Electric heating elements commonly used in high temperature vacuum furnaces

The common electrothermal elements used in high temperature vacuum furnace are refractory metal electrothermal elements and graphite electrothermal elements.

A. Refractory metal electrothermal elements

There are three shapes of refractory metal electrothermal elements:

(1) Coils or zigzag electrothermal elements made of wire. This kind of electrothermal element is not different from the electrothermal element used in non-vacuum furnace. It is mainly made of molybdenum wire. The coil is generally made of wire with a diameter of 22.5mm. The working temperature of the molybdenum wire electrothermal body does not exceed 1700 C. The zigzag electrothermal elements are made of wires with larger cross-section than coil electrothermal bodies. They require higher strength and require no less than 0.1-100Pa vacuum in the furnace when they are designed.

(2) Fibrous or rod-shaped electrothermal elements. This kind of electrothermal element is used at temperatures below 2300 C. The main material of the electrothermal body is tungsten, and sometimes molybdenum (working temperature is below 1700 C). The two ends of the rod are cast into the copper to form a protruding part, which enables the rod to be fixed. The upper end of each rod is cooled by water through the furnace cover, and the head part is sealed by a metal spring tube. The lower end of the rod is fixed on the water-cooled sector chassis. The electric heater made of tungsten rods is composed of nine rods arranged along the circumference.

The conductor of brazed electrothermal element is water-cooled copper pipe. Brazing is made of wire with diameter of 5 mm. The filamentous electric heater is composed of 12 tungsten brazes, which form a cylindrical heating space arranged along the circumference.

The main drawbacks of brazed and rod-shaped electrothermal elements are that a large number of water-cooled wires in the furnace cause great heat loss; they can not be divided into several heating zones to adjust furnace temperature according to height; generally, only one heating zone can be used in the furnace.

(3) Metal sheet electrothermal elements. Molybdenum or tantalum plates are used as electrothermal materials. Tungsten plate is generally not used because of the difficulties in machining and welding. The electric heater is cylindrical in shape, consisting of three thin plates with 0.2 mm edges. The lower part is fixed on a ring with 2 mm thickness. The upper part of each metal plate is welded (or riveted) with thin strips. The current is transferred from thin strips to the electric heater. These thin strips fix the electric heater on a copper water-cooled wire at the same time. This kind of electrothermal element has the best thermal conductivity because the whole surface participates in the heat exchange of the heated object. The disadvantages of this kind of electrothermal element are basically the same as those of brazed or rod electrothermal elements.

B. Graphite electrothermal elements

In addition to refractory metals, graphite is an electrically heated material comparable to refractory metals for electric heaters in vacuum furnaces. A good property of graphite compared with refractory metals is that its resistance varies little with temperature. Graphite has a high resistance and can use tens of volts of power supply when the section of the electrothermal body is large. Generally, graphite electrothermal elements are used in the vacuum of 0.1-100 Pa, and their service limit temperature is 2200 C. Under the above vacuum conditions, the working life of graphite is only tens of hours at 2300 C, but only a few hours at 2400-2500 C. It is worth pointing out that graphite has good thermal conductivity at low temperature, but at high temperature it decreases to a fraction of that at low temperature, so it will cause the temperature difference between the center and the outer surface of the electrothermal element, which will produce mechanical stress and lead to the damage of the electrothermal element. When designing graphite electrothermal elements, the stress produced by them should be calculated.

Three-Chamber-Gas-and-Oil-Double-Quenching-Vacuum-Furnace.

Customized-Vacuum-Gas-Quenching-Furnace-for-Hardening

Double-Chamber-Vacuum-Oil-Quenching-Gas-Cooling-Furnace

Vacuum-Oil-Quenching-Pressure-Gas-Quenching-Furnace

About the maintenance of vacuum tempering furnace?

With the prolongation of furnace operation time, the thermal resistance of heat shield decreases, and the electric heating element volatilizes and the resistance increases, so the power should be increased appropriately. In the practice of consumption, the experience calculation method is usually used to confirm the power, which is the relationship between the volume of graphite felt or refractory fiber felt heat shield vacuum furnace and heating power. According to the figure, 1300 can be confirmed. C vacuum furnace heating power. If it is a vacuum furnace with a metal heat shield, the heating power needed to be increased by about 30%.

