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What new processes, new technologies and new equipment are used in the packaging steel strip hot strip mill?
by：Hongmei
2021-03-15
What new processes, new technologies and new equipment are used in the packaging steel strip hot strip mill?
Answer: The main new processes, new technologies and new equipment adopted by Baosteel's 2050mm hot strip mill are as follows:
(1) The continuous casting billet hot delivery and hot charging process is adopted. In order to realize the hot delivery and hot charging process, the main technologies used are: the continuous casting incoming roller table is equipped with a heat preservation cover, the slab warehouse is equipped with a hot billet heat preservation pit, a clamp-type crane spreader is used, and a temperature measurement is set on the front roller of the heating furnace. The heating furnace is driven in sections by a walking beam, and a large turndown ratio burner control system is adopted. The designed hot charging target value is 60% of the continuous casting billet. The average hot charging temperature is 500-550℃, which can be further increased to 650-700℃, which saves energy consumption by 25% and 35% compared with the cold charging furnace.
(2) Low-temperature furnace (1150℃) rolling process is adopted. The main measures taken are to appropriately increase the intermediate billet thickness into the finishing mill and adapt the cutting head flying shear capacity.
(3) Use a low fuel consumption heating furnace. There is a 'heat exchange section' at the furnace end of the slab for heat exchange between the exhaust gas and the slab. The air preheating temperature can be increased to 550°C, and the exhaust gas outlet temperature can be reduced to 343°C. The furnace wall and roof are thickened, the furnace door adopts the best seal, and the furnace cooling water pipe uses double-layer heat insulation linings to reduce heat loss. After taking these measures, the unit consumption of cold billet is reduced to 1292mj/t. The walking beam and fixed beam of the reheating furnace are arranged in sections and staggered, which greatly reduces the 'watermark' of the blank.
(4) Width automatic control (RAWC). Width gauges are set after R1, R2 and R4, and the E2 and E3 vertical rollers are used for automatic width control to overcome the 'watermark' and other factors caused by the change in the width of the strip.
(5) 17 sets of heat preservation covers with a total length of 75m are installed on the intermediate roller table after the roughing mill to reduce the temperature drop of the intermediate strip and reduce the temperature difference between the head and the tail of the strip by about 30°C or more.
(6) The cutting head flying shear adopts an optimized cutting system, which can increase the metal yield by about 0.4%.
(7) In order to ensure rolling accuracy and control flatness, 7 hydraulic AGC systems are used on finishing mills F1-F7, and CVC systems and roll bending systems are used on F1-F3 to control strip crown ( The roll bending system is still used on F4-F7), and a flatness detection device is installed after F7.
Answer: The main new processes, new technologies and new equipment adopted by Baosteel's 2050mm hot strip mill are as follows:
(1) The continuous casting billet hot delivery and hot charging process is adopted. In order to realize the hot delivery and hot charging process, the main technologies used are: the continuous casting incoming roller table is equipped with a heat preservation cover, the slab warehouse is equipped with a hot billet heat preservation pit, a clamp-type crane spreader is used, and a temperature measurement is set on the front roller of the heating furnace. The heating furnace is driven in sections by a walking beam, and a large turndown ratio burner control system is adopted. The designed hot charging target value is 60% of the continuous casting billet. The average hot charging temperature is 500-550℃, which can be further increased to 650-700℃, which saves energy consumption by 25% and 35% compared with the cold charging furnace.
(2) Low-temperature furnace (1150℃) rolling process is adopted. The main measures taken are to appropriately increase the intermediate billet thickness into the finishing mill and adapt the cutting head flying shear capacity.
(3) Use a low fuel consumption heating furnace. There is a 'heat exchange section' at the furnace end of the slab for heat exchange between the exhaust gas and the slab. The air preheating temperature can be increased to 550°C, and the exhaust gas outlet temperature can be reduced to 343°C. The furnace wall and roof are thickened, the furnace door adopts the best seal, and the furnace cooling water pipe uses double-layer heat insulation linings to reduce heat loss. After taking these measures, the unit consumption of cold billet is reduced to 1292mj/t. The walking beam and fixed beam of the reheating furnace are arranged in sections and staggered, which greatly reduces the 'watermark' of the blank.
(4) Width automatic control (RAWC). Width gauges are set after R1, R2 and R4, and the E2 and E3 vertical rollers are used for automatic width control to overcome the 'watermark' and other factors caused by the change in the width of the strip.
(5) 17 sets of heat preservation covers with a total length of 75m are installed on the intermediate roller table after the roughing mill to reduce the temperature drop of the intermediate strip and reduce the temperature difference between the head and the tail of the strip by about 30°C or more.
(6) The cutting head flying shear adopts an optimized cutting system, which can increase the metal yield by about 0.4%.
(7) In order to ensure rolling accuracy and control flatness, 7 hydraulic AGC systems are used on finishing mills F1-F7, and CVC systems and roll bending systems are used on F1-F3 to control strip crown ( The roll bending system is still used on F4-F7), and a flatness detection device is installed after F7.
