CORROSION RESISTANCE EVALUATION METHOD OF ELECTROMAGNETIC STEEL SHEET

• Main Authors: FUJII HIROYASU, KIHIRA HIROSHI, MIMURA HIROYUKI, TAKEDA KAZUTOSHI, YAMAZAKI SHUICHI
• Format: Patent
• Language: English; Japanese
• Published: 11.07.2016
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To provide a corrosion resistance evaluation method of an electromagnetic steel sheet capable of quantitatively and reproducibly estimating a corrosion resistance, particularly, a rust resistance of the electromagnetic steel sheet in an environment that simulates the protection environment, the transport environment, and the use environment of the electromagnetic steel sheet.SOLUTION: Constant magnitude droplets of plural salt solutions different in concentration are locally adhered and dried on the surface of an electromagnetic steel sheet coated with an insulation film. Next, the electromagnetic steel sheet is held to a constant temperature and humidity state for a specified period, and after that, a rusting state of the dried marks of individual droplets in the surface of the electromagnetic steel sheet is observed, and either of the concentration of the salt solution where no rust is generated or the material causing the generation of the rust or both of which are evaluated, or the electromagnetic steel sheet is held for a specified period alternately in a dry state and a humidity state. Then, the rust generation state of the dried marks of the individual droplets on the surface of the electromagnetic steel sheet is observed, and one or more of any of the concentration of the salt solution where no rust is generated, the material causing the generation of the rust, and a dew point of the environment where no rust is generated are evaluated.SELECTED DRAWING: Figure 2 【課題】電磁鋼板の保管環境、輸送環境、使用環境を模擬した環境にて、電磁鋼板の耐食性、特に、耐錆性を定量的にかつ再現性良く評価することができる電磁鋼板の耐食性評価方法を提供する。【解決手段】絶縁被膜が施された電磁鋼板の表面に、濃度の異なる複数の塩水溶液の一定の大きさの液滴を局所的に付着させて乾燥する。次いで、上記電磁鋼板を、恒温恒湿状態に所定時間保持し、その後、上記電磁鋼板の表面における個々の液滴の乾燥痕の発錆状態を観察し、錆が発生しない塩水溶液の濃度、及び、錆発生の原因となる物質のいずれか一つ又は二つを評価するか、又は、上記電磁鋼板を、乾燥状態と湿潤状態に、交互に、所定時間保持し、その後、上記電磁鋼板の表面における個々の液滴の乾燥痕の発錆状態を観察し、錆が発生しない塩水溶液の濃度、錆発生の原因となる物質、及び、錆が発生しない環境の露点のいずれか一つ又は二つ以上を評価する。【選択図】図２