Maintenance and maintenance of insulating screen of vacuum tempering furnace manufacturer plays an insulating and insulating role in vacuum furnace, and sometimes serves as the structural foundation of fixed heater. There are four types of heat shield: all-metal heat shield, sandwich heat shield, graphite felt heat shield and mixed felt heat shield. The main points of different heat shields should be controlled during maintenance.

Molybdenum and tungsten materials are usually used in the 1-2 layers near the electrothermal elements, while stainless steel materials can be used in the outer layers, and the thickness should be as thin as possible (medium-sized and small-sized furnaces are usually o.2). 0.5 mm. The large-scale furnace is o.5-1.Omm, and the heat shield should be processed into a bright state before assembling to reduce blackness and enhance reflection effect. 1300. The number of heat shield layers of C furnace is usually 5-6 layers, and the interval between layers is 5-10 mm. The contact area of several radiation plates should not be too large to reduce thermal short circuit. The heat shield should be expanded and contracted, and made into a detachable type, so as to facilitate the next maintenance.

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Vacuum-Sintering-Furnace-in-MIM-Industry

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Maintenance Method of Vacuum Sintering Furnace

Vacuum sintering furnace is widely used in vacuum sintering treatment of ceramics, silicon carbide, cemented carbide, photoelectric plating material and graphite purification. In order to maintain the vacuum sintering furnace, only good maintenance can be used for a longer time.

1. Cleaning operation of four distribution cabinets.

2. If the mesh belt is a top needle mesh belt, please grind the top needle end with sandpaper to prevent scratches on the battery sheet. If the mesh belt is inclined, it will be baked at low speed at 100 rpm to eradicate organic matter.

3. If the lamp tube is infected with organic matter, please be careful to scrub it with alcohol cotton or non-woven cloth.

4. Cleaning operation inside the cavity (need to pay attention to whether the stomata are blocked or not).

5. Cleaning operations of organic and hot exhaust (including plant operations and equipment, as well as equipment soot box), please use alcohol to clean the organic matter on the equipment, etc.

6. When disassembling and assembling the sealing structure on the furnace body, vacuum system and other parts, clean them with alcohol or gasoline and dry them, then coat them with vacuum grease and assemble them.

7. If there are inaccurate limit, control failure, clamping and other phenomena of transmission parts, they should stop immediately, and do not operate forcibly, so as to avoid damaging the parts.

8. After the shutdown of the vacuum sintering furnace, the vacuum in the furnace must be kept below 66.5 LPA.

9. Vacuum pumps, valves, measuring instruments, thermal instruments, electrical components and other accessories must be used, maintained and maintained in accordance with the technical specifications of the products.

10. Maintenance operation should be carried out without power supply. If it is maintained under live condition, it must be maintained by professional maintenance personnel, while ensuring the absolute safety of people and equipment.

11. Mechanical transmission parts of spot welding machine for aluminium plate in vacuum sintering furnace should be regularly refuelled or replaced for maintenance.


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Vacuum-Induction-Heat-Treatment-Graphitization-Furnace

Vacuum-Medium-Frequency-Induction-Melting-Furnace

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Vacuum Hot Press Furnace System Structure

Vacuum hot pressing furnaces are usually composed of several mechanical systems, as follows:

1. Vacuum system: It consists of oil diffusion pump, Roots pump, mechanical pump distribution electromagnetic pressure differential valve (to prevent sudden power outage, mechanical pump oil backfilling) inflatable valve, exhaust valve, vacuum butterfly valve, vacuum pressure gauge (+Pa) bellows, vacuum pipeline and support.

2. Hydraulic system: electric input mode is adopted. The hydraulic station is equipped with imported proportional valves, pressure sensors, displacement display, grating ruler (ranging accuracy 0.02 mm), hydraulic cylinder and other related hydraulic devices. The pressure regulation is semi-automatic and can be adjusted manually. The instrument can set the pressure automatically, and can realize voltage stabilization and holding.

