Abstract
A lot of pressure boundary bolted flange joints have been used in connecting a lot of piping, equipment, and facilities in some industries such as the refineries, the chemical plants, the nuclear plants and so on. Under utilization of many bolted flange joints, a lot of times and powers are needed when torque methods are applied for bolt loosening. This bolt loosening work by torque methods is expected not only to improve the efficiency of work, but also to pursue a safer work. In this paper, the effect of washers on the loosening bolts is examined. As the result of the investigation, it was recognized that the use of through-hardened steel washers will improve a loosening work by providing a smooth and low friction bearing surfaces for the nuts. The results of investigation using several type of washers in the laboratory and in the actual flange are reported.
