Evaluation of rust friction surface of bolted joint by a colorimeter

The purpose of this study is to establish a management method and digitized color index of appropriate rust friction surface to ensure the slip coefficient of high strength bolted friction joints more stable and higher. The rust generation were measured using a colorimeter under various conditions (removal method of mill-scale, temperature, humidity, strength of the steel, surface treatment, interval time of spraying water, type of water, chemical treatment and so on). From these measurements, we suggested that the chroma of digitized color is appropriate for an index for evaluating the rust friction surface. Therefore, from the results of slip test of high strength bolted friction joint, we obtained a conclusion that the slip coefficients can be evaluated by the chroma of rust friction surface, regardless of the rust generating process.