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.