Atmospheric Furnace Characteristics

Atmosphere furnace is a high temperature furnace which integrates the double characteristics of box and tube furnace. It is suitable for the experiment and production with large proportion of samples and the requirement of atmosphere. 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. So vacuum ventilation atmosphere can be pumped during the test. 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 shell is equipped with air cooling system, which can quickly cool down the temperature control system. Furnace uses shell integral seal, cover plate seal, silica gel pad and water cooling system. Gas enters and exits from the back chamber after flowmeter, and there are several inlets for furnace washing. 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 and industrial and mining enterprises.

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VACUUM FURNACE

industrial vacuum pumps,vacuum furnaces

Design Requirements of Industrial Furnace

The design or modification of industrial furnaces should select the right type structure and new energy-saving materials to increase mechanization and energy utilization as far as possible according to production requirements.

1. The part of uniform heat transfer effect with circular furnace instead of box furnace can strengthen the premise of using reasonable fireplace and increasing the space volume of heat exchanger with workpiece surface without increasing. As a result of reducing the heat loss of the outer wall round furnace and the furnace wall, the heat loss is reduced accordingly.

2. Use high-speed burner or installation in furnace fan to improve convective heat transfer in furnace. Especially the small high-speed air flow destroys the heat and mass transfer of the heater which is stagnated on the surface, and the lower boundary of the interface reaction gas shortens the heating time, and accelerates the function of increasing the temperature of the workpiece.

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Maintenance of Vacuum Furnace

In the process of using vacuum furnace, we usually encounter the problem of carbon deposit. Today, let's analyze some reasons for carbon deposit in vacuum furnace.

1. No charcoal burning for a long time;

2. Failure of carbon controller;

3. Long-term use of high carbon potential, excessive flow of rich gas, easy to appear furnace carbon deposition.

4. Uncontrolled atmosphere

5. The easiest carbon deposit is inadequate methanol cracking.

6. Excess adsorption due to poor decomposition

If carbon deposits in radiation tubes, the consequences will be more serious. It is easy to cause the furnace temperature to rise up or slow. In this case, we can tell you that burning carbon in vacuum furnace can effectively remove carbon deposits on Anti-carburizing bricks and radiation tubes. The method is that when there is no product in the front and back chambers of the vacuum furnace, the temperature of the back chamber should be around 800 C. Then open the front door with a sickle, then extinguish the fire-fighting sickle; open the middle door for about one minute, and then open the middle door for another minute after five minutes (so repeated three times). The carbon deposit in the furnace burns almost.

Vacuum Heat Treatment Furnaces

Vacuum Brazing Furnace

Vacuum stripping furnace

The method of arc heating and smelting metal in vacuum strip-throwing furnace. The electrodes used in this smelting method are self-consuming electrodes and non-self-consuming electrodes.

Consumable electrodes are made of melted materials (i.e. furnace charge), which are gradually consumed in the process of vacuum strip throwing furnace melting, while non-consumable electrodes are made of high melting point materials such as tungsten, which are basically not consumed in the process of furnace charge melting. Vacuum arc furnace with consumable electrodes is called self-consuming electrode arc furnace, which is short for self-consuming electrode arc furnace. Vacuum arc furnace with non-consumable electrodes is called non-consumable electrode arc furnace, which is short for non-consumable electrode arc furnace.

At present, non-consumable electrode smelting has been less used, and consumable electrode smelting has been widely used in production practice, becoming one of the main means of secondary remelting. Crucibles for vacuum arc melting are usually made of copper and cooled by water outside, which is called water-cooled copper crystallizer.

In vacuum strip-throwing furnace, consumable electrodes (melted materials) can be connected with negative electrodes, and water-cooled copper crystals can be connected with positive electrodes. Arc discharge occurs between the two poles after electrification, which converts electric energy into heat energy and produces high temperature to melt materials. In the melting process, the liquid metal droplets fall into the metal melting pool after passing through the high temperature arc zone, and solidify into ingots in the water-cooled copper crystallizer. Through a series of physical and chemical reactions between liquid metal and gas as well as in the molten pool, the purpose of improving the purity of metal and its crystalline structure and properties is achieved.

Vacuum Sintering Furnace

Vacuum Debinding Furnace

Medium Frequency Induction Melting Furnace

The working frequency of IF induction smelting furnace is between 50 Hz and 10 kHz, which needs frequency modulation by frequency converter. Medium frequency induction smelting furnace has more advantages than power frequency induction smelting furnace because of its high electric and thermal efficiency, short smelting time, less power consumption, less land occupation, lower investment, flexible production and easy implementation of process automation. It is suitable for smelting all kinds of cast iron, especially alloy cast iron, nodular cast iron and vermicular cast iron. It has strong adaptability to burden, and the variety and size of burden can be changed in a wide range. Medium frequency induction smelting furnace has the advantages that other iron smelting furnaces do not have, so it has gained remarkable development in recent years, and has been widely used in cast iron production.

With the continuous improvement of power density of medium frequency induction smelting furnace, the requirement of safety, lining life and noise is becoming higher and higher, and the rationality of furnace body structure is becoming more and more important. Heavy steel shell furnace has many advantages such as strong durability, high efficiency and productivity, low noise, easy maintenance and repair.

Heavy-duty steel shell furnace is different from frame furnace. It has a high strength annular steel shell with several large checkpoints. When the furnace is running, the checkpoints are closed and each checkpoint can be opened. The internal structure of heavy-duty steel shell furnace is strong, which can avoid the deformation that may be caused by tapping and pouring, and prolong the service life of furnace lining. Moreover, the sound absorption and isolation material can be added to the enclosed solid steel shell and its interior, which greatly reduces the working noise. The strong steel shell can also effectively protect the induction coil from the danger of splashing metal, so that the furnace has the greatest safety in operation. In order to effectively insulate and heat preservation and prolong the life of lining, cooling rings are installed at the top and bottom of heavy-duty steel shell furnace, which plays the role of uniform lining temperature and reducing thermal expansion. The stainless steel cooling ring with low energy consumption and high strength greatly improves the furnace efficiency.

