1、 Load the silicon steel sheets to be annealed into an iron box (according to the size of the silicon steel sheets, pay attention not to exceed three layers) and the loading rack. Each box of silicon steel sheets should be covered with a cover plate slightly smaller than the iron box (preferably made of silicon steel sheet material). Lift it into the furnace, lock the furnace cover, tighten the sealing ring, and connect the circulating water pipe.

2、 Connect the nitrogen gas, check for any leaks, and verify the normal supply of circulating water.

3、 Close all valves, install vacuum tubes, turn on the vacuum pump, open the vacuum valve, evacuate to -1MPA, close the needle valve tightly, and then close the power supply of the vacuum pump.

4、 Connect the nitrogen pipe to the inflation valve, open the inflation valve, and inject nitrogen gas. Close the inflation valve and open the safety valve when the pressure is between 0.03 and 0.1MPA

5、 Install the three thermocouples on the furnace body,

6、 Check if the voltage, current, and appearance of the electrical cabinet are normal,

7、 Set the initial temperature of the temperature control meter to 400 ℃, check if the currents on the power meter are consistent, and after ensuring consistency, turn on the heating switch to heat up. At this moment, open the valve of the circulating water to ensure that there is no blockage and the water flow is unobstructed.

8、 Check if the exterior of the electrical room is normal and adjust the power of the annealing furnace.

9、 When the temperature rises to 400 ℃, open the nitrogen filling valve (smoke exhaust) and close the filling valve when the gas is released to 0.01MPA. Repeat the operation of steps three and four

10、 When the temperature is confirmed to have risen to 400 ℃, maintain a constant temperature for about 1 hour [approximately the time of the ninth operation], and confirm that the external temperature is also around 400 ℃.

11、 After the insulation is completed, set the temperature control meter to 680 ℃ and heat it up,

12、 During heating, pay attention to the flow rate and temperature of the circulating water, and the pointer of the pressure vacuum gauge should not exceed 0.1MPA; If the pressure exceeds 0.1MPA, the inflation valve should be opened for deflation, and it should always be kept at 0.1MPA

13、 The temperature control meter is set to 680 ℃~750 ℃

According to the raw materials of silicon steel sheets, cold-rolled non oriented silicon steel sheets with low trademark domestic BS0A600, 50W600, 50WW540 and below generally have an annealing temperature of around 680 ℃, while the same raw materials can be appropriately annealed at 20 ℃. Non oriented high trademark generally have an annealing temperature of around 720 ℃.

14、 After the temperature rises to the set temperature, the constant temperature time should not be less than 2 hours, and the appearance should also be above or below the set temperature.

15、 After completion, close the heating switch and power switch.

16、 After checking for accuracy, the stress relief annealing process of the silicon steel sheets in the furnace enters a cooling state. When the temperature inside the furnace drops below 380 ℃ (preferably 350 ℃), the vent valve is opened to release the gas. After blackening treatment, compressed air should be filled into the furnace for 5 minutes. The furnace cover should be opened before being discharged from the furnace. Lift the material rack out and place it in a safe position, then use an electric fan to blow air in a tangential direction until it cools to the desired temperature. At this point, the circulating water valve can be closed (the outlet valve is always open), and countries classify trademarks based on iron loss values. The lower the iron loss, the higher the trademark.

Article source: Transformer silicon steel sheethttp://www.cheungshun.com/