Quality Of Restored Steel Gas Pipes For Re-Application In Construction

Abstract

The structure and mechanical properties of eight steel gas pipeline single-seam and double-seam pipes that were in operation were studied. It is shown that the degree of corrosion damage to pipe surfaces depends on the chemical composition of the steels. In the studied steels, a significant variation in the hydrogen content between neighboring volumes and the studied pipes was revealed. According to electron-fractographic analysis , there is no significant difference in the degree of embrittlement of the base metal, the weld and the zone of thermal influence. A noticeable effect of hydrogen absorption of steels on the coefficient of anisotropy of the impact toughness has been established, which causes a decrease in the impact toughness on transverse samples to a greater extent than on longitudinal ones. According to the results of mechanical tests for tensile and impact bending, it was found that the restored welded pipes are suitable for use in structures from the first to the fourth groups for the construction, repair and reconstruction of industrial and civil facilities. Naturally, this implies the need for their restoration repair.