Lab Vacuum Furnaces

Vacuum Graphitizing Furnace And Carbonization Furnace

Safety Characteristics of Vacuum Furnace

Vacuum furnace heat treatment is a comprehensive technology combining vacuum technology and heat treatment. It refers to all and part of the heat treatment process carried out in vacuum. China divides vacuum into low, medium, high and ultra-high vacuum. At present, the working vacuum of most vacuum heat treatment furnaces ranges from 1.33 to 1.33 x 10 Pa.

Vacuum heat treatment can achieve 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 heat treatment 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 has the function of 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. This series of advantages, the development of vacuum heat treatment equipment and process has been more and more attention and application.

Vacuum Brazing Furnace

Vacuum Induction Melting Furnaces

Production and Operation Flow of Vacuum Furnace

Work in the production workshop needs to be done with great care. A little carelessness will have inestimable consequences for life and safety. Especially in industrial production, we all know that Luoyang Kiln Factory is a big factory. The teachers in the experimental electric furnace, high temperature electric furnace, tubular furnace and vacuum furnace are trained and possessed before they go on duty. Certain experience shows the rigor of the production process, so what can be done to minimize the danger point in the specific operation of the vacuum furnace?

Every master of vacuum furnace knows how to start the power supply of vacuum furnace and set the switch of control cabinet at the position of automatic control. The parameters of the vacuum furnace process regulations are input into the computer. The workpiece is then smoothly fed into the furnace with a loading trolley, and the door (cover) is closed and locked to ensure sealing.

The cooling medium, cooling mode and pressure of vacuum furnace should be selected according to the technological requirements. Press the cycle start button, and the equipment executes the program: vacuum heating cooling is automatically completed. Remember to always check whether the equipment system is working properly, and report any abnormalities to the foreman in time. Before discharging, the normal pressure in the furnace should be restored, and the door (cover) should be opened after the indicator lamp is normal. When discharging, careful operation should be taken. No workpiece or tooling should collide with the furnace mouth.

Vacuum Debinding & Sintering Furnace

Vacuum Heat Treatment Furnaces

Vacuum Steam Quenching Furnace Characteristics

Vacuum quenching furnace is composed of heating furnace cover and movable chassis. It is a very advanced vacuum heat treatment equipment at present. Its excellent performance and unique design provide a wide range of vacuum bright gas quenching, annealing and magnetic materials for high precision parts of alloy materials such as high speed steel, die steel, stainless steel, alloy steel and titanium alloy. Sintering and rapid cooling of materials.

Equipment characteristics of vacuum quenching furnace:

(1) Temperature uniformity

The temperature uniformity required by users is achieved by circulating fan, air guide cover plate, furnace structure and electrothermal power.

Distribution and layout of electrothermal components, control mode and process, furnace door structure and other related design to ensure.

(2) Advanced mechanical systems

The advanced nature of the system is guaranteed by design, component selection and quality, and processing and manufacturing quality. The mechanical system runs smoothly and reliably, and the equipment is in low noise and low vibration state.

(3) Perfect control system

The system is stable and reliable, easy to operate, avoiding artificial misoperation, complete functions and so on.

(4) Quick and adjustable quenching transfer time

The double-speed lifting mechanism and advanced mechanical system make quenching transfer fast and reliable, and the time can be adjusted according to user's technological requirements.

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Vacuum Quenching Furnace Maintenance

After shutdown of the vacuum quenching furnace, the vacuum in the furnace should be kept below 66.5 LPA.

When the furnace is dusty or unclean, use alcohol or gasoline soaked silk cloth to wipe clean and dry it.

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

The outside surface of vacuum quenching furnace is often wiped, and its operation is clean and clean.

Parts and parts trucks need to be cleaned and dried before they can enter the furnace to prevent moisture and dirt from entering the furnace.

When the transmission parts are found to be jammed, inaccurate limit and control failure, they should be queued immediately and not be forced to operate so as to avoid damaging the parts. Aluminum plate spot welding machine mechanical transmission parts should be regularly refuelled or replaced for maintenance.

Vacuum pumps, valves, measuring instruments, thermal instrumentation, electrical components and other accessories are maintained and maintained according to the technical specifications of the products.

Maintenance operation should be carried out in case of power failure. In the case of live maintenance, we must ensure the absolute safety of people and equipment.

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Vacuum Annealing Furnace Characteristics

Vacuum annealing furnace is composed of two fixed hearth and a fixed furnace body at one end of 14 meters and a movable heating cover. The fixed hearth bears the vacuum muffle tank. The workpiece is heated in the vacuum muffle tank. The furnace temperature uniformity is higher (< 10 C); the all-fiber energy-saving lining can save more than 30% energy compared with the composite brick lining.

The movable hood is equipped with one end and vacuum muffle tank sealed fixed furnace door, the fixed furnace body is equipped with one end and vacuum muffle tank sealed fixed furnace door, the other end is open type, and has a sealing device, so that when combined with the movable hood and the furnace mouth are sealed firmly and reliably and naturally sealed. The side knife type soft seal is used between the hearth and the hood. The side knife of the hearth is inserted into the fiber of the hood when the hood enters the furnace, which makes the sealing between the hearth and the outside of the furnace adiabatic and simple and reliable. Roller grooves are arranged on the load-bearing base of muffle tank, and load-bearing rollers are placed in the groove, so that the muffle tank can move forward and backward freely when it expands and contracts.