3. Water cooling system: It is composed of various valve and pipeline related devices and has the function of automatically cutting off heating source or function of water-cut sound and light alarm.

4. Temperature control system: SCR is used to control temperature, equipped with PID function instrument and digital display meter. It has the function of over-temperature sound and light alarm. PLC touch screen can also be used to control temperature automatically, and historical data can be retained to facilitate the analysis of sintering process.

5. Inflation system: It is composed of various pipelines and valves, and equipped with electromagnetic vent valve and pressure sensor. When the pressure in the furnace is higher than the safety value, it will automatically vent. The inflatable pipeline is equipped with needle valve, which can control the inflatable volume.

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Technical Process of Read Vacuum Brazing Furnace Products

Vacuum brazing belongs to solid phase bonding, which is different from the melting method. The base metal does not melt during vacuum brazing. Because the brazing metal with lower melting temperature than the base metal is used, the heating temperature in the heating chamber of the vacuum brazing furnace is a connection method which is lower than the solid phase of the base metal and higher than the thick wire of the brazing fluid.

Vacuum brazing furnace is to coat the welded parts of the cleaned and decontaminated workpieces with flux, lay the solder on another part which needs to be welded, and also coat the welding surface with flux. After fixing the two parts, the vacuum brazing furnace will be heated to the temperature of solder melting to complete the welding.

It uses the furnace temperature to raise the temperature of the workpiece, and melts the solder whose melting temperature is lower than that of the workpiece, so that the workpiece can be welded.

In this process, heating should be as slow as possible to keep the internal and external temperatures of the products to be brazed consistent, otherwise the brazing quality will be directly affected.

Preheating, heat preservation, energy storage, heat preservation, brazing, heat preservation and power cut in industrial production are effective technological processes that can not only achieve the above objectives but also improve production efficiency. Vacuum brazing temperature and holding time are the key factors affecting brazing quality.

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Vacuum Brazing Furnace Knowledge

Vacuum brazing refers to the heating of workpiece in vacuum chamber, which is mainly used for welding products with high quality and oxidizable materials. Vacuum brazing furnace is a protective sintering furnace for heated articles in vacuum environment. There are many heating modes, such as resistance heating, induction heating, microwave heating and so on.

Vacuum induction furnace is a kind of furnace which uses induction heating to sinter the heated articles protectively. It can be divided into power frequency, intermediate frequency and high frequency. It can be classified as vacuum brazing furnace, including vacuum brazing with circular vacuum, which is mainly used in vacuum brazing of aluminium plate-fin heat exchanger, air conditioning evaporator, automobile heat exchanger, radar grid antenna and waveguide tube. It can be used for ageing and annealing of some nonferrous metals.

The size and position of the cylinder side wall and the pressure vessel of the door are designed to close one end of the cylinder side wall. The workpiece processing system is installed on the pressure vessel door to support the metal workpiece for heat treatment or brazing. The workpiece processing system includes a device that rotates the workpiece during processing. The vacuum system can be connected to the workpiece so that the internal pressure of the workpiece is lower than the atmospheric pressure during brazing. In view of the large-scale development of this kind of products, there are super-large and super-long furnace types to choose from, and equipped with a safe and reliable feeding and discharging truck system.

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Vacuum-Decarbonization-in-Vacuum-Furnace

Deep-decarbonization-of-vacuum-furnace

Induction Melting of High Nitrogen Stainless Steel

We have already known the application of induction melting in cast iron. In fact, induction melting technology plays an important role in other fields. High nitrogen stainless steel is a kind of steel with nitrogen content greater than 0.08% in ferrite matrix (mass fraction, the same below) or with nitrogen content greater than 0.4% in austenite matrix. So what effect does induction melting technology have on high nitrogen stainless steel?

