Structure Formation and Nonmetallic Inclusions in Welded Joints when Welding Steel X65 by STT+API Technology

摘要

In work the analysis of influence of structurization and nonmetallic inclusions on regularity of change of growth rate of a fatigue crack in different zones of a welded seam of steel X65 is carried out. Welded seams of the pipelines received by a combined method of welding of STT+API were investigated. Growth rate of a fatigue crack low in a root of the seam received when welding in the way STT. On border of the fatigue crack passing in the filling layers of a welded seam the inclusions which are settling down chains on borders of grains are found, being concentrators of tension.