A strong cooling fan and pipeline are installed at the end of the hearth, which can speed up the cooling speed after the heating process of muffle tank and improve the utilization rate of the furnace. Intelligent temperature program control system with high precision adopts Fuji high precision PID intelligent temperature control instrument. The program of heating and insulation can be set by itself, and the working condition of each zone can be controlled automatically by program. The temperature record adopts medium and long drawing with paper recorder, which can record the working condition of each zone of the furnace synchronously. This type has intuition. The temperature measurement and control points are set at the bottom and top of the furnace to control the furnace temperature balance within the allowable range, reduce the deformation of muffle tank during heating and cooling, prolong the service life of muffle tank and facilitate operation. The equipment has high degree of automation, safe and reliable operation, long service life and convenient operation and maintenance.

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Vacuum Gas Quenching Furnace Application

Usage and Characteristics: Mainly used in high-pressure gas quenching of high-speed steel, tool steel, die steel, alloy structural steel and other materials. It can also be used for brazing stainless steel at high temperature, solid solution, sintering and aging of powder materials, etc. Traditional horizontal single chamber furnace has mature structure, simple overall maintenance and high performance-price ratio.

Configuration Options: Inflation Pressure Selection: 0.6/1.0/1.5 MPa Special Material Process with Low Temperature Convection Heating Device; Low Pressure Control Device to meet the special atmospheric process requirements (such as inhibiting the volatilization of alloy elements); High Temperature Metal (Nickel Chromium, Molybdenum)/Graphite Material Heating System Selection to facilitate different temperatures or material process requirements According to the material and process requirements, the high vacuum/medium vacuum configuration can be chosen freely.

Steel-Wire-Annealing-Furnace

Electric-Resistance-Heating-Vaccum-Bright-Annealing-Furnace

Aluminium vacuum brazing furnace

The structure of aluminium vacuum brazing furnace should be advanced and reasonable. The heating elements should be uniformly arranged along the circumference of the heating chamber at 360 degrees, and the temperature uniformity is high. High-power and high-speed vacuum unit should be adopted. The vacuum recovery time is short.

Zonal temperature control, small workpiece deformation, high production efficiency. The utility model has the advantages of low cost, stable and reliable mechanical action, simple operation and flexible input of programming process. Manual/semi-automatic/automatic control, automatic alarm/display of faults. It can meet the requirements of vacuum brazing and quenching of the typical parts provided by users.

The aluminium vacuum brazing furnace should have reliable automatic control, monitoring, tracking and self-diagnosis functions at the international advanced level. Furnace supporting products and functional components have advanced international level, and can meet long-term, stable and reliable production needs. The energy-saving effect of the equipment is good.

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What is a vacuum tempering furnace

The tempering furnace is used for tempering ordinary metal parts in air and for quenching, annealing and aging heat treatment of light alloy parts such as aluminium alloy die castings, pistons and aluminium plates. The shell is welded with steel plate and section steel. The trolley is welded with section steel and steel plate. The trolley reduces heat radiation and convection loss by soft contact with the lining and sand sealing mechanism, thus effectively ensuring the sealing of the furnace body.

Tempering furnace is a periodic operation type tempering furnace, which is used for tempering ordinary metal parts after quenching and for quenching, annealing and aging heat treatment of light alloy parts such as aluminium alloy die castings, pistons and aluminium plates.

This furnace is mainly suitable for bright annealing and tempering treatment of black and non-ferrous metal wire, strip and pipe materials, mechanical parts, electronic components and modulus tools. After treatment, the surface of the product is smooth, non-oxidizing and non-decarbonizing.

All-fibre trolley tempering furnace is mainly used for heat treatment of large and medium-sized metal or alloy parts at rated temperature. The shell of this series of electric furnace is welded with steel plate and section steel. The trolley is welded with section steel and steel plate. The trolley reduces heat radiation and convection loss by soft contact with lining and sand sealing mechanism, which effectively ensures the furnace body. Sealability.

Full Fiber Well Tempering Furnace Uses:

Wellbore tempering resistance furnace is a periodic heat treatment equipment with hot air circulation system. The maximum temperature is 650 C. It is mainly used for high temperature tempering and annealing of various metal materials. It is the most ideal equipment for processing small shaft parts. It can automatically control the heating temperature of the equipment when used in conjunction with the control system.

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Vacuum Induction Furnace Summary

Vacuum induction furnace: Vacuum induction furnace is an important equipment in vacuum smelting. The problem of vacuum sintering exists in the process flow of product smelting with or without cutting. The purpose of sintering is to sinter the expected blank into a preform for hot forging, and to ensure good malleability and ductility structure, so as to avoid defects in hot forging. Vacuum smelting furnace is mainly used for smelting precision alloys, electromagnetic materials, alloy steel and high temperature materials.

Vacuum induction furnace is divided into discontinuous type and semi-continuous type. Furnaces with capacity less than 150 kg are mostly directional type. Furnaces with capacity of 150-300 kg have both. More than 500 kg are semi-continuous. Large-scale vacuum induction furnaces of 5-7t are more in foreign countries. Vacuum induction furnaces used in smelting industry in China are mainly small and medium-sized, and are now developing towards large-scale ones.

Vacuum acquisition is still a key problem in the design and application of vacuum induction furnace. Because the temperature in the vacuum induction furnace is about 2000 C, it is difficult to reach 10-0 Torr or higher vacuum at this temperature. According to the introduction of relevant information at home and abroad, the improvement of smelting quality is obviously related to vacuum degree. For this reason, users hope that the vacuum induction furnace designed can achieve 10-8 Torr or higher vacuum degree. At present, it is relatively easy to achieve 10-5 Torr vacuum degree.

Vacuum system of vacuum induction furnace consists of mechanical pump-booster pump or mechanical pump-diffusion pump to achieve 10-5~10-5 Torr vacuum, sometimes with Roots pump. The further improvement of service life and performance of vacuum units is still a subject that needs to be further discussed and solved in practical work.

