The results are given concerning the field tests of the longitudinal welded pipes with the diameter of 219 mm made of 05ХГБ steel (9 mm wall thickness), and seamless pipes made of Ст20 steel (12 mm wall thickness). Three factors are established that complicate such studies: presence of thick asphalt-resin-paraffin deposits, the occurrence of local hydrodynamic phenomena in the weld zones of flanges and nozzles, instability of the corrosive activity of the pumped medium. The above specifics mean the need for individual approach to the assessment of the obtained results. Based on the obtained data, the conclusion was made that the manual electric arc welding in the field conditions does not lead to the change in the original structure (deterioration of corrosion resistance) of the pipe metal.
Steel grade 05ХГБ successfully passed the tests on the bypass stand and was approved for industrial use as part of the field pipelines of hydrogen sulfide containing oil and gas fields. Electric-welded pipes made of this material have the fine-grained uniform structure and are more resistant initially to the effect of the pumped medium aggressive components. According to the results of the calculations the pipes made of 05ХГБ steel are not inferior to the analogs of Ст20 steel on corrosion resistance, and even exceed them, if the influence of hydrodynamic phenomena and mechanical stresses in the zones of flanges and nozzles welded joints are considered.
Use of electric-welded oil and gas pipes of 05ХГБ steel grade will make it possible to abandon the thick-walled seamless pipes, thanks to that the metal intensity of pipeline transportation facilities will be decreased, and the cost of capital construction, repair and reconstruction of the pipelines will be reduced as well.