First of all, we must understand that high nitrogen stainless steel, high nitrogen stainless steel has many advantages, such as high toughness and strength, good ductility, corrosion resistance, low permeability, high nitrogen stainless steel is superior to ordinary steel, mainly because of the addition of nitrogen element, if there is residual in the steel in the early stage, it will cause aging hardening, porosity and bias. After analysis, the steel castings with serious defects will be scrapped. Researchers later found that nitrogen can significantly improve the strength of steel and increase the corrosion resistance of steel.

In order to study the effect of nitrogen injection and addition of ferrochromium nitride on nitrogen enhancement of molten steel, the staff of scientific research center of our plant melted high nitrogen nickel-free stainless steel in vacuum furnace by induction melting technology, changing nitrogen partial pressure, temperature and adding ferrochromium nitride alloy. The theoretical results were estimated. By comparing the experimental results and theoretical results, it was found that changing nitrogen pressure and temperature could be smelted. The effect of increasing nitrogen partial pressure is more obvious when nitrogen-containing stainless steel is smelted. Adding nitrogen-containing alloy to melt high nitrogen stainless steel, the effect of increasing nitrogen is more obvious than adjusting temperature and nitrogen partial pressure, and the actual nitrogen content is higher than the theoretical value.

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Copper-Ore-Melting-Vacuum-Furnace-Price

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Development of Automatic Control System for Vacuum Furnace

Vacuum furnace is the main energy-consuming equipment in our production and life. According to the international advanced level, the utilization rate of energy in our country is very low, and the potential of energy saving is great. In order to make the temperature precision reach (+1 C), the control process of charging, pressurizing and solenoid valve required by mechanical action and heat treatment process of vacuum furnace can be automatically controlled with programmable logic controller (PLC), which greatly improves the reliability of the system and guarantees the heat treatment quality of the workpiece. SHlMADEN of Japan has recently developed a programmable vacuum furnace temperature controller FP-21, which inputs heat treatment temperature control curve and programmable parameters into the regulator. With its fast, intuitive and rich on-site working interface, the whole process of on-site furnace temperature control can be realized through the combination of different functions. Actual operation has good regulation effect, guarantees the accuracy of temperature control in each temperature section, realizes the automatic process control of vacuum furnace temperature, and greatly improves the heat treatment quality of precision mechanical parts.

In a word, the introduction of automatic control in vacuum furnace control system not only improves the welding quality and work efficiency of vacuum brazing, but also improves the economic efficiency of the system, and realizes the energy saving and sustainable development of the system.

The control principle is that the temperature signal is supplied to the regulator by the temperature detection element. The regulator sets parameters according to the programmable temperature control curve, carries out PID self-tuning in different time periods, and sends out control signals to the actuator thyristor power regulator. By adjusting the power of the electric furnace wire, the automatic control of the furnace temperature is realized. Because of the flexible curve programming function of the programmable regulator, the furnace temperature can be controlled in the whole process by choosing suitable parameters of the programming curve.

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Vacuum Industrial Furnace Advantages

1. The oxidation and decarbonization of the workpiece surface during heating can be eliminated completely, and the clean surface without deterioration can be obtained. This is of great importance to the improvement of the cutting performance of tools that only grind one side when grinding, such as twist drill grinding, which directly exposes the decarburized layer on the groove surface to the edge.

2. It does not pollute the environment and does not need to dispose of the three wastes.

3. The accuracy of furnace temperature measurement and monitoring has been greatly improved. The indication value of thermocouple and furnace temperature reach (+1.5) C. However, the temperature difference in different parts of a large number of workpieces in the furnace is large. If the forced circulation of rarefied gas is adopted, the temperature difference can still be controlled within the range of (+5) C.

4. High degree of mechatronics. On the basis of improving the accuracy of temperature measurement and control, workpiece movement, air pressure regulation and power regulation can be programmed in advance, and quenching and tempering can be carried out step by step.

5. Energy consumption is significantly lower than that of salt bath furnace. The heating chamber of modern advanced vacuum industrial furnace adopts insulation wall and barrier made of high quality thermal insulation material, which can highly concentrate the electric heat energy in the heating chamber, and the energy saving effect is remarkable.

