| 摘要 |
PURPOSE: An oxide film removing agent and an oxide film removing method are provided to prevent damage to a continuous metal coating or plating device by using Zn, Al, and Ca as anticorrosive agents. CONSTITUTION: An oxide film removing agent removes an oxide film formed on a metal surface by being diluted in an undiluted solution or solvent at pH 1.5-5.5. The oxide film removing agent contains 0.2-20 w/v% of a hydrazine compound or a hypophosphoric acid-based compound which does not decomposed at pH 1.5-5.5 and is measured by redox titration of KMnO4(potassium permanganate). The oxide film removing agent also contains 0.05-1.0 w/v% of a metal ion in order to delay or restrict corrosion in a steel sheet and prevent damage to a galvanized steel sheet. [Reference numerals] (AA) State before removal of oxide film; (BB) Film processed state after removal of oxide film; (CC) Film processed state after removal of oxide film, SEM; (DD) Embodiment 2(pH2); (EE) CR steel plate; (FF) GA steel plate |
