Method for improving dent-resistance of a steel plate

Abstract

The present invention relates to a method for enhancing a dent-resistant property of an outer panel of a vehicle. Pre-straining is performed to a steel plate by applying a certain reduction rate during a skin pass mill process performed for enhancing a density of a steel plate and adjusting a shape of the same, so that it becomes possible to enhance yield strength of a steel plate and to obtain an excellent forming property. The present invention is basically directed to fabricating an outer panel material such as a roof, a door, a hood, etc. of an excellent vehicle material having an excellent forming property and dent-resistant property. Therefore, it is possible to decrease a thickness of a vehicle material based on an enhanced strength of an outer panel of a vehicle. The present invention may contribute to a government environment regulation counter measurement and a combustion ratio of engine.

1 . A method for enhancing a dent-resistant property of a steel plate comprising: 
 pre-straining a steel plate by tensile forces acting along one axis;    performing a press process with respect to the steel plate; and    enhancing yield strength of the steel plate based on an increase in the degree of work-hardening.    
   
   
       2 . A method according to  claim 1 , wherein pre-straining the steel plate comprises performing a skin pass mill process on the steel plate, and the skin pass process comprises a reduction rate between about 1.8% to about 2.0% when a cold-rolled steel plate is fabricated.