Hot dipped galvanized steel sheet with excellent deep drawing properties and ultra-low temperature adhesive brittleness, and preparation method thereof

Abstract

Provided is a hot dipped galvanized steel sheet with excellent deep drawing properties and ultra-low temperature adhesive brittleness, wherein the average diameter of crystal particles of a hot-dip galvanizing layer is 150-400 μm, and the degree of the preferred orientation with respect to the (0001) face of the hot-dip galvanizing layer is 3,000-20,000 cps (counter per second), and a preparation method thereof.

1 . A hot-dipped galvanized steel sheet with improved deep drawing properties and low-temperature adhesive brittleness, the hot-dipped galvanized steel sheet comprising a zinc plating layer, wherein grains of the zinc plating layer have an average particle diameter of 150 μm to 400 μm, and intensity of preferred orientation of (0001) planes of the zinc plating layer is from 3000 cps (count per second) to 20000 cps. 
     
     
         2 . The hot-dipped galvanized steel sheet of  claim 1 , wherein the grains of the zinc plating layer have a diameter of 30 μm or greater and a diameter deviation equal to or less than 40% of the average particle diameter thereof. 
     
     
         3 . The hot-dipped galvanized steel sheet of  claim 1 , wherein the zinc plating layer comprises 30% or more, by volume fraction, of crystallographic twins. 
     
     
         4 . A method of manufacturing a hot-dipped galvanized steel sheet, the method comprising:
 applying molten zinc to a steel sheet;   adjusting the amount of the molten zinc applied to the steel sheet;   spraying an aqueous solution on the steel sheet;   cooling the steel sheet; and   performing a skin pass milling process on the steel sheet,   wherein the spraying of the aqueous solution comprises spraying electrically charged demi-water (demineralized water) on the steel sheet.   
     
     
         5 . The method of  claim 4 , wherein the spraying of the electrically charged demi-water is performed using a nozzle at a demi-water injection pressure of 0.3 kgf/cm 2  to 5.0 kgf/cm 2  and an air injection pressure of 0.5 kgf/cm 2  to 7.0 kgf/cm 2 . 
     
     
         6 . The method of  claim 5 , wherein the spraying of the electrically charged demi-water is performed at a demi-water pressure/air pressure ratio of 1/10 to 8/10. 
     
     
         7 . The method of  claim 4 , wherein the skin pass milling process is performed at an elongation of 5% or less.