Assessing changes in stress-corrosion damageability on the basis of repeated in-tube nondestructive testing

On the measures that are necessary for providing the safe operation of pipeline transport with nondestructive testing facilities

“…(3) The manufacturing of pipes from a steel hardened by controlled rolling; (4) The presence of nonmetallic inclusions in steel; (5) The presence of internal residual stresses in pipes and the application of external tensile stresses; (6) The action of cyclic and seasonal temperature and strain loads; (7) Retesting of pipelines; SHCHERBININ et al (8) Disadvantages in the cathodic protection of pipelines; and (9) Metal fatigue. For gas and oil pipelines, we should especially emphasize the factor of hydrogen embrittlement.…”

“…(4) A poor quality steel leading to the sharp thinning of the wall in the lower part of a pipe under the action of an aggressive medium (the rates of uniform overall corrosion and pit development vary from 0.15 to 1.5 mm/yr); and (5) High internal stresses, especially, in the zones of high tensile stresses. The main causes of the appearance of such flaws are the nonoptimal and nonuniform chemical com positions of pipe steels, poor quality rolling, the nonoptimal and outdated technology of the manufactur ing of pipes, the scatter of process parameters, the violation of technical discipline, and the absence of control of the results of intermediate technological operations.…”