±1℃) of Huarui vacuum furnace ensures that the coating will not change in composition due to overheating, meeting the stability requirements of stealth performance. In response to the small-batch and multi-variety processing requirements of these special materials, Huarui vacuum Furnace has designed a rapid production change system. The time for changing the furnace fixtures has been shortened to 30 minutes, and different process parameters can be stored and called up. After a certain aerospace materials research institute adopted this system, the research and development cycle of new materials was shortened by 40%, accelerating the engineering application of special functional materials.
Process innovation and equipment technology upgrading
Taicang Huarui Vacuum Furnace Industry Co., Ltd. continuously innovates its processes and upgrades its equipment technology in response to the processing characteristics of aerospace materials. By optimizing the vacuum system, temperature control accuracy and automation level, it enhances the stability and efficiency of material processing. In terms of vacuum system optimization, Huarui vacuum furnaces adopt a combination of "multi-stage pump sets + molecular pumps", enabling rapid switching from rough vacuum to high vacuum (pumping from atmospheric pressure to 10⁻⁴Pa within 30 minutes), reducing the oxidation risk of materials during the medium vacuum stage. For instance, when processing titanium alloys, rapid vacuuming enables the material to enter a high vacuum state below 500℃, preventing the formation of the α-case layer (surface embrittlement layer). The layer depth is controlled within 5μm, thereby enhancing the fatigue performance of the material. The upgrade of the temperature control system is reflected in the application of multi-sensor fusion and intelligent algorithms. The Huarui vacuum furnace is equipped with 12-point thermocouples in the furnace chamber to monitor the temperature of different areas in real time. The heating power is dynamically adjusted through the PID self-tuning algorithm, improving the temperature uniformity inside the furnace to ±2℃. Tests conducted by a certain engine blade manufacturer show that after adopting this temperature control system, the temperature difference between the blade tenon and the blade body drops from 5℃ to 2℃. The deformation of the blade after heat treatment is reduced by 30%, the allowance for fine machining is decreased, and the production cost drops accordingly. The automation and data traceability functions meet the quality control requirements in the aerospace field. The MES system equipped on Huarui vacuum furnaces can automatically record the process parameters (temperature, vacuum degree, pressure, etc.) of each furnace, form a complete heat treatment curve, and support data upload and traceability. Meanwhile, the system is equipped with an anti-tampering function for process parameters, ensuring the authenticity and traceability of the data, and meeting the quality system certification requirements of the aerospace industry. A certain aircraft manufacturer has achieved digital management of the entire material heat treatment process through this system. The time for tracing quality issues has been reduced from 2 hours to 10 minutes, significantly enhancing the efficiency of quality management.
The application of Huarui vacuum furnaces in the processing of aerospace materials not only resolves issues such as material oxidation and uneven performance in traditional heat treatment processes, but also provides the possibility of maximizing material performance through precise process control and equipment innovation. The in-depth cooperation between Taicang Huarui Vacuum Furnace Industry Co., Ltd. and aerospace enterprises has promoted the coordinated development of vacuum heat treatment technology and material processes, providing a solid material guarantee for the lightweight, high reliability and long service life of aircraft. With the continuous advancement of aerospace technology, the technical requirements for Huarui vacuum furnaces will continue to rise. Its technological accumulation in areas such as high temperature, high vacuum, and precise temperature control will surely play a more significant role in future aerospace exploration.