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High-Quality-hot-galvanizing-annealing-Furnaces

Vacuum Atmosphere Furnace Characteristics

Atmospheric furnace is a high temperature furnace which integrates the double characteristics of box furnace and tubular furnace. It is suitable for the experiment and production with large sample proportion and atmosphere requirement. It adds the air inlet and outlet, the furnace body is sealed and welded. There is a ring of high temperature silicone rubber seal at the door of the furnace, and the sealing ring is equipped with water-cooling protection device. Therefore, vacuum ventilation atmosphere can be pumped during the test, and the vacuum effect can reach 100 Pa.

Resistance furnace of tubular atmosphere furnace mainly uses metallurgical, glass, positive and negative materials of lithium battery, new energy and other materials under certain atmosphere and vacuum conditions. There are single tube, double tube, horizontal, vertical, open, single temperature zone, double temperature zone, three temperature zone, multi-temperature zone and other furnace types. Suitable for heating and sintering of small sample workpiece, with safe and reliable, simple operation, good temperature control **, good heat preservation effect, wide temperature range, high furnace uniformity, multiple temperature zones, optional atmosphere, vacuum furnace type, can compile 31 sections of program, working mode will put the furnace tube into the furnace for heating.

The atmosphere furnace uses silicon-molybdenum rod as heating element and double shell structure. Phase shift trigger and thyristor control. Furnace uses alumina polycrystalline fibre material, double-layer shell is equipped with air cooling system, which can quickly cool down the temperature control system. Atmosphere furnace adopts shell integral seal, cover plate seal, silica gel pad and water cooling system. Gas passes through flowmeter and enters and exits from the back chamber. There are several inlets and outlets for washing furnace, which can pass hydrogen and argon. Gases such as gas, nitrogen, oxygen, carbon monoxide, ammonia decomposition gas, etc. The furnace has the advantages of balanced temperature field, low surface temperature, fast temperature rise and fall, energy saving and so on. It is an ideal product for atmosphere protection sintering and atmosphere reduction in universities, scientific research institutes, industrial and mining enterprises.

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Cooling System of Vacuum Furnace

What is the importance of the cooling system of the vacuum furnace?

Vacuum furnace refers to an industrial furnace heated by electrothermal elements in the near vacuum state. The cooling system of vacuum furnace is an important part of vacuum furnace. Cooling water should be kept clear, otherwise the water temperature will rise and cause shutdown. This is often neglected in the operation of vacuum furnaces. When unmanned, it may lead to significant destruction of vacuum furnaces.

The molybdenum heater in vacuum furnace will harden, shrink, fall, first fall over, then melt. In order to prevent hardening, collapse or sagging of vacuum furnace heating wire at high temperature, the structural dimensions of vacuum furnace heating wire, such as spiral resistance wire, bending diameter of heating element, pitch and spiral diameter, should be designed first. The heater is about to loosen by vacuum furnace insulation lining. 95 ceramics are put on the insulation lining, leaving proper expansion space. The shelf position should be suitable, usually 100 to 200 mm, and can be firmly hooked to prevent the resistance wire from lying on. In addition, direct contact (short circuit) between the furnace wires should be avoided, and isolators should generally be gasketed.

The purpose of treating cooling water by chemical assistant method of biodegradation is to keep minerals in suspension state and reduce the accumulation of sediments in rubber pipes, snake pipes and water jackets so as to make the water flow smoothly. This is usually accomplished by an automatic device, which can monitor the conductivity of water, automatically supplement chemicals, flush water and add fresh water. With the auxiliary steam filtration system, this method can also ensure the pH control of water and prevent the deposition of excess minerals in the cooling water system. After the system is stable, water quality tests should be conducted at least once a month to prevent overtreatment or inappropriate treatment.

The test samples of vacuum tempering furnace shell and heat exchanger material should also be placed in the water system, and the weight loss test should be done once a year to check the treatment effect. Special attention must be paid to the serpentine tube cooler of the diffusion pump. They should be checked regularly. If blocked, the diffuser pump will overheat and lose its function, and further cause the diffuser heater to burn down, resulting in expensive and time-consuming repair. When the serpentine cooling pipe is blocked, the water channel is disconnected from the water source, and the drainage is blown through with compressed air or washed with dilute acetic acid solution.

