Vacuum heat treatment furnace: technical analysis, application expansion and industry prospects

In the field of modern industrial manufacturing materials science research, heat treatment process is a key link in determining material properties. The traditional heat treatment method is limited by the interference of the atmospheric environment, and it is difficult to meet the stringent requirements of high-end materials for performance. Vacuum heat treatment furnace by virtue of the unique advantages of material heat treatment in a vacuum environment, effectively avoiding material oxidation, decarburization and other issues, can significantly enhance the comprehensive performance of the material, and become the core equipment to promote the manufacturing industry to the high-end, precision development. Ltd. plows deep into the field of vacuum heat treatment technology, in the vacuum heat treatment furnace R & D and manufacturing of fruitful, innovative technology and quality products for the development of the industry to provide a strong boost.

First, the working principle and structural composition of the vacuum heat treatment furnace

(A) the core working principle

The working principle of the vacuum heat treatment furnace is based on the influence of the vacuum environment on the physical and chemical changes in the material. In the conventional atmospheric environment, the material in the heating process will be in the air with oxygen, water vapor, nitrogen and other chemical reactions, resulting in surface oxidation, decarburization, nitriding and other phenomena, not only affecting the appearance of the material quality, but also reduce the mechanical properties of the material and service life. Vacuum heat treatment furnace through the vacuum system will be the furnace air extraction, so that the furnace air pressure down to a very low level, effectively reducing the probability of contact between gas molecules and the surface of the material, to create a relatively pure processing environment. Heat treatment in a vacuum environment, the material surface and internal adsorption of gas molecules are more likely to escape, to avoid the occurrence of oxidation, decarburization and other adverse reactions. At the same time, the vacuum environment can also change the phase transition temperature, diffusion rate and other physical properties of the material, providing unique conditions for material heat treatment. For example, in the vacuum quenching process, due to the absence of the obstruction of the oxide skin, the quenching medium can be more uniformly in contact with the material surface, so that the material obtains a more uniform organization and properties; in the vacuum annealing, tempering and other processes, the vacuum environment helps to eliminate the stress within the material, improve the microstructure of the material, and improve the toughness and plasticity of the material. In addition, by filling specific gases (such as inert gases, reactive gases, etc.) into the vacuum heat treatment furnace, it can also realize the surface treatment processes such as gas carburizing and nitriding to further enhance the surface properties of the material.

(B) Structure

Vacuum heat treatment furnace mainly consists of furnace body, vacuum system, heating system, gas control system, cooling system, control system and safety protection devices and other components. Furnace body is the main structure of the vacuum heat treatment furnace, usually made of high-strength double-layer metal, filled with high-temperature-resistant insulation materials, such as ceramic fiber, rock wool, etc., in order to reduce heat loss and improve the efficiency of energy use. The sealing performance of the furnace body is crucial to ensure that no leakage occurs under vacuum and high temperature environments by means of specially designed vacuum sealing structures and high-performance sealing materials (e.g. Viton seals, metal sealing gaskets, etc.). The interior of the furnace chamber is equipped with a sample-carrying platform, which can be custom-designed for workpieces of different sizes and weights, making it easy to load and fix materials. Part of the furnace is also equipped with an observation window, which is made of special glass material resistant to high temperature and high pressure, making it easy for the operator to observe the processing status of the workpieces in the furnace in real time. Vacuum system is the key component to realize the vacuum environment, which generally consists of multi-stage vacuum pumps such as mechanical pump, Roots pump, molecular pump, etc., combined with vacuum piping, vacuum valves and vacuum measuring instruments. The mechanical pump is used as a pre-stage pump for rough pumping to quickly reduce the air pressure inside the furnace; the Roots pump plays a pressurizing role between the mechanical pump and the molecular pump to improve the pumping efficiency; the molecular pump is used to obtain a high vacuum or ultra-high vacuum environment. Vacuum valves control the flow of gas and on-off, vacuum measuring instruments (such as Pirani vacuum gauge, ionization vacuum gauge) real-time monitoring of the furnace vacuum, and feedback data to the control system to ensure that the furnace vacuum environment to meet the process requirements.

