Electrolytic cleaning study of cold rolled steel using scanning Kelvin probe

Abstract

Oils and iron fines deposit on carbon steel during cold rolling and are removed by an electrolytic cleaning line (ECL). Sometimes localized contamination is observed on the ECL samples. No reliable tests are available for on-line measurement and the off-line tests demand samples with a large surface area. SKP addresses this issue effectively. SKP shows ∼390 mV potential difference between the clean and the uncleaned surface, with the cleaned surface potential being more positive. This indicates that the oil on the steel acts as a Lewis base, whereas the steel surface acts as a Lewis acid. Hence, the potential of the sample increases after cleaning. FTIR confirmed the absence of oil peaks on the cleaned samples. Deposition of an optimum thickness of the silicate layer is another important aspect of the ECL. It was measured by AES which displayed 2.3 nm of the silicate layer deposited on the cleaned steel surface.