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Heat-Treatment-Technology-of-Dies-and-Moulds

Low-Tempering-Process

Vacuum-Tempering-Furnace-Classification

Vacuum Sintering Furnace Main Principles

Vacuum sintering furnace is a protective sintering furnace for heated articles in vacuum environment. There are many heating modes, such as resistance heating, induction heating, microwave heating and so on. Vacuum induction furnace is a kind of furnace which uses induction heating to protect the heated objects. It can be divided into power frequency, intermediate frequency, high frequency and other types, and can be classified as a subcategory of vacuum sintering furnace.

Vacuum induction sintering furnace is a complete set of equipment for sintering cemented carbide cutters and various metal powder compacts by using the principle of medium frequency induction heating under vacuum or protective atmosphere. It is designed for the industrial production of cemented carbide, dysprosium metal and ceramic materials.

I. Principles and Applications

Vacuum induction tungsten sintering furnace is under the protection of hydrogen gas after vacuum pumping. By using the principle of medium frequency induction heating, the tungsten crucible in the coil produces high temperature, which is transmitted to work by thermal radiation. It is suitable for powder forming and sintering of refractory alloys such as tungsten, molybdenum and their alloys by scientific research and military units. II. Main Structure and Composition

The structure forms are mostly vertical and discharging. Its main components are: electric furnace body, vacuum system, water cooling system, pneumatic system, hydraulic system, feeding and discharging mechanism, base, worktable, induction heating device (tungsten heater and advanced thermal insulation material), power supply device, medium frequency power supply and electrical control system, etc.

III. Main Functions

After vacuuming, hydrogen gas is filled to control the sintering state of pressure and atmosphere in the furnace. Optical fibre infrared radiation thermometer and armored thermocouple can be used to continuously measure temperature (0-2500 C). After comparing with the setting program, the intelligent temperature controller can choose to implement state feedback to medium frequency power supply, automatically control the temperature and heat preservation program.

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1200C-High-Temperature-Vacuum-Tube-Furnace

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Latest Wholesale Price of Vacuum Furnace

The vacuum furnace produced by our company integrates control system and furnace, and has compact and beautiful structure. The furnace lining is made of high purity alumina ceramic fiberboard, which has small heat storage, good heat preservation and energy saving effect, light weight and small space occupation.

The shell adopts double-layer air-cooling structure to ensure that the surface temperature of the shell is close to room temperature. The temperature control system adopts 0.2-level intelligent instrument with industrial precision, PID control and 51-stage programmable automatic control. The vacuum furnace is widely used in Colleges and universities, scientific research institutes and enterprise laboratories. It is an ideal equipment for sintering, melting, analysis and development of metal, non-metal and other compound materials.

Vacuum furnace uses alumina fiber as lining, silicon carbon rod or silicon molybdenum rod as heating element. Distribution of diffusion pump or molecular pump vacuum unit. It is widely used in heat treatment and copper welding of metal materials in high vacuum, reducing and protective atmosphere. Externally closed vacuum tank with water cooling system, the whole machine has novel structure, easy operation and affordable price.

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Heat-treatment-process

Vacuum-Annealing-Furnace-in-High-Nitrogen-Steel-Smelting

How to Control the Temperature of Vacuum Furnace

The temperature control system of vacuum furnace adopts an intelligent temperature control instrument with temperature control accuracy of 0.1%. According to the product process curve, a computer control program is compiled to control the temperature rise, heat preservation, cooling process and the operation of the temperature control instrument of the vacuum furnace. The automatic control of the vacuum furnace by the PC is stopped and the technical requirements of the temperature control of the process curve are realized.

Temperature control system can be set and stored, and each curve can be divided into multiple sections. Each temperature control curve has optional PID parameters and self-tuning function to ensure that there is no overshoot in the heating process. The system is suitable for multiple indexing thermocouples and pre-set heating and insulation curves.