The heating system utilizes highly efficient heating elements. Depending on the operating temperature and process requirements, common heating elements include resistance wires, silicon molybdenum rods, tungsten wires, etc. The heating elements are evenly distributed around or at the bottom of the furnace chamber to ensure temperature uniformity. The heating elements are evenly distributed around or at the bottom of the furnace chamber to ensure the temperature uniformity in the furnace chamber through a reasonable layout design. The heating system is equipped with high-precision temperature sensors, such as thermocouples and RTDs, to monitor the temperature in the furnace in real time and transmit the temperature signal to the control system. The control system accurately adjusts the power of the heating element according to the preset heating curve to realize precise control of the temperature, and the temperature control accuracy is usually up to ±1℃ to meet the stringent temperature requirements for heat treatment of different materials. The gas control system is used to charge or discharge specific gases into the furnace to realize different heat treatment processes. The system consists of gas storage tanks, pressure reducing valves, flow meters, gas mixing devices and other components. The gas storage tank is used to store different kinds of gases (e.g. nitrogen, argon, hydrogen, etc.); the pressure reducing valve regulates the high-pressure gas to the appropriate pressure; the flow meter precisely controls the gas flow; the gas mixing device can mix different gases proportionally according to the process requirements. Through the gas control system, it can realize a variety of heat treatment processes such as vacuum protection heating, gas carburizing, nitriding and so on. Cooling system is used to cool the workpiece after heat treatment, and also to cool and protect the furnace body and some key parts. The cooling system is generally air-cooled, water-cooled or a combination of air-cooled and water-cooled. For the cooling of workpiece, it can be air-cooled by filling high-pressure gas (such as nitrogen) into the furnace, or oil-cooled or water-cooled; for the cooling of the furnace body and parts, circulating cooling water or cooling fan is used to prevent the equipment from being damaged due to overheating and to ensure the stable operation of the equipment. The control system is the “brain” of the vacuum heat treatment furnace, which usually adopts programmable logic controller (PLC) or computer control system with man-machine interface (such as touch screen or computer terminal).

The operator can conveniently set process parameters such as vacuum degree, heating temperature, heating rate, holding time, gas flow rate, etc. through the interface. The control system can automatically coordinate the work of the vacuum system, heating system, gas control system and cooling system to realize the automatic operation of the equipment. In the operation process, it collects and records the process data in real time, and analyzes and processes them. When abnormal situations occur (such as over-temperature, vacuum abnormality, gas leakage, etc.), it will immediately issue an alarm and take corresponding protective measures, such as cutting off the heating power supply, closing the gas valve, etc., to ensure the safety of the equipment and the workpiece. Safety protection device is an important part to ensure the normal operation of the vacuum heat treatment furnace and personnel safety, in addition to the basic over-temperature protection, over-voltage protection, leakage protection, short-circuit protection, but also equipped with gas leakage alarm device, emergency shutdown button and so on. For example, when the furnace temperature exceeds the set safety value, the over-temperature protection device automatically cut off the heating power supply; if the vacuum system or the gas control system is abnormal resulting in high pressure, the overpressure protection device starts to release the pressure; the gas leakage alarm device can real-time monitoring of gas leakage in the furnace, once the leakage is detected, the alarm will be issued immediately and emergency measures will be taken to prevent the occurrence of safety accidents.

Second, the application of vacuum heat treatment furnace

(A) aerospace field

Aerospace field of metal materials performance requirements are extremely harsh, vacuum heat treatment furnace plays an indispensable role in this field. In the manufacture of aircraft engines, high temperature alloy blades, turbine disks and other core components need to have excellent high temperature strength, oxidation resistance and fatigue properties. Through the vacuum heat treatment furnace for quenching, tempering and other processes, can avoid material oxidation and decarburization in the heating and cooling process, precise control of the cooling rate and tissue transformation, so that the material to obtain the ideal organizational structure, and significantly improve the mechanical properties of the components, to ensure that the aircraft engine at high temperatures, high pressures, high rotation speeds, and other extreme conditions of stable and reliable operation. Meanwhile, for the structural parts of spacecraft, such as titanium alloy frame, aluminum alloy skin, etc., vacuum heat treatment can eliminate processing stress, refine the grain, improve the plasticity and toughness of the material, enhance the deformation resistance and reliability of the parts, and safeguard the safe operation of spacecraft in the space environment.

