Vacuum heat treatment technology

As the requirement for surface quality and deformation of dies is getting higher and higher, ordinary heat treatment can not meet the requirement. Vacuum heat treatment equipment has the characteristics of no oxidation, degassing, keeping the surface of parts bright, energy saving and high efficiency. Now it has been widely used in aviation industry and die industry.

Vacuum heat treatment, as its name implies, is heat treatment in vacuum state. Vacuum state is the so-called negative pressure. The lower the pressure, the greater the vacuum degree, the less the gas in vacuum equipment, and the smaller the oxygen content of parts, which can prevent oxidation. There are many kinds of vacuum heat treatment furnace, such as vacuum annealing furnace, vacuum quenching furnace, vacuum tempering furnace, vacuum carburizing furnace, vacuum brazing furnace and vacuum sintering furnace.

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, the thermal stress is small, so the deformation is small; it can reduce costs, have degassing effect, thereby improving the mechanical performance and service life of the work; the working environment is good, the operation is safe, and there is no pollution and pollution.

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, etc. in the quenching process, so it is more and more widely used in the heat treatment industry.

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Vacuum Furnace in Experiment

Vacuum furnace is generally composed of furnace, electrothermal device, vacuum system, sealed shell, power supply system and temperature control system. Sealing furnace shell is welded with carbon steel or stainless steel, and the joint surface of removable parts is sealed with vacuum sealing material. In order to prevent the shell from deforming and sealing material from deteriorating after heating, the shell is usually cooled by water or gas.

The matters needing attention in the experiment of vacuum furnace, such as the structure of vacuum furnace, temperature control, heating technology and atmosphere in the furnace, will directly affect the quality of the product after the production of vacuum furnace. In forging furnace, increasing the temperature of metal can reduce the melting resistance, but too high temperature can cause grain oxidation or over-burning, which greatly affects the quality of products in vacuum furnace. In the process of heat treatment, if the steel is heated to a point above the critical temperature and then suddenly cooled, the hardness and strength of the steel can be improved; if the steel is heated to a point below the critical temperature and then cooled slowly, the steel will be more tough.

Vacuum oven, as its name implies, is high vacuum, because its structure is circular, it can extract high vacuum. Why do we need an atmosphere furnace when we have a vacuum furnace? This is in terms of price. Assuming that the vacuum of customer's demand is not high, the atmosphere furnace can meet his requirements, you say how he chooses. In addition, the atmosphere furnace generally intake and exhaust at the same time, through the maintenance of gas, can also prevent the atmosphere into the furnace, can fully meet the requirements of product processing.

Vacuum sintering in vacuum furnace means that powder, powder compact or other materials are heated at appropriate temperature in vacuum environment, and the bonding between particles is realized by means of atomic migration. The purpose of sintering is to make the porous powder compacts possess certain structure and properties of alloys. Selection of heat shield: The heat shield is the main part of the heating chamber of vacuum sintering furnace. Its main function is heat insulation, heat preservation and reducing heat loss. It is also the structural basis of fixed heater. Therefore, the structure and material selection of the heat shield have a great influence on the power and performance of the vacuum furnace (such as vacuum degree, exhaust rate, etc.)

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Vacuum Sintering Furnace of Classification

Vacuum sintering 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 circulating pressurized gas-cooled vacuum sintering furnaces.

Dual vacuum sintering furnace has two identical sintering furnaces, which share a set of vacuum pumping system and electrical control system. In operation, the two furnaces are used for heating and cooling respectively, and they are used 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.

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Low Temper Vacuum Tempering Furnace Technology

1) The cryogenic treatment box with continuous computer monitoring and automatic regulation of liquid nitrogen input and automatic temperature rise and fall is used.

2) The treatment process consists of three procedures: precisely compiled cooling and super-low temperature holding and rising along with temperature.

The reasons why cryogenic treatment can improve performance are analyzed as follows:vacuum-arc-furnace-for-Sintering

1) It transforms austenite with lower hardness into martensite with higher hardness, stability, wear resistance and heat resistance.

2) Carbide particles with higher hardness and finer grain size are widely distributed in the lattice of the treated materials by ultra-low temperature treatment.