The temperature controller outputs 4-20 mA current signal to the trigger unit, which converts the current signal into voltage signal. The output of the trigger unit controls the DC voltage and current of the excitation circuit, thus controlling the voltage and current of the electromagnetic regulation, and ensuring the vacuum furnace to be heated and kept warm according to the set curve. To complete temperature control, temperature sensing and control technology under vacuum is one of the key technologies of vacuum heat treatment process and equipment. The process of using vacuum furnace must be well mastered.

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Vacuum-Furnace-for-Metal-Smelting

Ultra-high-Temperature-Heating-Elements-in-Vacuum-Furnace

Precautions in the use of vacuum sintering furnace

Vacuum sintering furnace is a kind of hydrogen-filled protective state after vacuum pumping, using the principle of medium frequency induction heating, let the vacuum sintering furnace in the tungsten crucible in the coil produce high temperature, and then through the transmission of heat pairs to work, today I will tell you what things it should know when it is used.

1. Check that all parts and accessories in the control cabinet are complete and intact.

2. The control cabinet is installed on the corresponding foundation and fixed.

3. Anzhao wiring diagram, and referring to the electrical schematic diagram, connect the external main circuit and control circuit, and reliable grounding to ensure that the wiring is correct.

4. Check movable parts of electrical appliances should move freely without stuck.

5. Insulation resistance should be no less than 2 MOhms.

6. Valves of vacuum sintering furnace must be closed.

7. Control the power switch on the switch.

8. Manual pressure regulating knob rotates head counterclockwise.

9. Connect the circulating cooling water of the equipment according to the plan. It is suggested that the user connect a standby water (available tap water) at the total inlet and outlet pipe of the vacuum sintering furnace to prevent the seal ring from burning out due to the failure of circulating water or power failure.

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Vacuum heat treatment process equipment

Vacuum heat treatment equipment design and manufacturing involves a wide range of disciplines and technical fields, and related technologies are developing rapidly. Its main disciplines and technical fields include heat transfer, fluid (gas, liquid) mechanics, Electrotechnics and microelectronics, computer and control technology, mechanical design and manufacture, vacuum technology and vacuum unit, high temperature materials and special materials, sensors and sensing technology.

The application of these subjects and technologies in the design and manufacture of vacuum heat treatment equipment is too complicated and often leaks 10,000. The rapid development of new technologies and their infiltration into the design and manufacture technology of vacuum heat treatment equipment increase the difficulty of comprehensive theoretical discussion.

More than ten key technologies commonly encountered in the design and manufacture of vacuum heat treatment equipment are introduced in this paper, based on the recent technological progress and practical experience in developing vacuum heat treatment equipment. As a typical component (system) and basic key technology of vacuum heat treatment equipment design and manufacture technology, this paper elaborates. It is hoped that it can serve as inspiration and reference for scientific and technological personnel engaged in this work.

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Vacuum-Heat-Treatment-Technology-for-Cutting-Tools

Vacuum Furnace Five Advantages

Vacuum furnace protects the workpiece from oxidizing decarbonization, protects the oxidizable heating elements, reduces the gas content inside the workpiece, and adds more oxidizable elements to the melted metal. Vacuum furnaces have five advantages:

1. The oxidation and decarbonization of the workpiece surface during heating are completely eliminated, and the clean surface without deterioration layer can be obtained. This is of great importance to the improvement of the cutting performance of tools that only grind one side when grinding, such as twist drill grinding, which directly exposes the decarburized layer on the groove surface to the edge.

2. It does not pollute the environment and does not need to dispose of the three wastes. Double-chamber vacuum oil quenching furnace

3. The accuracy of furnace temperature measurement and monitoring has been greatly improved. The temperature difference between the thermocouple and the furnace temperature has reached (+) 1.5 (?) C. However, the temperature difference between different parts of a large number of workpieces in the furnace is large. If the forced circulation of rarefied gas is adopted, the temperature difference can still be controlled within (?) 5 (?) C.

