The pipe material and improvement state analysis of technological processes for laying main gas pipelines

The change in the structural state of gas pipes’ weld material at different seam cross-sections have been considered. classification external and internal defects joint caused by influence types factors, most significant which are transition zone to pipe base metal. analysis atmospheric effects on pipeline welds materials initiating adsorption electrochemical processes metal microstructure that cause corrosion outer surface is given. Taking into account non-stationary mode pipes loading due fluctuations pressure, corrosion-fatigue damage also added these defects, fatigue cracks development material, leading a violation system tightness even destruction. structure mobile device proposed for performing complex technological operations assembling large-diameter ground ensuring installation accuracy maintenance processing welded edges, automatic welding along perimeter, cleaning, grinding hardening surface, applying protective coating against influences. facilitates work staff, increases reliability bearing capacity transmission installed difficult terrain.