Trunk pipelines residual life assessment relatively to metal strain aging
Background Residual life of pipeline is determined by three factors: mechanical properties of the metal, the level of defectiveness and the state of insulation. Residual life assessment of metal pipes accounting the effects of aging is the most complicated process. The problem is that initial mechanical properties of pipes are often unknown. In order to solve this problem it is recommended to use the known theories: the dynamics of change in the coercive force of the metal is closely related to the dynamics of changes in the mechanical properties, tempering of metal pipes in a certain mode restores coercive force to the initial value. Aims and Objectives The aim is to develop a methodology for assessing the residual life of metal pipes on the basis of measurements of the coercive force. Methods Method is based on the results of experimental studies which proved the statements below: the relationship of coercive force and the accumulated plastic deformation of the metal, the ability to recover the coercive force by heat treatment. Results The technique enables more accurate assessment of the residual life of metal pipelines. The technique is based on the coercive force change caused by deformation or tempering of the samples.