The main process equipment of the annealing furnace includes an annealing furnace with a feed pipe and a discharge pipe, an inner cover, a heating cover, a cooling cover, and a valve station. At the beginning of annealing, the steel coils to be annealed should be stacked on the annealing furnace, the inner cover should be lifted, and a cold seal test should be performed on the furnace, inner cover system, and hydrogen inlet valve.
After the test is successful, it needs to be tested. Perform a nitrogen purge while lifting the heating mantle, then ignite the heating mantle.
When the nitrogen purge meets the conditions, replace the nitrogen in the inner cover with hydrogen purge. Start heating, and select the heating curve according to different materials for temperature control, until the temperature of the coil core meets the process requirements.
We can think that the main reason for the uneven heating of the aluminum coil is the way the aluminum coil is placed in the furnace, so we try to research a scientific way of placing the aluminum coil so that the aluminum coil can be heated evenly when it is heated by the hot air.
Placement of Aluminum Coils in the Annealing Furnace:
After research, it is found that because aluminum coils are similar to pie-shaped metal blocks, their side areas are small, and the main contact with the air is the upper surface and the lower surface, so we let the aluminum coils The placement of the coils is not placed flat in the furnace, but many aluminum coils are placed vertically in the furnace, so that the hot air first touches the side of the aluminum coils, and then the hot air continues to move upwards along the upper and lower surfaces of the aluminum coils.
On the other hand, since the aluminum coil is in the shape of a round cake, placing it vertically will allow the hot air to flow more along the side arc of the round cake, and will allow the hot air to contact the surface of the aluminum coil more. After the above improvements, most of the surface of the aluminum coil will be in direct contact with the flowing hot air, so its heating will be more uniform, and the mechanical properties of the aluminum coil after production will be more stable.
On the other hand, we learned that the horizontal placement of aluminum coils in the previous furnace took into account uniform heating, so the placement of aluminum coils in the furnace will be relatively sparse. A large increase in the heating temperature difference of the aluminum coil, and the temperature difference of the aluminum coil in different positions will also be very large.
After the improvement, the aluminum coils can be placed vertically, which greatly increases the number of aluminum coils that can be placed in the furnace at the same time. We generally believe that about one-third more aluminum coils can be placed in the furnace after the improvement. Roll, and the heat will be much more even.
Matters Needing Attention in the Use of Annealing Furnace
The temperature of the furnace should not exceed 650°C.
When the furnace temperature exceeds the temperature limit, it is necessary to manually cut off the air switches of the four thyristor AC power units. After the alarm signal disappears (after troubleshooting), the air switches need to be manually closed to resume automatic operation.
Do not cut off the power, disconnect the power supply, or do other operations when the furnace is working.
The workpiece is placed in the correct position on the feeding cart, and it cannot be skewed, let alone exceed the periphery of the material rack. Fan bearings, furnace door opening mechanism bearings, and feed car bearings must be regularly filled with lubricating oil.
Regularly check the wiring of each component, especially the wiring of electric heating elements, thermocouples, and travel switches. Regularly check the working conditions of all valves, piping systems, and electrical systems.