(B) Mold manufacturing industry

Mold manufacturing requires high hardness, wear resistance, toughness and dimensional accuracy of the material. Vacuum heat treatment furnace can be used for mold steel quenching, tempering, annealing and other heat treatment processes, effectively avoiding oxidation and decarburization of the mold surface, to ensure that the mold surface quality and dimensional accuracy. Through precise control of heat treatment process parameters, can make the mold to obtain uniform organizational structure and good comprehensive mechanical properties, improve the service life of the mold and molding accuracy. For example, in the injection mold, die-casting mold manufacturing, after vacuum heat treatment of the mold, its surface hardness is higher, better wear resistance, can withstand frequent opening and closing of the mold and high temperature and high pressure molding process, reduce mold wear and deformation, reduce production costs, improve production efficiency. In addition, vacuum heat treatment can also improve the internal stress distribution of the mold, reduce the risk of mold cracking in the process of use.

(C) automobile manufacturing field

Automobile manufacturing industry in order to improve the performance and reliability of parts and components, the heat treatment process of metal materials requirements continue to improve. Vacuum heat treatment furnace can be used to deal with key components of automobile engines, such as crankshafts, connecting rods, gears, etc., through vacuum quenching, tempering and other processes to improve the internal organization of the material, improve the strength, toughness and fatigue life of the parts, reduce the probability of failure due to material failure, enhance the overall performance and safety of the car. For automotive lightweight parts, such as aluminum alloy wheels, magnesium alloy shells, vacuum heat treatment can optimize the grain structure of the material, enhance the mechanical properties of the parts, reduce the weight of the car at the same time to ensure its load-bearing capacity and reliability, in line with the development trend of the automotive industry energy saving and emission reduction. In addition, vacuum heat treatment can also be used for surface treatment of automotive parts, such as gas carburizing, nitriding, etc., to improve the surface hardness and wear resistance of parts.

(D) the field of electronic and electrical appliances

In the field of electronics and electrical appliances, vacuum heat treatment furnace is mainly used for the processing of electronic materials and packaging of components. In the semiconductor chip manufacturing, the chip in the manufacturing process requires multiple heat treatment processes, such as annealing, diffusion, etc.. Vacuum heat treatment furnace can provide precise temperature control and clean vacuum environment to avoid contamination of the chip in the heat treatment process and improve the performance and reliability of the chip. For example, when annealing a chip, the vacuum environment can eliminate the stress inside the chip, improve the crystal structure, and improve the electrical performance of the chip. For electronic ceramic devices, such as multilayer ceramic capacitors (MLCC), ceramic filters, etc., vacuum heat treatment can be used for ceramic billet sintering and component encapsulation, so as to make ceramic grains grow uniformly, and to improve the dielectric properties and mechanical strength of ceramics. In addition, vacuum heat treatment can also be used for welding and encapsulation of electronic components, to prevent oxidation of the welded parts, improve the quality of welding and encapsulation of the sealing.

(E) the field of scientific research experiments

In scientific research experiments, vacuum heat treatment furnace for materials science research provides an important experimental platform. Researchers can use the vacuum heat treatment furnace to study different metal materials, ceramic materials, composite materials in a vacuum and different gas atmosphere of the organization of the evolution of the law, the mechanism of phase transition and property changes, to explore new heat treatment processes and material formulations. Through precise control of vacuum, heating temperature, cooling rate and other process parameters, simulate a variety of actual working conditions, for the research and development of new materials and performance optimization of existing materials to provide experimental data and theoretical basis. For example, to study the martensitic transformation behavior of new alloy materials in the vacuum quenching process, to explore new ways to improve the strength and toughness of alloys; to study the densification mechanism of ceramic materials in the vacuum sintering process, to develop high-performance ceramic materials. In addition, the vacuum heat treatment furnace can also be used to study the performance changes of materials in extreme environments, providing support for the development of technology in aerospace, energy and other fields.

