On 2018-08-08 14:48:54
Tool vacuum heat treatment technology
The cold wall vacuum heat treatment furnace with oil and gas quenching and cooling was developed in 1970s and produced in series in 1980s. At present, local manufacturing enterprises have been able to provide a series of vacuum heating, oil-gas quenching furnace, low-pressure carburizing furnace, 1MPa (10bar) high-pressure gas quenching furnace, vacuum sintering furnace, and brazing furnace. The highest temperature of vacuum quenching and high pressure gas quenching furnace can reach 1350 ℃, and the highest temperature of vacuum sintering furnace can reach 1800 ℃.
The output of various kinds of furnaces and furnace types is more than 200. In recent years, the development of aviation industry and mold industry has a great demand for vacuum heat treatment furnace, vacuum brazing furnace, especially for vacuum heating high-pressure gas quenching furnace, which promotes the prosperity of vacuum equipment manufacturing industry. The combination of low-pressure carburizing and high-pressure air quenching technology provides a new way for prolonging life, reducing distortion (deformation) and noise reduction of vehicle gears, and the development of semi continuous production line embodying this advanced technology provides the possibility for the technical transformation of heat treatment of automobile gears in mass production. At the beginning of the new century, several domestic automobile and diesel engine gear manufacturers have introduced such equipment and production lines.
Due to the high requirements of die surface quality and distortion, vacuum high-pressure gas quenching has almost become an irreplaceable technology of die heat treatment. At present, in South China and East China coast, private heat treatment and processing enterprises with a small scale have at least one 0.4MPa (up to 6) vacuum heating high-pressure gas quenching furnace. In the cutting tool industry, with the wide application of numerical control and machining center, it is strongly required that the cutting tool has high quality and long service life, and the environmental protection of the city also puts forward more strict requirements for heat treatment. Therefore, vacuum heating and high-pressure air quenching has become the preferred process of high-speed steel tool heat treatment instead of salt bath heating and quenching.
In order to meet the strict requirements of international environmental protection standards, the concept of circular economy of comprehensive utilization of wood and continuous supply of raw materials has promoted the rapid development of wood processing industry. Therefore, the Research Institute of Rizhao Longte mechanical cutting tools has developed the vacuum heat treatment and deep cooling technology of woodworking cutting tools. The technology has been applied to the cutting tools of Longte machinery, and will appear in the 12th International Woodworking Machinery and furniture production equipment exhibition, the 12th International Furniture accessories, materials and woodwork exhibition.
The technology of tool vacuum heat treatment has a series of outstanding advantages
Vacuum heat treatment can prevent oxidation. The surface is not oxidized, decarburized, and has the function of reducing and derusting, which saves the rough machining process of the tool, saves the consumption of expensive tool steel and raw and auxiliary materials, saves the processing time and reduces the product cost;
Vacuum heat treatment has the function of vacuum degassing and degreasing without danger of hydrogen embrittlement. It can prevent the surface embrittlement of the refractory metal of the tool material, improve the surface purity of the tool material, improve the fatigue strength, plasticity, toughness and corrosion resistance of the tool, and improve the service life of the tool;
Vacuum heat treatment has small quenching deformation, which can reduce the existence of correction stress of conventional quenching deformation and reduce the possibility of fracture during the use of the blade. The deformation of vacuum heat treatment blade is 1 / 2-1 / 10 of that of salt bath quenching. After quenching, it can be grinded to the finished product without correction;
The vacuum heat treatment process has good stability and repeatability. Once the process is determined, the heat treatment operation will run automatically as long as the process program is input. Avoid the tool quality fluctuation caused by the instability of conventional heat treatment process;
The power consumption of vacuum heat treatment is less, 80% of that of conventional heat treatment. The production cost is low, but the one-time investment cost is large;
The operation of vacuum heat treatment is safe, highly automatic, good working environment, pollution-free and pollution-free, which meets the requirements of cleaner production and sustainable development of industrial enterprises in China.
The application of deep cooling technology in tool products has evolved from the application of mold industry. Like heat treatment, cryogenic treatment has a lot to do with material properties, treatment temperature and treatment speed. Different treatment methods have different effects. Cryogenic technology is a kind of processing method to treat the material below - 130 ℃. Cryogenic treatment can not only significantly improve the mechanical properties and service life of the tool, stabilize the size, improve the uniformity and reduce the deformation, but also operate easily, without damaging the workpiece, without pollution and low cost, which is very helpful to improve the quality of the tool.