Vacuum oven: purpose, technical characteristics

Technological processes of production and processing of various materials often include the stage of passing the thermal action. Thus hardening, drying at high temperatures, soldering and other procedures are performed. It is not always possible to implement such measures in conventional furnaces, even for industrial purposes. Restrictions may be related to the inadmissibility of contact with the air environment. Therefore, to solve such problems, a vacuum furnace is used, processing in which also excludes the processes of excessive deformation and warpage of blanks.

Purpose and scope of application of vacuum furnaces

Thermal firing operations in vacuum are used in machine-building and instrument-making, in the construction industry, in various industries, etc. For example, in the instrument-making industry, with the help of such an aggregate, an operation of degassing of the elements is performed, which later become components of various equipment. In the same direction, the vacuum oven allows high-quality soldering and finishing of individual areas on electrical boards.

The operation of sintering is also common. With its help in construction and production, necessary performance qualities are given to ceramic products, solid alloys, refractory metal powders, etc. The metallurgical industry is also worth noting, which is also interested in heat treatment operations. For example, a vacuum oven allows the implementation of procedures for hardening, aging and tempering of alloys. Such treatments can be exposed to various steels, bronze and magnesium.

Main technical characteristics

The performance of the furnace structure often becomes the main criterion for choosing a model. In this case, the installation has a potential of 3 to 20 kW. And the quality and efficiency in the provision of thermal exposure, this indicator affects to a minimum. As a rule, the power increases as the load volume increases, which depends on the size of the structure. So, in standard industrial models of this type, you can load from 15 to 40 kg of material on average. But there are also aggregates that allow you to service up to 100 kg at a time. The induction melting furnace, equipped with average characteristics, is able to service up to 9000 kg per shift. With regard to the quality and effectiveness of exposure within the chamber, the immediate temperature range should be taken into account. It is from 1800 to 2000 ° C.

Process of smelting

Technology in traditional aggregates is based on the action of an arc discharge. There is a contact of an electric current and a gas mixture. Further, the resulting arc due to a high concentration in a vacuum provides an increased thermal effect. Even at low power, the vacuum-arc furnace is able to melt the steel preforms.

There are two principles of heat transfer in relation to the material. This is a direct and indirect effect. In the first case, the arc forms the energy between the electrode and the workpiece, which in this configuration receives a maximum of heat. Indirect heating involves working with two electrodes, which at some distance affect the object. It is obvious that a vacuum furnace with direct heat transfer is more efficient, but it allows a greater percentage of negative heat treatment factors.

Types of furnaces

The basic model of the vacuum furnace structure is the above-described arc structure. With the help of such equipment, it is possible to service most varieties of complex metal alloy, including refractory products. Another type is an induction melting furnace, in the device of which an inclined crucible is provided. Just in the crucible and the process of melting material, loaded into the working chamber, is realized. The induction principle of operation is considered to be the most expensive in service, therefore it is used less often and only when it is necessary to work with complex metals. A special type of vacuum furnace is the electron-beam unit. Such a device produces purified alloys and metal ingots at the outlet. Structurally, the equipment is a thermal gun, which, through directional action, implements a radiation firing of the product.

Advantages and disadvantages of vacuum furnaces

Compared to conventional heat treatment furnaces, vacuum allows a highly effective thermal effect on the workpieces. In this case, the operator has the flexibility to adjust the heating parameters, which, for example, provides a vacuum induction furnace with a crucible. The merits of such designs include the possibility of obtaining a relatively pure metallic material. That is, the technology itself eliminates the excessive contamination of the massif with foreign particles - heat treatment products.

As for the shortcomings, they are associated with a low resource of the parts that form the structure. It's not even the flaws in the material of the constituent elements, but in the harsh conditions that are required to ensure a productive heat treatment and which affect the structure of the working surfaces. In addition, a vacuum oven, whose average price is 500-700 thousand rubles, is available to a few enterprises. Yet the high quality of sintering and melt is an expensive way of limiting its use.

Manufacturers

The supply of vacuum furnaces is handled only by large enterprises cooperating with the institutes of designing and developing industrial equipment. Today, high-quality aggregates of this type are supplied to the domestic market by foreign manufacturers SCHMETZ and XERION. This product is oriented to the performance of typical thermal operations, and to specialized tasks like diffusion annealing. The Moscow factory of the industrial equipment specializing on release of vacuum electric furnaces, also offers worthy on characteristics units. With the help of such equipment, the owner can carry out the release of metal, sintering and standard thermal processes. Automatic model offers "Zavod Spetszhelezobeton", which develops high-vacuum units with volumetric loading chambers.

Conclusion

An example of vacuum annealing technology shows that not always new solutions justify themselves in the process of operation. Although the same Moscow plant of industrial equipment seeks to optimize the units for the needs of a wide range of consumer enterprises, the high cost of vacuum heat treatment processes for many potential customers makes this method inaccessible. Refusal of such furnaces is caused not only by their cost, but by absence of necessity of reception of a high-quality product. Nevertheless, advanced companies working in high-tech industries can no longer do without using such heat treatment facilities.