The invention discloses a production technology for preventing 'core collapse' defect of ultrathin steel coil. The production technology comprises: uncoiling a
raw material steel coil by an uncoiling
machine, clamping the head portion of the band steel by a clamping jaw of a recoiling
machine, and coiling 1.5 circles of the band steel, then rolling the band steel for 5 to 7 times, rolling the band steel of 2.5 to 3.0 mm thick into a thin band steel whose thickness is less than 0.3 mm, and then coiling the finished steel coil by the recoiling
machine, putting the finished steel coil into a warehouse after coil discharging, weighing, and bundling. A
high tension start technology is used for coiling the finished coils, the core portion start tension is increased to 1.6 to 2 times of the set coiling
tension stress, then the core portion start tension is gradually reduced and returned to the set
tension stress of 70 N / mm2 when the outer
diameter of the steel coil is 800 mm; the clamping jaw is reversed after the coiling block is shrank for 2 degrees during the coil discharging. The production technology for preventing 'core collapse' defect of ultrathin steel coil employing a
hard core tension cold rolling method without increasing the number of coiling circles is able to saved the cost of manufacturing sleeves and the cost of transportation, thereby effectively removing the 'core collapse' defect of ultrathin steel coil, and increasing the production
rhythm and efficiency.