The invention relates to a cold-rolling hot-dipping steel plate used for a liquid-
crystal module backboard and a production method of the steel plate, and solves technical problems of
cracking and deformation of hot-dipping
steel plates produced from low carbon aluminum killed steel when the hot-dipping
steel plates are used in
stamping forming processes of liquid-
crystal module backboards. The production method includes sequential steps of
smelting according to components, desulfurizing molten iron, performing combined top-bottom blowing in a converter, blowing bottom
argon to a steel
ladle or refining in an LF furnace,
casting low-
carbon steel casting powder while blowing Ar for protection, heating slabs by a
heating furnace, descaling, performing rough rolling, performing precision rolling, coiling to obtain
hot rolled steel coils, uncoiling again, washing with an acid, performing cold rolling, annealing by a horizontal
continuous annealing furnace, performing hot dipping, flattening, withdrawing and straightening and coiling to obtain a finished product. The finish rolling temperature of the precision rolling is 860-900 DEG C. The coiling temperature is 580-650 DEG C. The cold-rolling
reduction ratio is 78-85%. The temperature of cold-rolled
strip steel in hard state in the soaking section of the horizontal
continuous annealing furnace ranges from 730 DEG C to 770 DEG C. The
heating time of the
strip steel in the horizontal
continuous annealing furnace is 80-100 s. The flatness rate after the hot dipping step is 0.6%-1.2% and the withdrawing and straightening rate is 0.3-0.8%. The steel plate is mainly used for the liquid-
crystal module backboard of liquid-crystal and flat-panel displays.