Corrosion Testing of a Steel Oxide Covered Surface

Standard corrosion test methodology starts with  the removal of surface features such as millscale. Millscale is an oxide formed on the steel surface during hot rolling. The millscale is rarely removed before field installation unless the surface has been specifically prepared, such as for coating applications. Therefore, many surfaces experiencing corrosion will, at least initially, be covered by millscale. A testing methodology has been developed to test the corrosive response of an steel oxide covered surface.  Results from an X70 line pipe grade steel covered with millscale in deareated 3% NaCl solution at a ph 6.5, demonstrate testing methodology.