Vacuum Heat Treatment Technology Development

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Vacuum heat treatment processing technology mainly refers to the combination of vacuum technology and heat treatment technology of the new heat treatment technology, among them, vacuum heat treatment in vacuum environment refers to the below an atmospheric pressure of the atmosphere environment, including the low vacuum, the medium vacuum, high vacuum and high vacuum, etc., so, vacuum heat treatment also belong to the controlled atmosphere heat treatment.

Vacuum heat treatment means that all and part of the heat treatment process is carried out in vacuum.

Vacuum heat treatment can realize almost all the heat treatment processes that can be involved in conventional heat treatment, but the quality of heat treatment is greatly improved.

Compared with conventional heat treatment, vacuum heat treatment processing technology can achieve no oxidation, no decarburization, no carburizing, can remove the surface of the phosphorus chips, and have the effect of degreasing and degassing, so as to achieve the effect of surface brightness and purification.

1. Application of Vacuum Heat Treatment Technology

In fact, vacuum heat treatment processing technology was used earlier in foreign countries. In 1968, Hess Company of the United States and Japan Vacuum Research Institute successively developed vacuum quenching oil and water quenching medium. Thus, vacuum quenching technology has been rapidly developed in the heat treatment industry, from single-chamber furnace to multi-combination machine group.From the general vacuum quenching developed to high pressure gas quenching, vacuum water quenching, vacuum carburizing, vacuum carbonitriding and multiple co-infiltration.

In China, after decades of efforts, vacuum furnace manufacturers in the design, manufacturing level and quality has been greatly improved, with domestic vacuum equipment to replace the vacuum equipment imported from abroad gradually increased, thereby reducing the use of unit production costs, so that the scope of application of vacuum heat treatment rapidly expanded.

2. Process Principle of Vacuum Heat Treatment Technology

The thermodynamics and kinetics of solid phase transition are not changed in the vacuum with only 0.1MPa difference from atmospheric pressure.The principle of solid phase transformation under atmospheric pressure and the data of various types of tissue transformation under atmospheric pressure can be fully referred to in the formulation of the process rules of vacuum heat treatment.At the same time, the physical and mechanical properties of metal materials can be improved under the action of vacuum degassing. When heated in vacuum, the surface elements of metal workpiece will evaporate.The metal realizes the vacuum degree required by the heating without oxidation, the surface purification effect, and the realization of less oxidation and less stripping.

3. Characteristics of Vacuum Heat Treatment Technology

a. The Advantages of Vacuum Heat Treatment

Vacuum heat treatment is one of the most widely used non-oxidation heat treatment technologies, which goes hand in hand with controlled atmosphere. It is also one of the main symbols of the advanced degree of heat treatment production technology.Vacuum heat treatment can not only realize no oxidation, no decarbonization of steel, but also can realize no pollution and less distortion of the workpiece, so it also belongs to the scope of clean and precision production technology.At present, it has become an irreplaceable advanced technology in mold production.

b. Vacuum Heat Treatment Process Workpiece Distortion is Small

According to the experience at home and abroad, the distortion of the workpiece in vacuum heat treatment is only one third of that in salt bath heat quenching.It is of great significance for popularizing vacuum heat treatment technology to study the vacuum heating mode of various materials and parts with different complexity degree and the distortion law under various cooling conditions, and to simulate it by computer.When vacuum heating, atmospheric pressure or high pressure air cooling quenching, the uniformity of air flow has a great influence on the hardening effect and mass dispersion of parts. It is of great significance to improve the furnace structure to study the air circulation law in the furnace by computer simulation.

c. Vacuum Heat Treatment Furnace

Modern vacuum heat treatment furnace refers to a cold wall furnace which can carry out vacuum heating of components and then quench in oil or in atmospheric pressure and pressurized gas.Research and development of this type of device is a comprehensive, interdisciplinary work involving many fields of science and technology.

The application prospect of vacuum heat treatment for die materials is very great.Most die steels are currently heated in a vacuum and then cooled and quenched in a gas.In order to obtain satisfactory mechanical properties both on the surface and inside of the workpiece, vacuum high-pressure gas quenching technology must be adopted.At present, the international pressure of true air quenching has increased from 0.2MPa and 0.6MPa to 1-2MPa or even 3MPa. Therefore, the gradual increase of the cooling gas pressure of high-pressure gas quenching vacuum furnace is an important development trend.

Shanghai Geheng Vacuum Technology Co., Ltd. is a vacuum heat treatment furnace manufacturer with many years of experience in design, manufacturing and production. It mainly produces true air quenching furnaces, double chamber vacuum oil quenching furnaces, vacuum annealing furnaces, vacuum tempering furnaces , and other vacuum furnaces.

Editing by Frank Lee

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