METHOD OF RESTORATION OF INITIAL MECHANICAL PROPERTIES OF METAL OF PIPES UNDER STUDY Russian patent published in 2004 - IPC

FIELD: metallurgy. SUBSTANCE: proposed method includes comparison of results of restoration of initial mechanical properties of metal with mechanical properties of pipes under study for estimation of their further serviceability. Pipes are cut from main pipe line which was in operation and specimens are made from these pipes. Specimens are heated in shielding medium for performing hot deformation by temperature deformation mode of last stage of rolling and cooling at production of sheet steel; then, specimens are subjected to cold plastic tensile deformation by magnitude: ε = δ/2ρ_av+0,012, where ε is magnitude of cold plastic deformation; δ is thickness of pipe wall; ρ_av is average radius of pipe. Then low-temperature tempering is performed and specimens are subjected to mechanical tests and residual life of metal is judged from results of these tests. EFFECT: enhanced efficiency. 2 tbl, 1 ex l