On 2018-08-08 14:48:54
Analysis of advanced heat treatment technology
1. Controlled atmosphere heat treatment
Controlled atmosphere heat treatment is mainly to prevent oxidation and decarburization, and to achieve accurate control of carburizing and nitriding. In the late 1980s, it began to be used in industrial production. Up to now, its development speed and wide application are amazing.
2. Vacuum heat treatment
Salt bath quenching is limited by the environment, and it has become a sunset. The application and development of vacuum heat treatment technology has been further improved and promoted. It has the characteristics of no oxidation, no decarburization, clean and bright surface of workpiece after quenching, high wear resistance, no pollution and high degree of automation. Vacuum annealing, vacuum degassing, vacuum oil quenching, vacuum water quenching, vacuum gas quenching, vacuum tempering and vacuum carburizing are widely used in industrial production. In recent years, with the appearance of high-pressure gas quenching vacuum furnace, the vacuum quenching of high-speed steel tools has become a reality.
3. Induction heat treatment and ion nitriding heat treatment technology
Induction heat treatment is widely used in automobile industry, engineering machinery, petrochemical industry and other industries with the advantages of high efficiency, energy saving, cleaning and flexibility. Nearly 40% of automobile parts can be treated by induction heat treatment, such as crankshaft, gear, universal joint, half shaft, etc. With induction heating, many products can be processed into full-automatic or semi-automatic production lines to improve the stability of product quality, reduce labor intensity and beautify the working environment. Induction heating power supply is the fastest growing power supply in China. The old electronic shock tube has completed its historical mission and replaced by full transistor. The microcomputer controlled transistor is used to adjust the power supply, which is stable and convenient, with high precision, and greatly reduces the interference to the harmonic of the power grid.
4. Quenching medium and cooling technology
The ideal quenching medium should have the following characteristics:
(1) quality type: fast cooling in high temperature stage, slow cooling in low temperature stage. That is to eliminate cracks and reduce quenching deformation.
(2) Environmental protection type: no toxic, harmful smoke or gas volatilization, not easy to burn, easy to clean after quenching, no corrosion to the equipment, no stimulation to burn skin.
(3) Stable type: after quenching, the performance of the workpiece is even and stable, and the medium itself is stable in a certain period of time.
(4) Economic type: high quality and high price, low energy consumption.
In recent years, the development of quenching medium is very rapid. The properties of quenching oil have been improved, and the research and application of organic polymer quenching medium have reached unprecedented development.
5. Adopting new surface strengthening technology and popularizing heat treatment of nitrogen based atmosphere
The original tool surface treatment method is only limited to steam treatment, oxygen nitriding and other old methods, which can only improve the tool life by 30% ~ 50%. Since 1980s, China has independently developed and imported QPQ salt bath composite treatment technology and PVD titanium oxide physical coating technology from abroad. The former can steadily increase the tool life by 2-3 times, the equipment is simple and the cost is low, so it is especially suitable for ordinary cutting tools; the latter can increase the tool life by 3-5 times, which is suitable for all kinds of precision and valuable gear cutting tools.
Nitrogen based atmosphere, used for protecting heat treatment and chemical heat treatment, can realize non oxidative decarburization heat treatment, and can avoid nitrogen embrittlement of heat treatment. Nitrogen based atmosphere chemical heat treatment can reduce internal oxidation and other defects, and improve the quality of chemical heat treatment.