| Popis: |
Mechanical and physical properties of bainitic steel 15Cr2MnMoV used as a material of oil pump rods were studied in three states: as received, after operation in hydrogen sulfide-containing environment, and after hydrogen charging in H2S-containing media for 1 week. In addition, the austenitic corrosion-resistant steel 12Cr18Ni10Ti has been studied in two states: as received and after operation for 6 years. No degradation of the standard mechanical properties of the investigated steels after operation was revealed, although a decrease in the fatigue properties of the austenitic steel 12Cr18Ni10Ti was observed. Mechanical properties were most affected by hydrogen charging of bainitic steel, after which a decrease in ductility, fracture energy, and fatigue life is observed. Four stages of fracture development of the investigated steels under tension are distinguished. It is shown that acoustic emission is the most sensitive method for assessing the degree of structural degradation after operation or hydrogen charging. It is established that the magnetic methods of nondestructive testing show the greatest sensitivity at the elastic stage and at the stage of deformation localization before fracture. |
