Being one of the largest transmitters of natural gas, Ukraine has pipeline systems technologically connected with similar pipelines in Russia, Belarus, Moldova, Romania, Hungary, Slovakia and Poland, and through them with gas pipelines throughout European continent. The urgency of studying of the influence of pH on the characteristics of corrosion-mechanical processes exists since Western Ukraine land, where the significant portion of strategically important pipelines is located, is characterized by acidic soils with chloride and chloride-sulfate electrolytes. The risk is greatest in acidic environments, because of the special sensitivity of long-term exploited pipeline steels to hydrogen embrittlement. Therefore the purpose of the work is to research long-acting exploitation environments and work terms on deformation behavior of pipeline steel in acid soils. As the object of our study we have chosen main gas pipelines of large diameter made from steel 17HS that have been in service for 41 years. To study the kinetics of low-temperature creep corrosion we have selected three levels of nominal stress according to the size limits of the yield stress of the pipeline that meet the staff, increased staff and part-time modes of the pipeline and are respectively 330, 420 and 510 MPa. On the first stage of the study long-term exploited pipe steels were testing in acidified chloride electrolytes. With the increase in the nominal value of the stress intensity deformation process increases. At the top, near the border of strength exercise, we watched the curve creep slopes. And the characteristic is that they are sharply degraded material and begin to appear at lower levels of stress (already visible at 420 MPa).With further decreasing of pH to 4 (ME2) we fixed significant deformation fluctuations. Clearly there are cycles of acceleration-deceleration strain responsible for crack growth cycles. They are the most intense in the first stage of exposure, further the speed of deformation decreases. Deformation behavior of long-term exploited steels at ME3pH 3 is more predictable. Thus, our conclusions are as follows. The authors have studied the influence of continuous service and pH characteristics of resistance to deformation of pipe steel 17HS. We have identified the use rate of the angle of inclination of final section deformation curve as the non-stationary characteristics of corrosion-mechanical processes and have shown that the most dangerous to long-term exploited steels are ME1 and ME3. Further to extend assortment of pipe steels we have investigated for integrated assessment of potential operational risks caused by corrosion and mechanical processes.