Process method for improving deep drawability of hot dip galvanized IF steel

The invention provides a process method for improving the deep drawability of hot dip galvanized IF steel. The process method comprises the following steps: carrying out acid pickling and cold rolling treatment on a hot-rolled IF steel substrate; carrying out annealing treatment on the hot-rolled IF steel substrate obtained after cold rolling forming, the annealing temperature being 830 DEG C, and the annealing heat preservation time being 30-60 s; cooling the annealed hot-rolled IF steel substrate, wherein the cooling treatment comprises a rapid cooling stage and a slow cooling stage, the cooling speed of the rapid cooling stage is 10-15 DEG C/s, and the cooling speed of the slow cooling stage is 3-5 DEG C/s; and carrying out hot dip galvanizing on the cooled hot-rolled IF steel substrate. According to the method, the annealing heat preservation time is properly prolonged, on one hand, the recrystallization process is improved, and uniform and fine recrystallization grain structures are formed; and on the ot