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Vacuum-Induction-Melting-Furnace-for-Special-Steel

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Vacuum Gas Quenching Furnace Introduction

Vacuum gas quenching furnace is a kind of electronic equipment, which requires clean working environment, but in fact, few manufacturers can do it. Smoke dust is more, these dust and soot into the machine, will corrode the circuit board, although the factory has done a paint dipping treatment, but for a long time, the pins of electronic components will also occur leakage resistance, affecting the normal operation of vacuum gas quenching furnace. It is also necessary to affect the service life of vacuum gas quenching furnace. It is suggested that in harsh environment, it is better to install an exhaust fan to discharge soot and dust outdoors, so as to avoid entering or entering the machine as few as possible. Dust the machine on time.

Graphite heater is used in vacuum gas quenching furnace. Hard graphite felt is a single horizontal type with heat shield.

Graphite heater is used in vacuum gas quenching furnace. Hard graphite felt is a single horizontal type with heat shield. The vacuum gas quenching furnace consists of the main body of the vacuum furnace, the vacuum system, the water cooling system, the air charging system, the starting system and the relay control system. The gas quenching vacuum furnace is a visual operation interface. It is easy to operate and simple. It can switch automatically and automatically manually, and can complete the full active control. Vacuum gas quenching furnace has perfect sound and light alarm system, mechanical and electrical interlocking design, to ensure the safe and reliable operation of equipment.

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Vacuum-Gas-Quenching-Furnace-for-Steel-Materials

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Vacuum quenching furnace system

Vacuum quenching furnace is composed of vacuum furnace main engine, vacuum system, electronic control system, refilling system, pneumatic system, water cooling system and outside charging car.

Vacuum gas-cooled oil quenching furnace, heating part using graphite heater, multi-layer carbon felt insulation layer, rated temperature is 1320 C. Our vacuum quenching furnace can be used for both oil quenching and pressurized gas quenching (pressure less than 2 bar).

Vacuum quenching furnace is mainly used for vacuum gas-cooled oil quenching, pressurized gas quenching or solid solution treatment of cold working die steel, hot working die steel, high-speed steel, stainless steel, bearing steel and various oil-cooled steel. The surface of the workpiece treated by the furnace is bright, no oxidation and decarbonization, and the deformation is small. It is suitable for the workpiece with small processing allowance and easy decarbonization in the later stage.

Because of the special functions of degassing, purification and reduction in vacuum heating by using our vacuum quenching furnace, the service life of the workpiece after treatment has been greatly improved, which has very obvious economic benefits. And our vacuum quenching furnace production process does not have any toxic and harmful substances emissions, belongs to clean environmental protection equipment.

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Single-chamber-horizontal-high-pressure-vacuum-gas-quenching-furnace

Single-chamber-horizontal-vacuum-tempering-furnace

Single-chamber-horizontal-vacuum-annealing-furnace

Powder Metallurgy Vacuum Sintering Furnace Heating System

Structure and function of vertical high temperature vacuum sintering furnace system. According to the system requirements and operation process, a distributed and modular DCS control solution is designed. The hardware configuration and software design of the control system are discussed in detail. Real-time monitoring of process operation conditions of production equipment and online real-time display of controlled quantities are realized. The control scheme has the characteristics of simple hardware and flexible configuration, and is suitable for small and medium-sized control systems.

With the continuous development of science and technology, China's industry, national defense, aerospace and other fields have made considerable progress, including the vacuum equipment manufacturing industry, whether equipment level, production process, control technology has also been greatly improved. In addition, the continuous improvement of science and technology has also promoted the continuous development of material field, and some special materials and new materials have been widely used in aviation, aerospace, military industry, energy, chemical industry and other fields. Vacuum heat treatment technology plays an increasingly important role in the production of these special materials and new materials.

In view of the time-varying, large lag and non-linearity of powder metallurgy vacuum sintering furnace, the PID control effect is not ideal, and the fuzzy control algorithm is selected. The simulation models of PID control and fuzzy control are established and compared. The results show that the response speed of the system is very fast, the time to reach steady state is only 3.2 seconds, there is no overshoot, the steady state error is 1.2 C, and the steady state accuracy is very high. The output of the system simulation is close to the given input waveform, and the system regulation time is only 3.2 seconds. In a short time, it quickly enters a stable state, and the oscillation is very small. Fuzzy control is superior to traditional PID control and can meet the temperature control requirements of powder metallurgy vacuum sintering furnace.

Powder metallurgy vacuum sintering furnace is a time-varying, large lag, non-linear heating system. Because of the complexity of its physical and chemical mechanism, there are many influencing factors, so it is difficult to obtain an accurate mathematical model. When the parameters change greatly and the control precision is demanded high, the general PID control effect is very unsatisfactory. Fuzzy control does not require the system to give an accurate mathematical model. According to the actual experience of human beings, control rules are formulated and control decision tables are made. The system is controlled according to decision tables. It is especially suitable for sintering furnace, which is a complex industrial production object. The main factors affecting the quality of products in sintering process are sintering temperature and sintering time. Especially, the requirement of temperature is very strict. The maximum temperature difference is not allowed to exceed the given value of ~3 ~5. Therefore, it must be strictly controlled.

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Vacuum Sintering Furnace Technical Index

Vacuum sintering furnace is suitable for high temperature vacuum/atmosphere sintering or vacuum heat treatment of materials. It is used in cemented carbide, magnetic alloy, ceramics and powder materials industry. Mainly using medium frequency induction heating or resistance heating mode, the furnace body under the door or front and back door, hydraulic or electric lifting and discharging, vacuum and heating/cooling process can be fully automatic control.

 vacuum sintering furnace characteristics:

(1) Fully automatic program control and stable operation.

(2) Man-machine interface (optional).

(3) Uniform heating, small workpiece deformation, the highest temperature: 1300 ~1600 ~2000 ~C (optional).

