Development of Black Coloring Surface Treatment for Bolts Used in Motorcycles

Abstract

In black bolts for motorcycles, both fastening function and appearance quality are required. However, today there is no method that satisfied those requirements because of regulation for environmentally hazardous material. In this study, a new blackening method that satisfies all requirements including appearance has been developed by taking advantages of the color of chemical conversion film using trivalent chromium and the dip-coating that is considering to the weakness of each treatment by the advantages of each.