4. High degree of mechatronics. On the basis of improving the accuracy of temperature measurement and control, workpiece movement, air pressure regulation and power regulation can be programmed in advance, and quenching and tempering can be carried out step by step.

5. Energy consumption is significantly lower than that of salt bath furnace. Modern advanced vacuum furnace heating chamber uses high-quality insulation material to make insulation wall and barrier, which can highly concentrate the electric heating energy in the heating chamber, and the energy saving effect is remarkable.


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Medium-Frequency-Iron-Induction-Melting-Furnace

Medium-Frequency-Iron-Induction-Melting-Furnace

500kg-Induction-Melting-Furnace

Medium-Frequency-Small-Vacuum-Induction-Melter-Furnace

Heat Treatment Skills of Vacuum Furnace

With the progress and development of industrialization, vacuum furnace plays an irreplaceable role in mould production. It is mainly used in ceramic firing, vacuum smelting, degassing of electric vacuum parts, annealing, brazing of metal parts, and ceramic-metal sealing. Vacuum heat treatment of vacuum furnace can realize almost all heat treatment processes, such as quenching, annealing, tempering, carburizing, nitriding, gas quenching, oil quenching, nitrate quenching, water quenching, vacuum brazing, sintering, surface treatment and so on. Vacuum furnace has high thermal efficiency, can achieve rapid heating and cooling, can achieve no oxidation, no decarbonization, no carburization, can remove the phosphorus chip on the surface of the workpiece, and degreasing and degassing, so as to achieve the effect of surface bright purification.

Generally speaking, the processed workpiece is heated slowly in the furnace, the difference of internal heat temperature is small, and the thermal stress is small, so the deformation is small. The qualified rate of products is high. The utility model can reduce the cost and has the function of degassing, thereby improving the mechanical performance and service life of the work. Good working environment, safe operation, no pollution and pollution. The treated workpiece has no danger of hydrogen embrittlement. It can prevent surface hydrogen embrittlement of titanium and refractory metal shell. The vacuum heat treatment process has good stability and repeatability. With these advantages, the development of vacuum heat treatment equipment and technology has been paid more and more attention and applied more and more widely.

Vacuum heat treatment is a comprehensive technology combining vacuum technology with heat treatment. It refers to all and part of heat treatment process carried out in vacuum. China divides vacuum into low, medium, high and ultra-high vacuum.

Vacuum furnaces and medium frequency electric furnaces have good prospects in the field of thermal processing. They are used for induction heating of diathermy, rolling, forging, pipe bending, heat treatment (quenching), welding and other processes. So what are the heat treatment techniques of vacuum furnace and medium frequency furnace?

1. Nitrogen should not be used as cooling gas when titanium alloy is treated in vacuum furnace, because titanium and nitrogen react at high temperature to form golden titanium nitride.

2. All the movable connections of the vacuum furnace are sealed with O-type rubber rings, which are cooled by water.

3. Vacuum quenching oil should be used to quench the workpiece in vacuum, which has lower saturated vapor pressure.

4. Vacuum furnace maintenance should be in the state of vacuum or pure nitrogen, to avoid suction and moisture absorption when not in use at ordinary times.

5. The pressure rise rate of domestic vacuum furnaces should not be less than 1.33Pa/h, and the standard of some foreign enterprises should be 0.67Pa/h.

6. Vacuum heating is mainly radiation, and the workpiece should be kept spacing in the furnace.

7. During the heating process, the workpiece and the material in the furnace will deflate and the vacuum will decrease.

8. The heating temperatures of vacuum tempering, vacuum annealing, vacuum solid solution treatment and vacuum aging are generally the same as those of conventional treatment.

9. Vacuum tempering furnace should have quick cooling device. The pressure of cooling water should be greater than 0.2 Mpa and the flow rate should be adjustable.

10. Cooling gas: steel generally uses 99.995% pure nitrogen, superalloy 99.999% nitrogen or argon, titanium alloy 99.995% argon.

11. Warming up: After putting into the workpiece, it can be heated only when pre-pumped to 6.67 Pa.

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