III. Technical Advantages and Contributions of Principal Vacuum Technology (Jiangsu) Co.

(A) Technical innovation ability

In the process of research and development of vacuum heat treatment furnace, Principal Vacuum Technology (Jiangsu) Co., Ltd. has always insisted on technological innovation and constantly broken through the technological bottleneck in the industry. In terms of vacuum system design, the company's R&D team has significantly improved the pumping efficiency and vacuum stability by optimizing the combination of vacuum pumps and the layout of vacuum pipelines, and adopting new vacuum sealing materials and structures, which enables the equipment to reach a high vacuum or ultra-high vacuum environment in a shorter time and effectively reduces the leakage rate, thus providing purer vacuum conditions for the heat treatment of materials. At the same time, the company has also developed an intelligent vacuum control system, which can automatically adjust the vacuum level according to different process requirements, improving the adaptability and flexibility of the equipment. In terms of heating system innovation, the company adopts new heating materials and intelligent temperature control algorithm. The new heating material has the advantages of high heating efficiency, high temperature resistance, long life, etc., which can quickly and evenly heat the furnace chamber.

Intelligent temperature control algorithm combined with high-precision temperature sensor realizes accurate control and fast response to temperature, and can flexibly adjust the temperature change curve according to different materials and process requirements, ensuring the accuracy and stability of the temperature in the heat treatment process. In addition, the company also applies infrared temperature measurement technology to the vacuum heat treatment furnace, realizing the non-contact measurement of the surface temperature of the workpiece and improving the precision and reliability of temperature measurement. In terms of gas control system, the company has developed high-precision gas flow and pressure control technology, which can accurately control the flow, pressure and composition of the gas to meet the strict requirements of different heat treatment processes on the gas atmosphere. Through the gas mixing device and intelligent control algorithm, the precise proportioning and dynamic adjustment of multiple gases can be realized, which provides reliable technical support for surface treatment processes such as gas carburizing and nitriding. Meanwhile, the company has also developed a gas recycling system, which can recycle, purify and reuse the gases generated in the heat treatment process, reducing production costs and environmental pollution.

(II) Product customization service

Principal Vacuum Technology takes into full consideration the diversified needs of different industries and customers for vacuum heat treatment furnaces, and provides a full range of customized product solutions. The company's technical staff in-depth understanding of the customer's production process, workpiece characteristics and special requirements, from the overall structural design of the equipment, functional module configuration to process parameter settings for personalized customization. For aerospace and other high-end manufacturing enterprises, according to their high-precision requirements for heat treatment of parts and components, we customize vacuum heat treatment furnaces with ultra-high vacuum, precise temperature control and strict gas atmosphere control, and are equipped with automated workpiece loading and transfer systems to meet the needs of large-scale, high-precision production. Meanwhile, for the special heat treatment process requirements of aerospace materials, we develop customized process software to achieve precise control and optimization of the heat treatment process. For scientific research institutions, according to their research direction and experimental needs, we design flexible adjustment range of process parameters, rich data acquisition functions and convenient sample replacement devices, which are convenient for researchers to carry out experimental research under different conditions. In addition, the company can also provide customers with special size, special structure of the vacuum heat treatment furnace design to meet the individual needs of customers.

(III) Perfect after-sales service system

Principal Vacuum Technology attaches great importance to after-sales service and has established a perfect after-sales service system. The company has a professional after-sales service team, covering equipment installation and commissioning, operator training, equipment maintenance and fault repair and other aspects. In the stage of equipment installation and commissioning, technical personnel visit the customer site to carry out equipment installation, commissioning and test run to ensure that the equipment performance indexes meet the requirements, and systematic training of the customer's operators, so that they are proficient in the operation of the equipment, routine maintenance and simple troubleshooting skills. In the process of equipment use, the after-sales service team regularly visits and maintains the equipment, finds and solves potential problems in time, and prolongs the service life of the equipment. When equipment failure occurs, the after-sales service team can respond quickly, through remote diagnosis or send technicians to the scene for maintenance, to restore normal operation of the equipment in the shortest possible time to minimize the impact of equipment downtime on the customer's production and scientific research work. In addition, the company also provides customers with equipment upgrading services, according to technological development and changes in customer demand, the performance of the equipment to improve and expand the function, so that customers can always use the advanced, reliable vacuum heat treatment furnace equipment. At the same time, the company has established a customer service database, tracking management of customer equipment use, maintenance records, etc., to provide customers with more personalized and professional after-sales service.

