On 2018-08-08 14:48:54
How to choose vacuum heat treatment furnace
How to choose vacuum heat treatment furnace is no longer difficult from these six aspects!
The vacuum heat treatment furnace can realize the heat treatment of materials. The advantage of the utility model is that the air pressure in the furnace is lower than the normal air pressure, and the atmosphere in the furnace is equivalent to a kind of gas, which can prevent the heat treatment from oxidation. Heat treatment equipment is widely used, mainly for structural steel, stainless steel, heat-resistant alloy, precision alloy and material vacuum tempering, time, annealing, quenching, also can be used for vacuum degassing, brazing and sintering. The vacuum heat treatment furnace can be used safely and reliably, can realize automatic operation, and has no pollution and public hazards.
The selection of high temperature vacuum furnace mainly starts from six aspects:
When purchasing equipment for high temperature vacuum furnace, the universality of technology should be considered, that is, the range of quenching and tempering temperature should be wide. It is very convenient to process high alloy steel with high tempering temperature and direct tempering after quenching.
2. Control system
The control system is the core part of the vacuum heating furnace to ensure its reliability and perfection. It has the functions of monitoring, fault display and recording. For imported equipment, it needs to be equipped with remote monitoring function, which can ensure the timeliness of fault handling and reduce the fixed maintenance cost.
3. Composition of material
The selection of vacuum equipment of high temperature vacuum furnace should be realized according to the chemical composition of the parts to be heat treated and the heating temperature. The relationship between metal oxide and the decomposition pressure of carbon oxide must be satisfied, and certain space should be considered. Do not excessively pursue high vacuum. High vacuum will not only cause the volatilization of alloy elements, but also increase the equipment configuration and investment cost.
4. Heating element form
The form and material of heating element of high temperature vacuum furnace are different. It is mainly plate and rod type, and the material is high-quality graphite. In recent years, the appearance of CFC composite shows great technical advantages and tends to replace graphite. With the same power, the thickness of CFC material is thin and the relative heat storage is small, which is beneficial to improve the cooling rate.
5. Cooling form
The cooling of high temperature vacuum furnace includes water cooling, oil cooling and air cooling. At present, it is mainly air-cooled, because the air-cooled parts have no pollution and adverse effects on the heat treatment. The surface of the parts after treatment is clean and does not need to be cleaned, so the air-cooled quenching is generally used as the choice under the condition of satisfying the cooling speed. The cooling speed of air cooling is mainly affected by the air pressure, flow rate, the form and distribution of air flow and other factors, which should be considered in the selection. In general, high air pressure, high flow rate and fast cooling speed are directly affected by air pressure and flow rate.
In addition, the flow rate of cooling water has a significant impact on the actual cooling. Under the same air pressure and flow conditions, the cooling speed of the larger cooling water flow is obviously faster. The uniformity of cooling is very important. Some vacuum furnace nozzle distribution design is not considered enough. It is found that there is a significant difference in cooling speed when no air jet nozzle is set near the furnace door, especially when large parts are treated, which leads to insufficient quenching and poor uniformity.
Sealing and reliability of vacuum system configuration are also important links. Equipment selection should not be complicated in form, but reliable on the basis of comparison. Some furnace doors are not rigid enough in design. The use process combined with the sealing part will produce an imperceptible displacement, which will affect the sealing results. The leakage rate will increase, and the load of vacuum pump will be increased invisibly. The actual utilization rate of the equipment will be significantly reduced.
In addition to the above factors, the use of different vacuum heat treatment furnaces should also be considered. For example, the vacuum sintering furnace is mainly used for w-based cemented carbide sintering, hydrogen storage material annealing, permalloy sintering and annealing; the vacuum water quenching furnace is mainly used for austenitic stainless steel solid solution beryllium bronze solid solution, nuclear industry special material and other solid solution, water quenching and concurrent annealing functions; the vacuum oil quenching furnace is mainly used for alloy structural steel, various tool steel quenching austenitic stainless steel solid solution and concurrent annealing Functions and so on. When choosing, we should choose according to our own needs, and choose the right one to reflect the effect of vacuum heat treatment furnace.