(4) Strong cooling capacity, cooling gas pressure 0.2 MPa, 0.6 MPa, 1.0 MPa (optional).

(5) Energy conservation and no environmental pollution.

(6) A variety of protection functions to make the operation safer.

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Double-chamber-Horizontal-Oil-Quenching-Gas-Cooled-Vacuum-Furnace

Single-chamber-Horizontal-Hot-Pressing-Sintering-Vacuum-Furnace

Vacuum Brazing Furnace Type Characteristics

1) Hot fireplace

Brazing furnace adopts the form of separate vacuum chamber and heater, commonly known as hot fireplace. It is characterized by pumping air out of the container with brazing parts at room temperature, then pushing the container into the furnace. When brazing parts are heated in the furnace, vacuum pumping and heating are carried out simultaneously. After brazing, the container can be cooled out of the furnace, which shortens the production cycle and prevents the grain growth of the base metal. Vacuum brazing in hot wall furnace mostly requires vacuum pump to work continuously in the whole thermal cycle. To remove the gas released from the working load. In terms of size and maximum heating temperature, the hot-wall vacuum furnace is limited by the ability to withstand high pressure at brazing temperature.

The service temperature of this type of brazing furnace can be as high as 1150 C, which is limited to 870 C or lower in most cases. Heating furnace can use ordinary industrial electric furnace. This kind of vacuum vessel has no heating original parts and heat insulation materials. It is not only simple in structure and easy to operate, but also releases less gas during heating, which is conducive to maintaining vacuum. In order to improve productivity, several brazing containers are equipped to braze and cool the furnace gallbladder alternately. Therefore, equipment investment is low and productivity is high. However, the container is easily deformed under the action of external atmospheric pressure under high temperature and vacuum conditions, so it is suitable for small-scale production. The double container structure is often used in large-scale hot fireplace. The shell of the furnace is also designed as a low vacuum vessel, but its application is limited by the complexity of the structure.

2) Cold fireplace

Vacuum chamber is built in heating chamber, that is, heating furnace and vacuum brazing chamber are integrated, commonly known as cold fireplace. With this type of brazing furnace, the brazing parts must be cooled with the furnace after brazing, which limits the productivity. Thermal insulation materials and electric heating elements are included. Vacuum chambers are usually water-cooled. In order to concentrate the radiation heat on the workpiece and prevent the heat from dissipating to the furnace wall. A suitable heat shield (usually made of multi-layer molybdenum, tungsten, silver, graphite or other high temperature materials) is placed between the heating element and the furnace wall. The temperature can be as high as 2200 C and the pressure can be lower than 1.35 *10-4Pa.

Another type of cold-wall vacuum furnace has a double-layer water-cooling structure. Built-in heat reflecting screen, it is composed of thin metal plate with smooth multi-layer surface. According to the different temperature of furnace, molybdenum or stainless steel sheet is selected. Its function is to prevent heat from radiating outward, reduce heating of furnace shell and improve heating efficiency. Heating elements are distributed inside the reflecting screen, and different heaters are selected according to the rated temperature of the furnace.

When the cold hearth furnace is working, the temperature of the shell is not high because of water cooling and shielding by reflecting screen. It can withstand the external atmospheric pressure well, so it is suitable for high temperature brazing of large weldments. Its heating efficiency is also high, but it needs to be vacuum reheated before use. After brazing, the welding pieces can only be cooled with the furnace, and the temperature of the furnace decreases slowly in the low temperature stage, so the productivity is low. However, if two or more chambers continuous cold hearth furnace is adopted, the vacuum degree of heating chamber is not destroyed, and the filling, brazing, cooling and discharging of welding parts can be operated continuously, and the productivity can be improved.

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Vacuum Induction Tungsten Sintering Hydrogen Furnace

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.

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.

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.

Aluminum-Induction-Meling-Furnace-Made-in-China

horizontal-type-vacuum-induction-melting-furnace

Continuous-bright-vacuum-annealing-furnace

Gas Quenching Vacuum Furnace

Gas quenching vacuum furnace is composed of heating furnace cover and movable chassis. It is a very advanced vacuum heat treatment equipment. Its super function and planning together provide a wide range of high precision parts of alloy materials such as high speed steel, die steel, stainless steel, alloy steel, titanium alloy, etc. with vacuum bright gas quenching, annealing, magnetic materials. Sintering and rapid cooling of materials.

Equipment characteristics of gas quenching vacuum furnace:

(1) Temperature uniformity

Completing the temperature uniformity required by users is based on circulating fan, air guide cover plate, furnace structure and electrothermal power.

(2) Advanced mechanical systems

The advanced nature of the system is guaranteed by planning, component selection and quality, and manufacturing quality. The mechanical system works smoothly and reliably, and the equipment operates in low noise and low oscillation.

(3) Perfect control system

Reflected in 100 - 650 C can complete accurate temperature control, stable and reliable system, simple operation, to prevent human error operation, complete function and so on.

(4) Quick and adjustable quenching transfer time (gas quenching vacuum furnace)

Bottom-to-bottom door, double-speed lifting arrangement and advanced mechanical system make quenching transfer agile and reliable, and the time can be adjusted according to user's technological requirements.

Induction-Furnace-Melting-Cast-Iron

Vacuum-furnace-material-hot-forming

Vacuum-Brazing-Furnace-Composition-and-Characteristics

Vacuum-Quenching-Furnace-Equipment-Structure

Powder metallurgy vacuum sintering furnace

Structure and function of vertical high temperature vacuum sintering furnace system. According to the system requirements and operation process, a distributed and modular DCS control solution is designed. The hardware configuration and software design of the control system are discussed in detail. Real-time monitoring of process operation conditions of production equipment and online real-time display of controlled quantities are realized. The control scheme has the characteristics of simple hardware and flexible configuration, and is suitable for small and medium-sized control systems.

