PROCEDURE FOR EVALUATION OF REMAINING LIFE OF GAS MAIN METAL Russian patent published in 2010 - IPC F17D5/00 

FIELD: machine building.

SUBSTANCE: there are cut not less, than 3 plates of gas main metal, for example from pipes of emergency stock. One plate is used as a reference sample, while others are installed inside the gas main at places accessible for periodic inspection. During preventive maintenance one of the plates is taken out. A layer of 0.1-0.12 from thickness of the plate is cut off the surface facing inside the gas pipeline. There is carried out analysis of distribution of hydrogen atoms concentration along thickness in the reference and cut off element of the extracted plate and coefficient of hydrogen atom diffusion is determined. During the successive repair the investigated plate is returned inside the gas pipeline, and another plate is taken out and investigated by the same procedure. Further there is estimated dependence of change of hydrogen atom concentration along thickness of the plate of the gas pipeline. On base of obtained results remaining life of material of the pipeline is evaluated.

EFFECT: increased reliability of assessment of remaining life of metal of pipeline during operation.

3 dwg