Vacuum heat treatment technology

    The rise and rapid development of vacuum heat treatment technology, on the one hand, stems from the needs of industrial technology development, and on the other hand, because vacuum heat treatment has a series of outstanding advantages that are incomparable with other heat treatments. These advantages are:

    (1) Prevent oxidation, the surface does not oxidize, decarburize, and has the effect of reducing and removing rust, eliminating the surface grinding process, thereby saving steel and raw materials consumption, and saving processing time;

    (2) The vacuum degassing effect improves the surface purity of the material, improves the fatigue strength, plasticity and toughness of the material, and improves the corrosion resistance;

    (3) Degreasing function to remove residual grease and improve product quality;

    (4) There is no risk of hydrogen embrittlement when processing the workpiece, and the embrittlement of the surface of titanium and refractory metals is prevented;

    (5) The quenching deformation is small. Because the vacuum heating is slow, the temperature difference between the inside and the outside of the workpiece is small; the thermal stress is small; the vacuum heating process generally preheats 1 to 2 times, and the temperature difference of the workpiece section is small; the insulation system and heating elements of the vacuum heating chamber are designed and arranged reasonably, and the heating is uniform; at the same time, the vacuum furnace The structure is designed so that the workpiece has no violent transfer action, so it will not be deformed due to external force. Generally speaking, the deformation of vacuum heat treatment workpiece is 1/2~1/10 of salt bath quenching;

    (6) Compared with the controllable atmosphere furnace, it does not need a high-quality combustible gas source and saves energy. Because the vacuum heating chamber uses materials with small specific heat capacity and good heat insulation effect as the heat shield, the heat storage loss is small, and the furnace High thermal efficiency, which can achieve rapid heating and rapid cooling;

    (7) The stability and repeatability of the vacuum heat treatment process are good;

    (8) Low power consumption, energy consumption is 50% of conventional heat treatment, low production cost;

    (9) Safe operation, high degree of automation, good working environment, pollution-free and pollution-free. Vacuum heat treatment also has shortcomings and shortcomings, and corresponding measures are taken to prevent and avoid them in practice. The main disadvantages are:

    (1) Certain alloys and elements evaporate greatly in vacuum and should be avoided. Inert gas is used for heating protection during production;

    (2) Vacuum heat treatment equipment has a large one-time investment, but as long as the task is full, the investment can be recovered in a relatively short period of time (1 to 2 years).

(Huiputech)