With the continuous development of science and technology, China's industry, national defense, aerospace and other fields have made considerable progress, including the vacuum equipment manufacturing industry, whether equipment level, production process, control technology has also been greatly improved. In addition, the continuous improvement of science and technology has also promoted the continuous development of material field, and some special materials and new materials have been widely used in aviation, aerospace, military industry, energy, chemical industry and other fields. Vacuum heat treatment technology plays an increasingly important role in the production of these special materials and new materials.

In view of the time-varying, large lag and non-linearity of powder metallurgy vacuum sintering furnace, the PID control effect is not ideal, and the fuzzy control algorithm is selected. The simulation models of PID control and fuzzy control are established and compared. The results show that the response speed of the system is very fast, the time to reach steady state is only 3.2 seconds, there is no overshoot, the steady state error is 1.2 C, and the steady state accuracy is very high. The output of the system simulation is close to the given input waveform, and the system regulation time is only 3.2 seconds. In a short time, it quickly enters a stable state, and the oscillation is very small. Fuzzy control is superior to traditional PID control and can meet the temperature control requirements of powder metallurgy vacuum sintering furnace.

Powder metallurgy vacuum sintering furnace is a time-varying, large lag, non-linear heating system. Because of the complexity of its physical and chemical mechanism, there are many influencing factors, so it is difficult to obtain an accurate mathematical model. When the parameters change greatly and the control precision is demanded high, the general PID control effect is very unsatisfactory. Fuzzy control does not require the system to give an accurate mathematical model. According to the actual experience of human beings, control rules are formulated and control decision tables are made. The system is controlled according to decision tables. It is especially suitable for sintering furnace, which is a complex industrial production object. The main factors affecting the quality of products in sintering process are sintering temperature and sintering time. Especially, the requirement of temperature is very strict. The maximum temperature difference is not allowed to exceed the given value of ~3 ~5. Therefore, it must be strictly controlled.

High-Quality-Manganese-Alloy-Melting-Industrial-Electric-Arc-Furnace.

Quality-Vacuum-Induction-Heating-Laboratory-Sintering-Furnace

Vacuum-Atmosphere-Muffle-Furnace-for-Metal-Annealing

Silicon-Carbide-Vacuum-Induction-Heating-Sintering-Furnace

Diffusion Welding Equipment Composition and Structure

The main and secondary factors of vacuum diffusion welding and LF21 are heat preservation time, heating temperature and applied load in turn. The level is heat preservation time 60 min, heating temperature 540 C and applied load 4 MPa. At this time, the strength of welded joint is very high. The diffusion rate of copper is relatively faster than that of aluminium. The diffusion zone basically distributes on the interface of aluminium side. The hardness of the diffusion zone is much higher than that of the base metal. The intermetallic compound CuAl2 was formed at the interface between diffusion zone and copper matrix of the Cu/Al joint, and the eutectic of alpha(A1)+CuA12 was formed at the interface between diffusion zone and aluminum matrix. The metallurgical bonding of copper and aluminium was realized in the diffusion zone.

Polymer diffusion welding equipment is a kind of welding equipment, which joins copper and aluminium weldments tightly at a certain temperature and pressure for a period of time, and makes atoms between the contact surfaces diffuse to form a joint. The main factors affecting diffusion welding process and joint quality are temperature, pressure, diffusion time and surface smoothness.

Diffusion welding has the advantages of no solder, traceless welding, smooth workpiece appearance. The equipment can adjust the output current and pressure, so that the workpiece can get a reasonable heating speed. The workpiece clamping mechanism adopts oil pressure control system, which makes the clamping of the workpiece stable and stable.

The main function of the polymer diffusion welding machine is to realize the diffusion welding between materials and molecules. The equipment mainly produces electric power, chemical industry, smelting and other industries. It can produce bus expansion joints and soft-connected conductive belt products urgently needed by the industry. It can realize the diffusion welding between soft bus, soft bus and hard bus and hard bus. Diffusion welding.

Pressure-sintering-furnace-cemented-carbide

High-Temperature-Vacuum-Furnace-Manufacturer

High-Temperature-Vacuum-Diffusion-Welding-Molding-Machine

Low-temperature-tempering-process

Vacuum Furnace Classification

Vacuum furnace is mainly used for sintering metal powder products, metal injection forming products, cemented carbide, ceramics, Nd-Fe-B, stainless steel non-woven fabrics, etc.

The structure of the high temperature vacuum sintering furnace is basically the same as that of the vacuum heat treatment furnace, except that appropriate changes are made according to the sintering process. Vacuum sintering furnaces are divided into double vacuum sintering furnaces and single outdoor pressurized gas-cooled vacuum sintering furnaces, which have two identical sintering furnaces, a common set of vacuum pumping system and electrical control system. In operation, the two furnaces are used for heating and cooling respectively and alternately.

The furnace has the functions of degreasing, pre-sintering and sintering in the same furnace at one time. The degreasing system includes external pipelines, vacuum valves, condensers, collectors and mechanical pumps. In order to meet the requirements of Nd-Fe-B sintering process, a vacuum unit with high vacuum and large pumping speed should be equipped in a single outdoor circulating pressurized gas-cooled sintering furnace. The structure of the furnace is the same as that of a single-chamber outdoor circulating pressurized gas quenching vacuum furnace.

Silicon-Nitride-Hot-Press-Sintering-Furnace

Hot-Pressure-Tungsten-Carbide-Sintering-Furnace

Cemented-Carbide-Vacuum-Induction-Furnace

Powder-Metallurgy-Carbonization-Vacuum-Induction-Furnace

Introduction to the Performance of Vacuum Annealing Furnace

Vacuum annealing furnace is mainly used for bright annealing of superalloy steel, magnetic material, non-ferrous metal, stainless steel, titanium alloy, etc.

