Effect of creep characteristics on pipeline durability

Purpose: The paper presents an assessment of durability of a steam pipeline operating above the threshold temperature. The durability calculations take into account the creep characteristics of the material. Design/methodology/approach: The results of calculations of the degree of wear caused by the creep of a pipeline, made using numerical methods, are presented. The calculation model takes into consideration the basic geometric and material properties of the pipeline, its operating parameters, and the displacement of valve and turbine chambers which force an initial displacement of the pipeline in the cold state. Findings: As a result of the calculations made, the effect of redistribution and relaxation of stresses induced by the initial guy wire tension has been found. This leads to a rapid loss of stresses, the consequence of which is enhanced durability of the investigated object. Research limitations/implications: Due to the lack of data regarding objects operated for a long time, the calculations of their durability made under this study provide preliminary information on the expected further operational life of a specific structural element. The comprehensive evaluation of the life of an object should be supplemented by research on the material to enable determining the actual degree of material wear in the areas of the analyzed element subject to the highest effort. Practical implications: To ensure operational safety of pipelines operated for a long time, a method is presented to evaluate their durability, which takes into account the effect of additional loads on the effort of the pipeline. Originality/value: In the calculations of wear caused by creep, carried out in line with the EN-13480 standard, the criterion is the stress in the wall of a component under internal pressure. The paper presents the results of stress calculations while taking account of additional operational load, which has a significant influence on the degree of material wear.