Vacuum heat treatment furnace is an important equipment to realize vacuum heat treatment. The air pressure in the furnace is lower than normal air pressure. The atmosphere in the furnace is equivalent to a kind of gas, which can prevent the heat treatment from oxidizing. The vacuum treatment furnace has a wide range of uses, mainly used for vacuum tempering, aging, annealing, and quenching of structural steel, stainless steel, heat-resistant alloys, precision alloys and materials. It can also be used for vacuum degassing, brazing and sintering, etc. aspect.
1. The choice of vacuum furnace should be based on the chemical composition and heating temperature of the parts to be heat treated. It must meet the relationship between the equilibrium decomposition pressure of metal oxides and carbon monoxide, and a certain amount of room must be considered. Do not pursue a high degree of vacuum. Excessive vacuum will not only cause alloying elements. The volatilization will also increase the configuration of the equipment and increase the investment cost.
2. Cooling type The cooling of the vacuum furnace has oil cooling and air cooling. At present, air-cooling is mainly used because air-cooling has no pollution and adverse effects on heat-treated parts. Oil cooling has surface micro-carburization problems and affects quality. After treatment, the surface of parts is clean and does not need to be cleaned. Therefore, air-cooling is generally used when the cooling rate is satisfied. Cold quenching is the first choice. The cooling speed of air-cooling is mainly affected by factors such as air pressure, flow rate, and the form and distribution of airflow. A comprehensive consideration should be given to the selection. Generally speaking, the air pressure is high, the flow rate is large, and the cooling rate is fast, that is, the cooling rate is directly affected by the air pressure and the flow rate. In addition, the flow rate of the heat exchanger cooling water during air cooling has a significant impact on the actual cooling. We realize that the cooling speed will be significantly faster when the cooling water flow is larger than the cooling water flow under the same air pressure and flow conditions.
3. Heating element form There are certain differences in the form and material of the heating element of the vacuum furnace. Generally, the plate type and the rod type are multi-materials for high-quality graphite. In recent years, the emergence of CFC carbon-carbon composites has shown greater technical advantages and tends to replace graphite. In the case of the same power, the thinner CFC material is relatively small for heat storage, which is beneficial to increase the cooling rate.
4. Function purchase furnace should consider the versatility of the process, that is, the temperature range of quenching and tempering should be wide. In particular, it is very convenient to handle high-alloy steels with high tempering temperature and directly tempering without leaving the furnace after quenching.
5. Control system The control system is the core part of the vacuum heating furnace to ensure its reliability and completeness. It is extremely important. It is best to have monitoring and fault display and recording functions. Imported equipment needs to be equipped with remote monitoring functions. This can ensure the timeliness of fault handling and reduce certain maintenance costs.
6. Other tightness and reliability of vacuum system configuration are also important links. When modeling equipment, it must not be complicated in form and must be reliable on the basis of comparison.