The structure characteristics of vacuum annealing furnace are as follows: the heating chamber adopts stainless steel skeleton; the heat shield is a multi-layer reflecting screen with long service life and easy maintenance; the failure rate is low; the air-cooling system is composed of high-speed motor, high-pressure impeller with large air volume, and guide plate, copper-copper heat exchanger and guide device, so that the air flow can be realized by heat exchanger-fan-guide device. - The high-speed cycle of workpiece-heat exchanger enables the workpiece to be cooled quickly and evenly. The electronic control system adopts the way of PLC and programmable temperature controller to realize three control modes: full-automatic, semi-automatic and manual, with flexible operation.

Cautions for the use of vacuum annealing furnace: 1. The parameters on the vacuum meter have been adjusted. No arbitrary modification and setting are allowed. 2. During operation, attention should be paid to the changes of current, voltage and water temperature at any time, and any abnormalities should be dealt with or reported in time. 3. It is strictly forbidden to deal with electrical faults privately, so electricians should be asked to remove them. 4. If the touch screen breaks down, the manual/automatic switch can be put into the manual file, and the vacuum pumps, valves and temperature controllers can be operated from the beginning. The operation steps of the vacuum pumps, valves and temperature controllers are the same as those of the automatic ones, but the manual operation mechanism can be changed from the touch screen to the button.

The advantages of vacuum annealing are as follows: 1. No oxidation, decarbonization and carbon addition have good protection on the inner and surface of the workpiece. After vacuum annealing, the workpiece has primary color 2. Improve the overall mechanical properties, degassing and promote the purification of the metal surface. 3. It can reduce the volatility of gold-bearing elements in workpieces. 4. Vacuum annealing furnace has high thermal efficiency, controllable heating and cooling rate, good stability and repeatability. 5. Workpiece deformation is small, reducing the subsequent processing procedures and saving costs.

High-quality-vacuum-induction-melting-furnace-for-sale

lab-vacuum-high-temperature-horizontal-tube-furnace

Electric-Vacuum-Nitriding-Furnace-for-Metal-Melting

Heat Treatment Processing Technology of Experimental Electric Furnace

Heat treatment methods generally include three whole processes: heating, heat preservation and cooling. Sometimes only two whole processes are needed. These processes are interlinked and cannot be interrupted.

When metal material is heated, the workpiece is exposed to gas, which often produces air oxidation and decarbonization (that is, the carbon content on the surface of iron and steel parts decreases), which is harmful to the surface characteristics of the parts after quenching and tempering. Therefore, metal materials should be heated in controllable or protective atmosphere, molten salt and vacuum, and protective heating can also be carried out by coating or packaging.

The heating of experimental electric furnace is one of the important processes of quenching and tempering treatment. There are many ways of heat treatment of metals. At first, charcoal and coal were used as pyrogens, and liquid and gas fuels were used. The use of electricity makes heating easy to control and free from air pollution. These pyrogens can be heated immediately and indirectly through molten salts or metal materials or even floating particles.

The cooling of the experimental electric furnace is also an indispensable process in the whole process of heat treatment. The cooling mode varies with the process. The key is to control the cooling rate. Generally, the cooling rate of annealing is the slowest, normalizing is faster and quenching is faster. However, there are different requirements because of different steel grades. For example, air-hardened steel can be hardened by normalizing at the same cooling rate.

Heating temperature is one of the important process parameters of heat treatment method. Selecting and manipulating heating temperature is the key to ensure the quality of quenching and tempering treatment. The heating temperature varies with the purpose of the treated metal materials and quenching and tempering, but it is generally heated above the phase transition temperature to obtain the high temperature structure. Another change takes a certain time, so when the surface of the metal workpiece exceeds the required heating temperature, the temperature must be maintained for a certain period of time, so that the internal and external temperatures are consistent, so that the microstructures change completely. This period is called holding time. When choosing high energy density heating and surface conditioning treatment, the heating rate is very fast, generally there is no heat preservation time, and the heat preservation time of chemical conditioning treatment is often longer.

High-Temperature-Tungsten-Carbide-Vacuum-Sintering-Furnace

Customized-Hydrogen-Sintering-Furnaces

Customized-hydrogen-brazing-furnace

Vaccuum-Nitriding-Furnace

High Temperature Box Atmosphere Furnace

High temperature box atmosphere furnace is an advanced experimental equipment, which is suitable for diffusion welding of metals, nano, single crystal silicon, polycrystalline silicon, batteries, etc. and heating equipment of atmosphere heat treatment under vacuum gas protection. Mainly used in material testing, synthesis, sintering and so on. The furnace body has good thermal insulation performance and remarkable energy saving effect. It can also be used for vacuum hot pressing sintering of composites, powders, structural ceramics and alloys.

The electric part of the high temperature box type atmosphere furnace adopts an integrated structure with the furnace body. The whole electrical component is installed on one side of the bottom of the furnace body, which has compact structure and occupies less space. Temperature control is installed on the side panel of the furnace body. The observation is intuitive and the adjustment is convenient. The temperature control instrument has the function of expert PID adjustment. It can automatically track and set the best PID value. It can arbitrarily set the measuring indexing password. At the same time, it has the function of compensation, which can make the furnace temperature consistent with the display value.

The gas passes through the flowmeter and enters and exits from the back chamber. There are burning nozzles at the inlet and outlet of the furnace, which can pass hydrogen, nitrogen, oxygen, carbon monoxide, ammonia decomposition gas and other gases. The furnace has the advantages of balanced temperature field, low surface temperature, fast temperature rise and fall, energy saving and so on. It is a university, scientific research institute, industrial and mining enterprise. It is an ideal product for atmosphere protection sintering and atmosphere reduction.