3) A more uniform, smaller and denser microstructures can be produced in the metal grains.metal-box-type-electric-vacuum-muffle-furnace

4) Because of the addition of micro-carbide particles and finer lattices, the denser molecular structure is resulted, which greatly reduces the tiny voids in the material.

5) After ultra-low temperature treatment, the internal thermal stress and mechanical stress of the material are greatly reduced, which effectively reduces the possibility of tool and tool cracking and edge collapse. In addition, because the residual stress in the tool affects the ability of the cutting edge to absorb kinetic energy, the tool after ultra-low temperature treatment not only has high wear resistance, but also its own residual stress harm is greatly reduced than that of the untreated tool.

6) In the treated cemented carbides, new combinations of molecular structures are produced due to the reduction of electronic kinetic energy.25Kg-Vacuum-Induction-Furnace

Die Heat Treatment

Die heat treatment is to develop the potential of die materials and improve the performance of the die. The performance of the die must meet the requirements of high strength (including high temperature strength, cold and thermal fatigue resistance), high hardness (wear resistance) and high toughness, as well as good machinability, weldability and corrosion resistance.

Die heat treatment is divided into three parts: preparation heat treatment, final heat treatment and surface strengthening.

The new technology of thermo-mechanical heat treatment for residual heat of die forging is a new technology developed in recent years. The final forging temperature of most dies is about 850 C. After the final forging, it is not slow cooling, but rapid quenching, then high temperature tempering or spheroidizing annealing. This measure is not only to save energy, but also to improve the service life of the die.vacuum-brazing

The problems of non-uniform structure and dimension sensitivity exist in hot die. This is related to the cooling rate and cross section size of the die. Conventional high temperature heating, slow cooling and isothermal annealing processes are difficult to eliminate, but there are also some problems such as long annealing cycle, large oxidation burning loss and low die life. The rapid spheroidizing annealing process solves this problem effectively. Fast uniform annealing process is a short-term heating and cooling process at a heating temperature far higher than that of traditional annealing process to obtain less residual carbide, fine, high dislocation density and unstable structure, and then to be heated and cooled with furnace for the second time, i.e. short-term heating and homogenizing at the temperature of breaking through isothermal spheroidization and tempering, and then at the temperature of tempering and tempering. It is cooled to room temperature at a cooling rate greater than that of conventional annealing, thus rapid spheroidization is carried out.vacuum-heat-treatment-and-ordinary-heat-treatment

Die heat treatment is an important process to ensure the performance of the die. It has a direct impact on the manufacturing accuracy of the die, the strength of the plastic die, the working life of the die and the cost of the die.

For complex dies, whether the processing technology is correct or not often has a greater impact on the deformation of the dies. The comparison of heating processes for some dies shows that the heating speed is faster and larger deformation often occurs.vacuum-induction-melting-furnace

Vacuum Quenching Furnace Structural Characteristics

Among vacuum furnaces, vacuum quenching furnaces are the most widely used and representative typical equipment. They have complete and scientific quality management system, standardized production workshop, annual production capacity of 1000 electric furnaces, and the production scale is in the forefront of the industry. They are influential manufacturers of experimental electric furnaces and industrial furnaces in China.

Vacuum quenching furnace has the following characteristics:

1. Strict vacuum sealing is known to all that the heating and quenching of the workpiece are carried out in a closed vacuum furnace during vacuum heat treatment. Therefore, it is very important to ensure the vacuum degree of the vacuum quenching furnace to ensure the quality of the vacuum heat treatment of the workpiece. In order to ensure the vacuum performance of the vacuum furnace, the Kejia vacuum furnace body is welded by gas tightly with few holes on it, so as to minimize the chance of vacuum leakage. The components and accessories installed on the vacuum furnace body, such as water-cooled electrodes and thermocouple export devices, are also sealed structures.

2. Most heating and insulation materials can only use vacuum quenching furnace heating and insulation lining materials in vacuum and high temperature. These materials have the characteristics of high temperature resistance, low vapor pressure, good radiation effect and low thermal conductivity. For example, most vacuum quenching furnaces in China mainly use graphite as heating and insulation material. It is easy to oxidize when heated in atmosphere. Therefore, these heating and insulation materials can not be used in conventional heat treatment furnaces. The vacuum absorption of imported alumina fibers in Kejia vacuum furnace has better thermal insulation effect.vacuum-atmosphere-muffle-furnace-for-laboratory-gas-heat-treatment

3. The shell, cover, electrothermal element (water-cooled electrode) and heat insulation of vacuum furnace of water-cooled device all work in vacuum and heating state. In this extremely disadvantageous condition, it is necessary to ensure that the structure of each component is not deformed and damaged, and that the vacuum sealing ring is not too hot or burnt. Therefore, the components are equipped with water-cooling devices according to different conditions to ensure the normal operation of the vacuum furnace and sufficient service life.

