Stress relief annealing of the UI Lamination For Transformer Iron Cores

- Mar 10, 2019-

The UI Lamination  For Transformer Iron Cores to be annealed is laminated into an iron box, and the frame is placed. Each box of steel sheets is covered with a cover plate slightly smaller than the iron box, and is hung in the furnace to lock the furnace cover. Install the three thermocouples on the furnace, install the chimney, and open the exhaust valve. Check the voltage, current, and meter of the electrical cabinet. Install the recording paper and check the normal paper feed of the recording paper.


Set the initial temperature of the temperature control table to 400 °C, check whether the currents of the power meter are the same. After ensuring the adjustment, turn on the heating switch to heat. Check the normality of the meter in the electric house and adjust the power of the furnace. Connect the nitrogen, check for leaks, and check the normal supply of circulating water.


When the temperature was raised to 400 ° C, the nitrogen nitrogen valve was opened, and 100-200 ml of nitrogen was injected, at which time the valve for circulating water was opened. When the temperature is determined to rise to 400 ° C, the temperature is kept constant, and the temperature is kept for about 1 hour. After the temperature is maintained, the temperature control table is set to 500 ° C and heated.


When the temperature is raised to 500 ° C, the temperature is kept for about 45 minutes. After the temperature is completed, the temperature control table is set to 600 ° C to perform heating. The nitrogen pressure regulating valve is adjusted to be large, and 200-400 ml of nitrogen gas is injected, and at this time, the exhaust gas is large. When the temperature rises to 600 °C, the temperature is about 45 minutes. At this time, see if the voltage is normal. Finally, the temperature control table is set to 680 ° C - 750 ° C, nitrogen can be opened larger, or maintain 400 ml of nitrogen, at this time more exhaust.


After the temperature rises to the set temperature, the constant temperature time should not be less than 2 hours. After the end, the exhaust valve is closed, the nitrogen gas is injected at 100-200ml, the circulating water valve can be closed, and the heating switch and the power switch are turned off. After the inspection is correct, the UI core of the transformer core is subjected to a stress-relieving annealing process to enter a natural cooling state, and the furnace temperature can be lowered when the temperature falls below 380 °C.