Brief Introduction of Annealing Procedure for Packaging Steel Belt Bell Furnace

Brief Introduction of Annealing Procedure for Packaging Steel Belt Bell Furnace
The annealing procedure of the bell-type furnace is shown in Figure 4-12. The specific process is as follows:
　　 (1) Receiving, batching and charging. When receiving materials, check and verify the incoming materials. If there are loose rolls, center blockages, etc., they must be dealt with in time. When batching, the same process, same specification, same inner diameter, and same steel type should be put in one furnace. When the steel coil specifications are different, the ingredients should be prepared according to the principle of thin upper and thick lower, narrow upper and wide lower, and large upper and lower coils. Install the furnace in the order of the prepared materials.
　　 (2) Check the inner cover and seal. Fasten the inner cover, and the inner cover should be tightly sealed. Then perform a seal check. For 120-200 bell-type furnaces, first close the protective gas outlet valve, open the inlet valve, inflate for 80 seconds, and close the inlet valve. If the pressure drop does not exceed 200 Pa after 30 seconds, the seal is deemed qualified, otherwise it is deemed unqualified and processed.
　　 (3) Cold blow. If the seal is qualified, open the protective gas inlet and outlet valve, and use the protective gas to drive away the air in the inner cover. The cold blowing time is generally 3 hours. The cold blowing time is not enough, and the air in the inner cover is not exhausted. In some workshops, the cold blowing is finished after passing the gas inspection to ensure safety.
　　 (4) Snap the outer cover, ignite, heat, and blow. After the cold blowing is finished, buckle the outer cover, and use the ignition rod to light the burners one by one in a clockwise direction to start the heating and heat preservation process. During the heating process, the protective gas inlet and outlet valves are always open, and the protective gas is used to purge to make the heating temperature uniform. The hot blowing continues until the end of the heat preservation. After purging, close the protective gas outlet valve.
　　 (5) Cool down once. After removing the outer cover, buckle the cooling cover, the steel coil is cooled to about 150℃ in the inner cover, lift off the cooling cover, close the air inlet valve, open the air outlet valve, let go for half an hour, lift the inner cover, and the strip steel is out of the furnace.
　　 (6) Secondary cooling. The strip steel out of the furnace is hoisted on the secondary cooling table or kept in the parking area to continue cooling to 40-50°C.
　　Before each process is carried out, it is necessary to check whether the corresponding equipment is in good condition and whether the condition meets the requirements. If the outer cover is fastened, first check whether the burners are all closed and the cooling water on the furnace base is unblocked, etc., before starting the stove circulating fan and combustion-supporting fan, then turn on the gas main switch and open the relief valve, and wait until the discharge is over. ignition.