Vacuum pressure sintering furnace

Vacuum pressure sintering furnace

In vacuum pressure sintering furnace this equipment, sintering material under high temperature is also subject to mechanical stress and the effect of vacuum, can be used in the sintering density after casting products. General powder material filling in the graphite mold, mechanical pressure by 700-1500 mn/m3, and heated to 2500 ℃ in the vacuum. Mold by direct current heating, indirect heating.
Vacuum pressure sintering furnace is mainly used for sintering is the density of the material with high temperature gas reactions billet, such as oxide, carbide and boride gas after sintering material can reach very high density, general density is greater than the theoretical value of 95%, and with high purity. Graphite resistor and graphite mould in the vacuum operation of weight loss is minimal. Vacuum hot pressing sintering is at the same time in the compaction process and utilization of high pressure, temperature and time, and many other parameters to control the quality of the sintered body.

The maintenance of sintering furnace

The maintenance of sintering furnace

1. The new furnace and lining refractories of replacement should be done after drying process. Oven to falling in to rise in stages. At the beginning of the dry, low temperature, long time, when the stove is cold by warming, furnace material of high moisture. In less than 400 degrees Celsius, to open the oven door discharge water vapor. When up to 700 ℃ heat preservation for a period of time. In order to make the temperature of the furnace body evenly.
, mesh belt furnace, the furnace temperature has risen to 400 ℃, shall run for a period of time, for oxidation treatment, improve the life of the net belt.
2. The low melting point impurity in the compact (S, Pb, zinc, etc) to the chamber of a stove or furnace material and heating elements are produces erosion, in order to improve the service life of the furnace, should be regularly purification furnace, presintering area, in particular, try to avoid in the powder metallurgy ingredients add S elements, such as to avoid pollution furnace and heating elements.
3. Regularly clean the stove, in using carbon monoxide or he carbon gases, could be breaking from the decomposition of hydrogen compounds to the carbon, this part of the carbon deposition on the furnace wall and heating elements, it will pollution stove, refractory erosion and damage the electric heating yuan
, so need to regular cleaning the stove.
4. Keep the body clean, regular cleaning furnace of iron oxide, gravel, zinc oxide and other debris.
5. Check the electric heating element and wire connection, prevent poor contact arc.
6. Due to the need of furnace operation under the low dew point, so the leak bolted flange sealed parts regularly
Detection.
7. Do not insert with grease tray in furnace, grease into Shanghai in one thousand will make a sharp increase in dew point affect normal operation.
8. The high temperature, don't play to open the door for a long time, in order to prevent the air into the furnace, damage the electric heating element.
9. No overtemperature operation.

The characteristics of the vacuum furnace temperature field formed

The characteristics of the vacuum furnace temperature field formed

Vacuum furnace heating elements generally assumes the circular layout. Relative average furnace, vacuum heating only the heat transfer of radiation, conduction and convection; The vacuum heat conduction, convection and radiation, three ways of convection and conduction depending on the pressure and with ordinary furnace (normal pressure).
Pressure is less than 1 x 105 pa (absolute pressure, ordinary furnace approximation of working pressure), the convection and conduction effect is less than ordinary furnace; Working pressure close to the vacuum (pa) 2, the convection and conduction effect basic does not exist, workpiece temperature is slow, especially below 600 ℃ heating, heating more slowly, the temperature of the workpiece temperature thermocouple temperature control has certain hysteresis.
The vacuum furnace temperature uniformity measurement is different from ordinary furnace, when measuring the need to guarantee the normal work of the furnace under the condition of vacuum and pressure rise rate, can correct determination of furnace temperature. Because, unlike ordinary furnace, vacuum furnace heat transfer of actual temperature measurement process shows that the control thermocouple temperature at the beginning of the heat preservation and the effective heating area measuring thermocouple temperature difference is bigger. In vacuum condition, temperature deviation in the normal heat preservation time of the effective heating area can reach + / - 5 ℃, meet the needs of the process.

Little knowledge of vacuum sintering furnace

Little knowledge of vacuum sintering furnace

Vacuum sintering furnace in the furnace chamber within a particular space using vacuum system (by the vacuum pump, vacuum measuring device and vacuum valve components such as carefully) substances out of furnace cavity part, making furnace chamber pressure is less than a standard atmospheric pressure, so as to realize a vacuum furnace cavity space, that is the vacuum sintering furnace.
1) completely eliminates the oxidation and decarburization on the surface of the workpiece during the process of heating, clean surface without metamorphic layer can be obtained. That only when grinding mill side of cutting tools (such as twist drill grinding after make direct exposure to edge) of the decarburization layer of the grooved surface cutting performance greatly improved relations.
2) on the environment pollution-free, "three wastes" treatment is not required.
3) obviously improve the temperature measurement, the monitoring precision. Indicated value of thermocouple temperature and furnace temperature reached plus or minus 1.5 ° c. But in different parts of a large number of artifacts in the furnace temperature difference is bigger, if USES the rarefied gas forced circulation, can still be controlled within + / - 5 ° c temperature difference.
4) high degree of mechanical and electrical integration. Increase in the temperature measurement and control accuracy, on the basis of the workpiece moving, pressure adjustment, power adjustment, etc all can set programming in advance, according to the steps to implement the quenching and tempering. 5) energy consumption significantly below the salt bath furnace. Modern advanced vacuum furnace heating chamber is made of high quality insulation material of insulation walls and barriers, electric energy can be highly focused on indoor heating, energy saving effect is remarkable.