The process of testing the uniformity of vacuum furnace temperature

1. According to the requirements of the vacuum brazing process, select the measurement temperature points at 650℃, 850℃ and 1000℃, and set the heating curve on the FP23 temperature control instrument.

2. After the control couple reaches the set temperature for 120 minutes, start to measure the value of each thermocouple. Read once every 5 minutes, 3 times in a row. If the temperature of each point is within ±5℃ of the required temperature, the measurement of this temperature point is completed, otherwise continue to be isothermal until the temperature is uniform or the time reaches 3h (the heat preservation set by the process) Time) and record the temperature at each point.

3. Adjust the FP23 meter, increase the temperature from 650°C to 850°C, keep the temperature for 120 minutes, and repeat the 650°C temperature point measurement procedure. Similarly, the temperature is increased from 850°C to 1100°C, the temperature is kept for 120 minutes, and the temperature point measurement procedure is repeated at 650°C.

4. Fill in the above data in the record table respectively. After the measurement is completed, follow the normal empty furnace cooling step to cool down.

5. After cooling down, open the furnace door, pull out the measuring bracket, disassemble the iron wire fixing the thermocouple, remove the flange, install the original cover plate, and perform the pressure rise rate test according to normal use.

6. Manually start the vacuum mechanical pump and vacuum Roots pump to pump the vacuum according to the operating rules, until the working vacuum reaches 2Pa, stop for 30min, observe the reading of the vacuum gauge, and see if the pressure rise rate is within the normal 0.5Pa/h. If it is qualified, continue, and the equipment can be used normally, otherwise continue to reinstall the original temperature measurement port cover.