The high temperature box-type atmosphere furnace body is equipped with a vacuum pipeline. First, the air in the furnace is pumped out and then protected by hydrogen or ammonia decomposition gas. The intake port is equipped with a flowmeter to check the gas input. KPa micrometer is installed on the top of the high temperature box atmosphere furnace to show the pressure in the furnace. A gas collector is installed to check the purity of the gas. The furnace mouth is equipped with exhaust gas outlet and condensate water outlet. All pipelines are centralized, easy to operate, beautiful and generous.

Vacuum-Heat-Treatment-Furnace-Types

Vacuum-Sintering-Furnace-with-Nitrogen-Atmosphere

Vacuum-Degreasing-Sintering-Furnace-Heating-Chamber

Vacuum High Pressure Gas Quenching Furnace Structural Characteristics

Vacuum furnace can be divided into different types. Today, we introduce the use and structure characteristics of vacuum high pressure gas quenching furnace.

Usage: Vacuum high pressure gas quenching furnace is mainly used for quenching high speed steel, tool and die steel, stainless steel, solid solution treatment of stainless steel and titanium alloy, vacuum heat treatment of magnetic materials, high temperature brazing and vacuum sintering, and low temperature tempering with convection fan.

Structural features: The heating chamber adopts stainless steel skeleton and new carbon felt composite material, with less deformation, high temperature and pressure resistance, long service life, easy maintenance, graphite tube heater, easy installation and maintenance, and low failure rate.

Air-cooled by jet cooling, graphite nozzle circumferential distribution, so that the high-pressure air flow more reasonable, part of the main air duct air volume can be adjusted, customers can control part of the main air duct air volume according to the characteristics of the workpiece, can effectively control the deformation of the workpiece. High-speed, high-pressure and large-flow fan, copper-copper high-efficiency circular heat exchanger, to achieve high-speed cooling.

The fan can adopt single speed, double speed and variable frequency speed regulation to control the air cooling speed. The heating chamber can also adopt all-metal structure to meet the requirements of solid solution treatment of titanium alloy and precision alloy. The electronic control system adopts the way of PLC and programmable temperature controller, realizes three control modes: automatic, semi-automatic and manual, and has flexible operation.

Heat-Treatment-Furnace-Vacuum-Tempering-Furnace

1200ºC--Vacuum-Tempering-Furnace

Tempering-Furnace-with-Vacuum-Tube

Pit-Type-Vacuum-Tempering-Furnace-for-Axis

How to install vacuum furnace?

Vacuum furnaces may not be unfamiliar to everyone, but there are many problems about the installation of vacuum furnaces, so how to install the vacuum furnaces is correct? How to use the vacuum furnaces correctly?

1. Attention should be paid to the installation of graphite electrothermal elements and water-cooled electrodes in vacuum furnaces.

 Graphite elements should be handled with great care in case of damage.

The bolts should be tightened reliably in order to achieve good electrical contact. Do not exert too much force to avoid thread breaking.

2. The layout, installation location and civil conditions of the vacuum furnace provided in the reference paper. Select the permanent installation site of equipment and carry out civil construction. Installation site should be free of smoke and dust pollution, clean environment, dry air, should not be put together with other equipment, maintain room temperature of 10-35 C, smooth and clean ground.

3. Connect the pipeline to the refilling pipeline according to the system diagram of the refilling system of vacuum furnace. It is suggested that high purity nitrogen with purity of 99.99%-99.999% be provided as refilling gas.

4. According to the water cooling system diagram, the intake and drainage pipes are connected to the inlet and drainage ports of the furnace respectively, providing water sources with pressure of 0.1-0.15 MPa, temperature of no less than 15 C and no higher than 30 C. It is better to provide circulating water and rust-proof water.

5, the vacuum system is positioned according to the vacuum system diagram, assembled and connected with the furnace body. When assembling, the O-ring is coated with a thin layer of vacuum grease, and the flange is tightened evenly.

6. The furnace body and control box of the vacuum furnace are grounded, and the grounding resistance is less than 4 Euros. The gauge cable of the instrument and the vacuum gauge should also be grounded.

7. Connect the power supply to the corresponding electrical connection according to the electrical wiring diagram, check the voltage of the power supply, connect the control box, the power box and the wire and cable between the furnace body.

8. Provide a pneumatic source with a minimum pressure of 0.5 MPa. Industrial nitrogen can be used. If compressed air is used, self-contained pneumatic "three major components" (such as oil mist, pressure reducer and water separator) will be provided.

9. Install other vacuum furnace components, including conduits, measuring instruments, etc.

Heat-treatment-of-powder-metallurgical-materials

Vacuum-Dryer-for-Thermosensitive-Materials

Carbonitriding-heat-treatment-process.

Heat-Treatment-of-Automotive-Parts

Vacuum stripping furnace

Vacuum heat treatment process can improve the service life of parts. It is the most advanced heat treatment process in the contemporary era, and has been widely recognized.

The popularization of vacuum furnace came into being under the background of this era. Vacuum furnace is carried out in the vacuum state during the heat treatment of parts, which completely avoids the problem of oxidation. The performance of parts after vacuum heat treatment is more stable and reliable, which provides a guarantee for precision workpiece processing. According to statistics, the service life of parts processed by vacuum furnace is 30% higher than that of parts processed by ordinary process, even several times higher under the condition of similar hardness.

When we use vacuum furnaces, we will also face some problems that heat treatment process can not be completed in vacuum furnaces. There are roughly two reasons. One is that vacuum furnaces manufactured by vacuum furnaces manufacturers according to the standards of vacuum furnaces, although the technical parameters are qualified, heat treatment process is not considered comprehensively and systematically in the process of producing vacuum furnaces, which leads to the following problems. The parameters of vacuum furnace do not match those of heat treatment. Secondly, there are some defects in the vacuum heat treatment process, which can not achieve the desired results.

Sintering-Furnace-for-Vacuum-Sintering-MIM

3000-Degree-Graphitization-Vacuum-Induction-Furnace

Customized-Vacuum-Degreasing-Sintering-Furnace

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