Vacuum heat treatment furnace

---

Technology is introduced

Vacuum heat treatment is a comprehensive technology combining vacuum technology and heat treatment. It refers to the whole and part of heat treatment process is carried out in vacuum. Vacuum in China is divided into low, medium, high and ultra-high vacuum.Vacuum heat treatment can almost achieve all heat treatment processes, such as quenching, annealing, tempering, carburizing, nitriding, in the quenching process can achieve gas quenching, oil quenching, nitrate quenching, water quenching, etc., can also be vacuum brazing, sintering, surface treatment, etc. Vacuum heat treatment furnace has high thermal efficiency, can realize rapid temperature rise and cooling, can realize no oxidation, no decarburization, no carburization, can remove the phosphorus chips on the surface of the workpiece, and has degreased and degased functions, so as to achieve the effect of bright surface purification. Generally speaking, the workpiece is processed in the furnace heating slowly, the temperature difference between internal heat is small, the thermal stress is small, so the deformation is small. The qualified rate of products is high. Can reduce the cost, has the degassing effect, thus improves the working mechanical properties and service life. Good working environment, safe operation, no pollution and public hazards. The processed workpiece has no danger of hydrogen embrittlement, and the surface of titanium and refractory metal shell is prevented from hydrogen embrittlement. The vacuum heat treatment process has good stability and repeatability. This series of advantages, the development of vacuum heat treatment equipment and technology is more and more attention and application more and more widely.

General metal materials are heated in the air furnace. Due to the existence of oxygen, water vapor, carbon dioxide and other oxidizing gases in the air, the oxidation of these gases and metal is easy to produce oxide film or oxide skin on the heated metal surface, and completely lose the original metallic luster. The gas also reacts with the carbon in the metal to decarbonize its surface. If the furnace contains carbon monoxide or methane gas, it will also carburize the metal surface. For chemically active Ti, Zr and insoluble metals W, Mo, Nb and Ta, heating in an air furnace will not only generate oxides, hydrides and nitride, but also absorb these gases and diffuse into the metal interior, which will seriously deteriorate the performance of metal materials. These oxidation, decarbonization, carburization, inhalation and even corrosion and other ills, in the controlled atmosphere furnace or salt bath furnace heating, sometimes also difficult to avoid. In order to solve this problem, the usual practice is to leave machining allowance before the heat treatment of the workpiece, and remove the oxidation and decarburization layer after the heat treatment.

Main USES: applicable to electronic ceramics with high temperature structure ceramic sintering, glass precision annealing, mould processing and micro precision annealing crystallization, crystal, ceramic glaze preparation, sintering of powder metallurgy, nano materials, metal parts quenching heat treatment and everything should be fast heating-up process requirement, is a scientific research units, universities and colleges, industrial mining enterprises ideal experiments and production equipment.

Safe operation

1.Vacuum heat treatment furnace is an advanced heat treatment equipment developed greatly in recent years. The workpiece is heated and cooled in the space of ultra-low pressure. It has the advantages of good quality, energy saving, safety and less pollution.

2.The heating element of the vacuum furnace uses low voltage electricity, but the power supply voltage is still 380V, so it still needs safe electricity during operation.

3.vacuum furnace manufacturing, should ensure no air leakage, water leakage. The sealing of the vacuum furnace body and cover is made of rubber, so it needs to be cooled by water insulation. If water leaks into the furnace, the temperature in the furnace is very high and it will cause an explosion. The workpiece processed by the vacuum furnace should be cleaned of oil stains on the surface, and the oil vapor from the quenching oil groove should be avoided from entering the furnace. These oil vapors will mix with air to form an explosive atmosphere, which will explode when there is an open flame or electricity. Therefore, the furnace door should be closed after the vacuum furnace is loaded, and the furnace can be pumped into a vacuum before electrifying heating.

Product features

The water cooling device, the shell and cover of the vacuum heat treatment furnace, the conductive treatment of the electric heating element (water-cooled electrode), the middle vacuum insulation and other parts, all work under the vacuum and heating state. Working under such adverse conditions, it is necessary to ensure that the structure of each component is not deformed or damaged, and the vacuum sealing ring is not overheated or burned. Therefore, water cooling devices should be set up for each part according to different conditions to ensure that the vacuum heat treatment furnace can run normally and have enough service life.

Low voltage and high current: in the vacuum container, when the true emptiness is within a certain range, the energized conductor in the vacuum container will produce glow discharge phenomenon under a higher voltage. In vacuum heat treatment furnace, arc discharge will be produced seriously, which will burn electric heating element, heat insulation layer and so on, resulting in serious accidents and losses. Therefore, the working voltage of the electric heating element of the vacuum heat treatment furnace is generally not more than 80-100 volts. At the same time, effective measures should be taken when designing the heating element structure, such as avoiding the parts with tip as far as possible, and the distance between electrodes should not be too narrow to prevent glow discharge or arc discharge.

Most heating and heat insulation materials can only be used in vacuum: the heating and heat insulation lining materials of vacuum heat treatment furnace work in vacuum and high temperature, so the requirements of high temperature resistance, low steam pressure, good radiation effect and small thermal conductivity of these materials are put forward. Resistance to oxidation is not high. Therefore, tantalum, tungsten, molybdenum and graphite are widely used as heating and heat insulation materials in vacuum heat treatment furnace. These materials are easily oxidized in the atmosphere and therefore cannot be used in conventional heat treatment furnaces.

Strict vacuum sealing: it is well known that vacuum heat treatment of metal parts is carried out in a closed vacuum furnace. Therefore, it is very important to obtain and maintain the original leakage rate of the furnace and ensure the vacuum degree of the vacuum furnace to ensure the quality of vacuum heat treatment of parts. Therefore, a key problem of vacuum heat treatment furnace is to have a reliable vacuum sealing structure. In order to ensure the vacuum performance of the vacuum furnace, a basic principle must be followed in the structural design of the vacuum heat treatment furnace, that is, the furnace body should adopt gas-tight welding, and at the same time, the furnace body should be opened or not opened as little as possible, and the dynamic seal structure should be used less or avoided 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, must also be designed with a sealed structure.

High degree of automation: The degree of automation of vacuum heat treatment furnace is high, because the heating and cooling of metal workpiece need more than a dozen or even dozens of actions to complete. These actions are carried out inside the vacuum heat treatment furnace, inaccessible to the operator. At the same time, some actions such as heating and insulation after the end of the metal workpiece quenching process must be six actions and to be completed within 15 seconds. In such a rapid condition to complete many actions, it is easy to cause the tension of the operator and constitute a misoperation. Therefore, only a high degree of automation can be accurate and timely according to the program coordination.

Equipment selection: VOGQ series vacuum heat treatment furnace produced by SIMUWU company is a high quality product for vacuum heat treatment process of tools and molds. Good temperature control precision and temperature control uniformity ensure the effective process of vacuum heat treatment. SIMUWU company focuses on vacuum furnace manufacturing, has more than 10 years of related experience, in the field of vacuum furnace manufacturing has a good reputation. The product line includes true air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., widely sold in developed and developing countries.