"GB/T 18570.5-2005 Test for assessment of surface cleanliness of steel surface preparation before coating Coating, Part 5: Determination of chlorides on the surface of steel before coating (ion detection tube method) " provides a field test method for the determination of chlorides content on the surface of steel using ion detection tubes. This method is suitable for cleaning steel surfaces before and after cleaning and coating surfaces during painting. The surface chlorides concentration is quickly detected by a special detection tube to provide a basis for the evaluation of surface cleanliness before coating Coating. Standard equivalent to ISO 8502-5:1998, by the Chinese shipbuilding industry group company, the national Coating and pigment standardization technical committee before painting metal surface preparation and painting process sub-technical committee implementation, September 14, 2005 issued, April 1, 2006 implementation.