4. When the vacuum degree reaches several hundred Pa, the glow discharge of the electrified conductor will occur at a higher voltage in the vacuum heat treatment furnace with low voltage and high current. Serious arc discharge will occur and the electric heating elements and insulation layer will be burned down, resulting in major accidents and losses. Therefore, the working voltage of the electric heating element of the vacuum heat treatment furnace generally does not exceed 80-100 volts. At the same time, the electrothermal elements should avoid the parts with sharp ends and the spacing between electrodes should not be too narrow to prevent the occurrence of glow discharge or arc discharge. 5. The high degree of automation is due to the operation of heating and cooling of metal workpieces, which requires dozens or even dozens of actions to complete. These actions are carried out in the vacuum furnace, which is inaccessible to the operator. At the same time, some actions such as heat preservation after the end of the quenching process of metal workpieces need to be more than one action and to be completed in a relatively short time. In such a rapid condition to complete many actions, it is easy to cause operator tension and constitute misoperation. Therefore, a higher automation program is adopted to control the vacuum furnace.Lowest-price-designed-programmable-temperature-control-lab-vacuum-furnace

How to select the heating chamber of vacuum degreasing sintering furnace?

The choice of vacuum degreasing sintering furnace should be based on its use and the performance of its components. Today, the vacuum furnace manufacturer introduces the selection of heating chamber for vacuum degreasing sintering furnace.stainless-steel-sintering

Selection basis of heating chamber of vacuum degreasing sintering furnace:

1. Graphite reflecting screen: Hard felt and soft felt are usually used in vacuum furnace. They are suitable for quenching, tempering and annealing of common steel. High temperature brazing, powder metallurgy and sintering, etc. Vacuum furnace manufacturer.

2. Metal heat shield; stainless steel and molybdenum are usually used in vacuum furnaces. Molybdenum reflector screen is suitable for high temperature and high demand for furnace environment, such as: superalloy, titanium alloy, magnetic data, quenching, annealing, high temperature brazing, sintering, etc. Stainless steel rice shooting screen is suitable for tempering, low temperature annealing, aging, vacuum aluminium brazing, and some low temperature furnace type selection. Vacuum furnace manufacturer.annealing-processes

Maintenance and Maintenance of Vacuum Sintering Furnace

After long-term use of vacuum sintering furnace, some impurities will remain in the furnace. We need regular maintenance to avoid damage to equipment. Today our vacuum furnace manufacturer focuses on the introduction of vacuum sintering furnace maintenance knowledge!molybdenum-powder-molding-sintering

1. When the vacuum sintering furnace is shut down, the vacuum state in the furnace should be kept below 6.65*104pa.

2. To clean the dust in the oven, soak the silk cloth with ethanol or gasoline and dry it.

3. When disassembling and assembling parts such as vacuum system or sealing structure on equipment, they should be cleaned with ethanol or gasoline, then coated with vacuum grease after drying and reassembled.

4. Avoid frequent scrubbing and keep the shell clean. Vacuum furnace manufacturer.

5. Workpiece trucks, material frames and workpieces should be cleaned and then put into the furnace to prevent moisture and impurities from entering.

6. When there are clamps, inaccurate limits and control failures in transmission parts, they should be eliminated immediately to avoid forced operation so as not to damage the equipment.tempering-principle-of-mold-steel

7. Regular refueling or changing of transmission parts. Vacuum furnace manufacturer.

8. Vacuum pumps, valves, measuring instruments, thermal instruments and electrical components and other accessories should be used, maintained and maintained in strict accordance with the instructions.

