PRE-SEALED STEEL SHEET WITH IMPROVED ANTI-CORROSION AND WELDABILITY AND PREPARING METHOD THEREOF

摘要

PURPOSE: A pre-sealed steel sheet having improved corrosion resistance and weldability is provided to be environment-friendly because the steel sheet does not contain harmful heavy metals such as chrome, and to exhibit excellent chemical resistance and processability. CONSTITUTION: A weldable resin solution for use in the production of a pre-sealed steel sheet comprises 10.0 to 25.0% by weight of an epoxy resin having a number average molecular weight of 150 to 500, 5.0 to 10.0% by weight of a melamine as hardener, 1.0 to 15.0% by weight of a hexamethylene blocked diisocyanate urethane resin, 40 to 60% by weight of at least one metallic powder selected from the group consisting of Ni, Al, Zn, Fe2P, FeP, Ti and Sn powders, 5.0 to 15.0% by weight of calcium ion-exchanged amorphous silicon dioxide, and the balance of a solvent, based on the total weight of the resin solution. A pre-sealed steel sheet having improved corrosion resistance and weldability includes (a) a metallic substrate, (b) a chrome-free pretreatment coating layer formed by coating at least one surface of the metallic substrate with a chrome-free pretreatment solution, and (c) a pre-sealed resin coating layer formed by coating at least one surface of the chrome-free pretreatment coating layer with a weldable resin solution.