Fourth, the vacuum heat treatment furnace market status and development trend

(i) the current market situation

At present, with the rapid development of aerospace, automobile manufacturing, electronics and electrical appliances, mold manufacturing and other industries, as well as materials science and technology continues to progress, the market demand for vacuum heat treatment furnace continues to grow. There are many suppliers of vacuum heat treatment furnace in the market, and the competition is relatively fierce. Some international veteran enterprises with its long-term technical accumulation, advanced manufacturing process and extensive sales and service network, in the high-end market to occupy a larger share, mainly serving the equipment performance and precision requirements of large enterprises and scientific research institutions. Ltd. as a representative of the rapid development of domestic enterprises in recent years, through constantly increasing investment in R & D, improve product quality and technical level, gradually gain a firm foothold in the domestic market, and actively expand the international market. With in-depth understanding of the local market demand, high cost-effective and high-quality customized services, domestic enterprises have won the recognition of many customers in small and medium-sized enterprises and scientific research institutes and other market areas, and the market share is gradually expanding. At the same time, domestic enterprises continue to make breakthroughs in some key technologies, and the gap with international enterprises is gradually narrowing, and the competitiveness of the global vacuum heat treatment furnace market is increasing.

(ii) Development trend

Intellectualization and automation: In the future, vacuum heat treatment furnace will develop in the direction of intellectualization and automation. The introduction of artificial intelligence, machine learning and other technologies, so that the equipment can automatically analyze process data and workpiece characteristics, according to the preset process requirements to automatically optimize the vacuum, heating temperature, gas flow and other parameters, to achieve intelligent operation. At the same time, the integration of automated workpiece loading, transmission and detection system reduces manual intervention, improves production efficiency and product quality stability, and reduces labor intensity and human error in operation. In addition, remote monitoring, fault diagnosis and predictive maintenance of equipment are realized through IoT technology, which facilitates enterprises to carry out production management and equipment maintenance and realize intelligent manufacturing.

High precision and high performance: As the high-end manufacturing industry continues to improve the material performance requirements, the precision and performance of the vacuum heat treatment furnace has also put forward higher standards. The equipment will develop towards higher vacuum, more precise temperature control, more uniform cooling speed and more stable operational performance. For example, the development of vacuum heat treatment furnaces capable of realizing ultra-high vacuum environments (10-⁶ Pa and below), as well as heating systems with a temperature control accuracy of ±0.5 ℃, to meet the stringent demands of aerospace, semiconductor and other fields on material heat treatment, and to further enhance the comprehensive performance of materials and product quality. At the same time, it improves the reliability and stability of the equipment, reduces the probability of equipment failure, and lowers maintenance costs.

Energy saving and environmental protection and green manufacturing: driven by the growing awareness of environmental protection and the policy of energy saving and emission reduction, the vacuum heat treatment furnace will pay more attention to energy saving and environmental protection design. Adopt energy-saving heating elements, high-efficiency vacuum pumps and optimized gas circulation system to reduce the energy consumption of the equipment; develop waste heat recovery technology, recycle the heat generated in the heat treatment process and improve the efficiency of energy utilization. At the same time, reduce the emissions of waste gas, waste water and waste residue generated in the heat treatment process, and adopt environmentally friendly gas media and processes to realize green manufacturing, in line with the requirements of sustainable development. For example, the use of new environmentally friendly quenching medium to replace the traditional oil-based quenching medium to reduce environmental pollution.

Multi-functional integration and modular design: In order to meet the diversified needs of customers, the vacuum heat treatment furnace will be integrated with more functional modules, such as vacuum quenching, vacuum annealing, vacuum tempering, gas carburizing, nitriding, surface treatment and other functions, to achieve multi-purpose, to provide customers with more comprehensive heat treatment solutions. Through the modular design, the various functional modules of the equipment can be flexibly combined and replaced according to the customer's needs, which is convenient for the upgrading and maintenance of the equipment, improves the versatility and adaptability of the equipment, and reduces the customer's equipment purchasing and use costs. At the same time, strengthen the standardized design of equipment, improve the interchangeability and compatibility of equipment, and promote the healthy development of the vacuum heat treatment furnace industry.