9. When repairing vacuum sintering furnace, it should be carried out under the condition of power failure. If it needs to be repaired under the condition of live power, it should ensure the absolute safety of maintenance personnel and equipment.sintering-of-titanium-and-titanium-alloy-materials

Heat Treatment of Automotive Parts

There are five main heat treatment processes for automobile parts: annealing and normalizing, quenching, tempering, aging and tempering, surface quenching and chemical heat treatment. Today, Xiaobian mainly introduces several commonly used heat treatment processes for automotive parts.Industrial-vacuum-pressure-free-sintering-furnace-for-diamond-segments

1. Carburizing Heat Treatment of Automotive Parts

The main purpose of carburizing heat treatment is to obtain good fatigue resistance and wear resistance of parts and to ensure the reliability of Parts'performance. Generally, differential gear, transmission shaft gear, steering shaft gear, engine piston and gear parts of automobile drive axle need carburizing heat treatment.vacuum-furnace-range-up-to-3000c

2. Tempering and Heat Treatment of Automotive Parts

The quenching and tempering heat treatment of automobile parts can be divided into protective atmosphere quenching and tempering heat treatment and general quenching and tempering heat treatment. Protective atmosphere conditioning and heat treatment can ensure that parts do not produce surface oxidation, peeling and other defects in the process of heat treatment, and ensure the surface quality of parts. If the quenched and tempered parts need follow-up processing, general heat treatment is carried out.Industrial-vacuum-gas-quenching-furnace-with-high-pressure

Metal Heat Treatment Market Report Aims To Outline and Forecast

Metal Heat Treatment Market Report Aims To Outline and Forecast

Metal Heat Treatment Market Research Report covers the present scenario and the growth prospects of the Metal Heat Treatment Market for 2016-2020. To calculate the market size, the report considers the revenue generated from the sales of Metal Heat Treatment globally. Metal Heat Treatment Market, has been prepared based on an in-depth market analysis with inputs from industry experts.
Metal heat treatment is a method used to change the physical and chemical properties of metals. Most metal components require thermal processing to change their metallurgical and physical properties to attain the desired engineering requirements for their intended use. Metal heat treatment involves the use of a vacuum furnace in which metals are heated to a particular temperature to change their metallurgical properties.
Metal heating furnaces enable heating metals up to 1,100ºC-1,500ºC (centigrade) and subjecting them to different types of processes such as annealing, hardening and quenching, brazing, and carburizing. In metal heat treatment, the absence of air and other gasses in the furnace prevents heat transfer through convection, thereby eliminating the possibility of contamination. This process renders excellent surface finishing to heat-treated parts.

Industrial vacuum furnace pressure quenching heat treatment research

Industrial vacuum furnace pressure quenching heat treatment research

A company's latest work in pressure quenching system is to improve the processing capacity of disc type vacuum heat treatment furnace, the company to obtain the high hardness can meet the strict parts as stress strain, the research objective of the fire. The adoption of pressurized gas in the vacuum furnace cooling system, improves the performance of the process and parts to improve, so lead to pressure vessel furnace in the whole industry. Because of the limitation of the furnace under positive pressure operation is very strict, this requires that the operator must strictly abide by rules of operation when using the device. The service life of the furnace due to the performance of the high pressure change, so must be of high pressure gas quenching furnace is often established test and operation procedures.
The pressurized gas quenching process is implemented by adopting high speed circulation gas, in order to achieve a high cooling rate, high velocity gas absolute pressure in l.s xlo5Pa. The low pressure quenching eliminates several atmospheric pressure under the strain of fire restrictions, reduces the vacuum container manufacturing costs, and greatly reduce the consumption of gas quenching. The characteristics of engineering design as soon as possible, the feasibility of repair was the pressure to consider the main problem in the design of quenching system. This furnace design feature is to emphasize the most popular and convenient, which in order to maintain and easy to close to the stove hot when charging, furnace furnace chamber is interrupted.

Vacuum Tempering Furnace

Vacuum Tempering Furnace

Vacuum Tempering Furnace is applied for heat treatment processes(quenching and tempering and bright atmosphere) of metal materials such as high speed steel, tool steel, tool steel, titanium alloy and parts of various materials under vacuum condition with a fast-cooling system, which is high efficiency.
The control system was controlled by PLC, temperature was controlled by intelligent temp controller, accurate control, high automation. User can choose auto or manual undisturbed switching to operate it, this furnace has abnormal condition alarming function, easy to operate.
Environmental protection performance has been improved, maintenance cost saving, energy cost saving.